Certainly wasn’t expecting a mention… and I was still laughing at Edwin’s antics when it came up! Anyway, re: the KB incident, if your previous videos didn’t convince people that your design will not fail under (anything approaching) normal use, I’m not sure anything will. It sucks that you need to defend your good name.
and KB did a video it as well and its seems a lot of people in the comments haven't seen it and KB did it with a barrett the gold standard of 50 cals and it blew up just the same.
One of the most telling things about this whole debacle is that I've only heard criticism of the design come from non-engineers. As an aerospace engineer, we don't design for margins anywhere near what you do, so when I hear that the action failed at 400% of the cartridge spec it's amazing to me that it got that far. Nobody expects you to be able to take a Honda civic and flow 10 kg/s of nitrous through the engine without catastrophic failure. Guns for so many people in the community are just strange magical blackboxes bullets come out of and God forbid if you remind them they are machines like any other.
Not an engineer, but when reviewing pressure tanks that exploded, the one part always intact was the threads. Just seemed like common sense that threads were always a stronger connection in pressure situations than lugs. Wish the so-called TH-cam-experts would have discussed that and shut down some of the hyperventilating about a threaded breech.
I fuind it amazing how the stoner ar design was great BECAUSE, a aerospace engineer designed it... imagine how great an airplane would have been if designed by a gunsmith?
If all guns were designed for the absolute max compressed load of the fastest burning powder available for the particular round chambered, you can bet the farm that the same complainers would be boohooing about how heavy and massively overdesigned the weapon is. Why does my 300 winmag have to weigh 20lbs stripped?
On the flip side, thinking about consciously putting your face mere inches from an explosion with tens of thousands of PSI's of pressure to simply expel a small bit of metal in an intended direction isn't something that everyone really wants to think about.
A man almost died. Regardless of any factor, every single thing related to that accident requires in depth analysis. A lot of companies, once they realized they were clear of a lawsuit, wouldn't have given two fucks. The fact that Mark himself cares enough to dedicate this much time to the incident after the fact really says a lot of positive things about the company.
This is where I was going to go with my comment. Mark is going way beyond the call of duty with his continuing analysis. I would suspect he donated the testing guns to KB for his destructive tests. Edwin mentioned he was sending his back to Mark after his concrete testing, I’d bet Mark ate that one as well. If I had a desire for one I would not hesitate to buy and use. I’ve shot 50’s and I don’t see any practicality in it for me.
@Kinzie Conrad Did you not even watch the video? They buried the barrel in 4 feet of concrete and it still didn't break the threads, you're an idiot lol
I'm a bit flabbergasted how people thought a piece of plastic had enough tensile strength to withstand enough force for the back of the gun to blow up rather than the plastic. ON WHAT PLANET IS THAT POSSIBLE? - ok watching the rest of the video now.
@@markserbu Even worse: Shotguns with chokes. D: Honestly, people making these comments likely didn't watch any video on the matter to the end, and have invested exactly 0 seconds into thinking about / reading into materials science.
Exactly what I thought from the very beginning! It had to be something other than the proper powder loaded in that round. Glad Mark is vocal about this and calling out the stupid “dog bark”ing people and their comments.
Most people are dumb...They don't try to understand the physics behind something and they make up what reasons they think work best instead of actually listening to engineers and other S.T.E.M. qualified people that can explain it through math and sketches. As for the younger generation ..we've seen so much dumb shit online we can spot a troll most of the times.
The problem with surplus of unknown storage and transportation history, some could get exposed to excessive heat and/or movement, degrading the inhibitors, greatly increasing burn rate.
I find it “funny” that even though Scott himself said the gun was not to blame people went out of their way to make assumptions and call you/your business out based on nothing but speculation.
@@manbaby9166 New Kentucky Ballistics Mascot be like Scott-borg, a man of steel and heart who has come from the future to stop evil inflatable dinosaurs and eggplants
I think part of it is the design already sketched a lot of people out. Tbh before all this I saw the rn50 and was like fuck no, that things like a fucking factory made pipe gun, I don't trust that not to become a factory made pipe bomb in my hands. When KB happened i was like "it was only a matter of time". Ironically in the long run it took it blowing up to convince me I should get one. After having seen all the testing I'm a lot more confident in it being safe and fun to own.
What is failsafe? You cannot prevent failure, but you can make it fail more safely. For example, if the top of the barrel was intentionally made weaker than the cap, then the rifle would blow-up upwards, instead of blowing-up in your face.
Anyone who's taken a physics course, or a materials course... and passed, knows that the pressure required to rip the threads off even a grade 5 bolt of that size is phenomenal. Mark builds a good gun. I just got my new Serbu 50 cal and shot it the first time last weekend... not a worry in my mind. Keep up the good work, Mark.
Obviously everyone who's talking shit about the gun doesn't know anything about engineering and design. A part (can be just a beam of steel, but here the gun) has to withstand certain forces. It shall be designed in a way it's safe for normal use. For mistakes and stuff the part can usually withstand around 1.5 times the normal force. Beyond that, it's not the designer's fault.
You forgot to multiply the thread load capacity by the 2 fucking 1/4" steel backers behind it that the cap completely sheared off like they didn't exist. People are just ignorant. I don't know where the 200k psi rating Mark threw out came from but it seems a little low to me. To move a cap backwards fast enough AFTER failure to sheer off that much steel, it had to be SIGNIFICANTLY over the failure load, not just slightly. If it was slightly over it would have dented the steel and then deflected up.
All BS aside, the RN50s rep took a beating in the court of public opinion. I could not imagine anything more infuriating than being judged on something,that the firearm was never designed for,by a bunch of people that know just enough to sound like they know what they are talking about. Carry on Mark. Thank you for doing all you can to educate the masses.
@@CAMSLAYER13 The ammo was in question from very early on, it was determined it was the slap rounds mere weeks after incident happened, it was covered by marked himself then not long after that KB destroyed another RN 50 to demonstrate the forces needed to destroy the breach cap as well as the lugs that everyone likes to get philosophical about. Truth is nothing would have survived that,… there was a dude not long ago that loaded a tube mag shotty with questionable ammo… it chain fired the whole mag disintegrating the fire arm and indeed his own arm. Now , do we demonize that model of shot gun because of the incorrect ammo, or,as animals equipped with the powers of deduction, rather than flock mentality, do we identify and remove the greater hazards? Mark is clearly annoyed and rightly so. Half informed critics are as useless as biased ones.
@@riz3nfpv306 He has every right to be upset but, unfortunately it's the way it is, the damage done cannot be reversed. Sucks for him, but the gun has a bad reputation now. KB's video will always have more views than any of these video's, only very few people in contrast will see any of the breakdown videos.
@@kinzieconrad105are you saying it blew up because of the threaded breach cap? Do you think an m4a1 would have done better ? Get educated bud… or be one of the guys we can laugh at
@@Chzydawg I don’t know which are dumb and which are dumber. The ones starting the BS or the ones Taking it as the truth. It actually is saddening, you need to remember producing an item to supply to the public is a difficult enough task. You guys are blessed to have guys like mark in your country to design and supply these products. Also the birth of the RN50 was to supply a need in the market for a budget 50 cal…he listened to that need,why tear him down? If a guy like mark comes under scrutiny from his peers in his community, and is found free of liability, he should be supported. Not continually dragged through the mud Ok fair ,in the name of safety - IF the gun was faulty sure get it out there - but it’s not , why keep up this fallacy or misinformation? Why not go after the guys that supplied the rounds?I don’t get it.
From the test that Kentucky Ballistics did, someone tampered with the SLAP rounds that he bought, and loaded them way too hot. The ammo was to blame, not the rifle.
When you obtain ammo that has never been offered to the public, what is available "fell off a truck somewhere", you are taking a very big risk especially considering the price these rounds bring.
@@aethelon4144 No, it had to be the wrong powder. Even a compacted load in the .50 wouldn't cause that serious of an over pressure, it was most likely pistol powder.
@@ZE0XE0 The burning rate of the powder used is very important, faster powder as used in pistols is less dense than slower powders used in rifles, a case full of fast pistol powder could be responsible. Or something other than gun powder inside the case.
Thanks' so much Mark, this was great info I didn't know. We shoot a lot of SLAP rounds on our channel but were only going off what everyone else said as far as muzzle brakes go when we first started shooting the SLAP rounds. At first, we were shooting them with the brake off, but the dang thing kicked so much Justin made an insert (basically a machined tube with a bunch of holes in it) for our Bushmaster BA50's big old honking brake and it works just fine. Thanks for the common since showing the footage of the rifle blowing up, and one no in cement. It doesn't much clearer than that.
@Going Ballistic Thanks! As pretty much everyone knows, the plastic sabot *can* damage a muzzle brake. In extreme cases, pieces can be blown off and fly backwards at bullet speed. Hell, in the prototype phase of the BFG-50A we had brakes lose some pretty big chunks, and that was just from propellant gas! Excellent idea with the perforated tube insert!
Been following along from the beginning. As a Mechanical Engineer (now retired) specializing in Forensic Failure Analysis for over half of my career, I find it fascinating the process you have gone through to this point! There's an old saying: "The Devil is in the details". 🤔
Same here @David Hughes! I can see how uncomfortable saying some of this is making Mark Serbu!, and learning internet culture where Keyboard Warriors can verbally assault people who they wouldn't fecking *DARE* to mouth off face to face is a lesson that can be hard to learn!. Fair play to Mark for his openness!... As for Failsafe, I.E. PROOF-ing *anything!* a great *Old* saying is it's hard to *FOOL* -proof *ANYTHING* because they just keep making more ingenious *FOOLS!* by the way that's not a dig at *KB* ,I think Scott is cool as feck! Keep your head up and keep doing your thing Mark!
I want to see a knock off version of RN-50 by Hi-Point or some other low-end manufacturer from China or Ghana or Peshawar....then we can look forward to some real carnage.
The only thing that scares me about my RN50 is the thought of carrying it more than 20 feet. And firing more than 10 rounds in one sitting. Fantastic rifle and the most cost efficient method of delivering 50bmg to a target.
@@jacobkudrowich The only difference between men and boys is the price of their toys. If putting 30 bucks of ammo up in smoke bothers you don’t ever own/shoot a machine gun, Gatling gun or shoot rifles chambered in most classic “dangerous game” cartridges. This is why traditionally most metallic and competitive shotgun shooters reload their own ammunition. For me and many other shooters who reload their ammunition it brings another element of enjoyment to shooting sports.
You are 100% correct. I’m a retired engineer and I know that what happens at the muzzle brake can not cause the chamber to fail. The muzzle brake is the weakest part of the weapon, and by the time a projectile reaches the brake the chamber has already reached and passed its maximum pressure.
Also the fact that there was no damage to the barrel, no expansion or peeling, proved that as being wrong. The barrel is strong, but it would be an extreme oddity for a barrel of any kind to be stronger than the chamber. The nature of gun design alone makes that unlikely, and the fact that the barrel is threaded into the receiver which is providing additional support for the chamber. It was clear to me from the first video of the explosion that it was a massive over-charge, and when things exceed the expected worst-case possibility design, it is impossible to predict the outcome.
I own a Mark Serbu designed 50A rifle, I’ve had many conversations with Mark and his staff, smart people, great accuracy and I shoot my own reloads. 3 rounds touching at 300 yards. Hang in there Mark, this to shall pass.
Kentucky’s blowup, from the perspective of a reloader, looks like classic overloaded round. Barrel obstructions USUALLY banana peel the barrel, not blow the back of the bolt/chamber open. Especially seeing him fire the rest of the ammo from that batch he bought, almost every last one gave clear and loud warnings of a hot load. Whether the failure mode of the RN-50 could or should be different is another conversation, but the ammo caused the blowup. I’d bet a not inconsequential amount of money on it.
A little stupid thing that some ill educated gun nuts do is clean and shine their loaded brass in a vibrator , a big no no, you literally remove all coatings off the powder and if it's double base powder you quite literally have made a very destructive instrument, can't say the word TH-cam won't let me , video creators can but commenters cannot.
As seen by his other demo tests of guns, there's not really a design out there that would be much safer than the RN. The Barrett is the gold standard .50 and that thing would've still likely killed him
I could see that as well. In all of the pictures I've seen of obstructed barrels being fired into, there was ALWAYS at least a bulge starting near the obstruction point, and very often splitting. It's the thing every reloading manual has warnings about. An over-charge can cause excessive wear or binding on the action and a massive over-charge will blow out the action. The pressure spikes too high before the bullet gets out of the barrel. The fact that all but one of those SLAP rounds were over-charged to an extent is plenty of evidence that one or two could be explosively so. When you're hammering, or otherwise using tools and force, to open the action, your rounds are too hot. Except on a Mosin. Hammering is expected.
@@Robert-qm7yi This was my thought as well. That pressure wants to go somewhere, and if it's going anywhere but forward, there's a good chance you're going to be on the receiving end of whatever that pressure is dumping it's kinetic buildup into. Be it the end cap and lugs of the gun, or the remains of the receiver folding over backwards into your face. At the end of the day, you're sitting inches away from a contained explosion that's almost _four times_ the rated pressure of the rifle, at an already extreme pressure rating. The only way i see to account for that is to over-engineer the hell out of it and hope it doesn't fail, because at those kinds of pressures, no failure mode is going to be pretty. EDIT: Forgot how fucking insane the pressure actually was, just looked it back up because i wasn't sure. I still can't believe Scott's alive.
Regarding "fail safe". This is like when people ask locksmiths for locks/chain that will stand up to an angle grinder cutoff wheel. **Nothing** stands up to a cutoff wheel. "Okay so we sell this hardened security chain by the foot, right?" "Yeah..." "How do you think we cut it to length?" "... oh."
@@mephInc Surely the criminals won't take the path of least resistance... surely... Of course, depending on how high said criminal is, ya never really know!
The way Mark has handled this-- and this video in particular-- really inspires confidence. I'm an engineer and gun enthusiast and all of Mark's remarks have my engineer brain nodding in violent approval. There's no such thing as fail-proof. Just fail-resistant. For example, I can layout some hydraulic hoses with different sized ends to make it only go together one way, but a trip to the local hose shop for an adapter and just like that it's plumbed wrong. Mark's analysis is spot on, and it shows a dogged determination to vindicate his design-- which I sure as heck would also want to do if it was MY rifle that ignorant people were accusing of being at fault.
The whole "sabot plastic is getting stuck in the muzzle break" thing is easy to disprove. Just remove the muzzle break and try the same thing again. With the same load, the gun should blow up "just fine" without the muzzle break.
Pack the barrel as tight as you possibly can with discarded sabots and fire the weapon. I would fire it from the hip I am so sure nothing would happen. Teh problem was bad ammo. probably leftovers from project eldest son.
US Army small arms repairer here. IIRC, it has been many years, sabot rounds arent supposed to be used with a muzzle brake OR flash hider. (yes even the conical flash hider for the M2) because the sabot separates from the round at the end of the rifling. If a muzzle device is attached it can cause the discarded sabot to ricochet off the device and strike the round, causing a deviation in the point of impact. It doesnt happen often, but often enough for the US military to advise against it. A micro deviation at or near the muzzle, can have a huge impact at 1200 meters and beyond. Small dents and dings in a flash hider have very little impact on the weapons operation. A round striking 50- 100 meters outside the impact zone, can have catastrophic results for both the Military, and any civilians or military personnel outside the impact zone. 5 of the 6 branches I know use both the M2 and the Barrett, USA, USMC, USN, USAF, and USCG. I have no information on if the USSF uses either system. The directive on this did not come from any of the branches individually, rather it was a DoD issued directive. Just my humble opinion based on the information I have been exposed to over 28 years in the US Army. I could be wrong.
m.th-cam.com/video/3c4wtfV5_ao/w-d-xo.html In this video he says it's not the slap engaging with the muzzle. He also hates my idea of chamber vents. I don't see whats wrong with the chamber vent idea.
I know they didn't let our sneaky squirrels use them in the barrets. They didn't like us using them in the ma duce that much either. I could be wrong, but it's my opinion that was mostly because those rounds were getting pretty old and they didn't trust them much because of the age. I'm pretty sure we only had once can issued in our entire company, and we got it on a fluke. After the accident I tend to agree. I'm pretty sure that nobody has loaded new SLAP rounds in a very long time.
Hey Mark 🙋it was clear after Scott's test video, that the ammo was significantly overcharged. If gas prices weren't so godawful high I'd put an order in for an RN50 today. Keep being awesome.
For some reason they decide to go on a witch hunt after Mark even though the ammo used during the accident was, as you said, overcharged. A normal .50 round would never be able to shear the steel threads on the rn50. (In my opinion)
Interesting fact I learned afterwards is that a "undercharged" round can also blow up stuff badly. At first it don't make sense. Once you think about it tho if a round has more powder inside it, less surface area of the grains of powder are exposed to the flash over as it ignites. However if you have less powder it exposes up to like 3× more powder right away as it flashes over and it will cause a higher initial spike of pressure. A casing loaded with more powder has a longer explosion but at a slower rate. If that makes any sense lol. Then a cartridge that has a round pushed down inside it will go off like a stick of dynamite as it will go off nearly at once and have the highest spike I think. Someone who knows this stuff better can weigh in and explain it all better. Neat stuff tho. Unless you're the guy being exploded. Then it kinda cramps your style a bit lol Just go ahead and give yourself a tracheodomy before testing weird loads made by a stranger and you'll be fine lol
@@hughgrection3052 this is common in nitromethene racing, they literally wash the cylinders with fuel, so much so that the engine is constantly teetering on Hydro lock, even at red line. If you want to hear more, let me know
It’s so cool how much responsibility he takes over this even though it wasn’t really his fault. He wants to make sure this never happens again. To anyone.
I just want to say that seeing the way you reacted to this freak accident & the amount of time dedicated to figuring it out has made me want a Serbu more than ever! RN-50 will likely be the first 50 I get. Products fail at some point, it's impossible to realistically prevent. How the designers of those products react to the failures speaks FAR louder than any durability test in my book
Before the gun blew up, I always thought the design of the RN-50 breech screw plug was just supposed to be a cheap way to make a gun. Never considered the safety. Then I researched the sheer strength of threads vs lugs. It’s amazing how much more secure threads are than lugs. So, the RN-50 is probably more safe than the other 50 cal rifles.
Threads are only safer when properly machined and torqued. Threads also don't take very well to wear and repeated cycles as well as lugs do, which is why they're the most common design.
Threads were used on breech loading cannons right up until WW1 and are still used in some modern artillery. Talishar doesn't seem to be the most informed commenter on this. He has a point about thread wear but as I said interrupted threads are used in some modern artillery to this day. The RN-50's design has the ears to ensure the minimum amount of thread length engagement. I don't believe the RN-50 uses a tapered thread so... meh If he really thinks the design is unsafe, I'd love for him to put his money where his mouth is and do the Reliability Analysis. Show me the weibull baby!!
The most succinct, informative, and in my mind definitive review of this KB was done back when it happened on a channel called Backyard Ballistics. Despite the name, the guy is an educated professional firearms examiner tasked with gun crimes & failures. Right off the bat he said that just the threads being sheared showed it was the ammo and not the gun design. He explained several other aspects, like how a failed case will greatly increase bolt thrust, hence his recommendation for gas vents, why low-cycle fatigue is ruled out, and a lot more. Highly recommend anyone interested - you too, Mr. Serbu - check his two vids on the subject.
I'm glad this "rebuttal" has FINALLY come out. Thank you Mark for putting it in perspective and leveling the field of commentary. I laud you for your intestinal fortitude and telling the facts regardless of "popularity".
Common sense is a flower that does not grow in everyone's garden. It's refreshing how confident you are in your engineering and your willingness to tell people they are idiots when they are being idiots. Entirely too many people are overthinking this entire incident and looking to place blame where it doesn't belong. Keep up the great work.
I'm glad that Mark (although jokingly) called out Edwin about his Oxygen Bottle in a Safe antics........ that was super stupid. Sarkissian should know better than that.
@@phalanx3803 yes, and that does help eliminate hostiles. There's a minor problem, the angry binary noises coming from the local techpriest at such a ancient and revered weapon being so mistreated.
2,000 rounds through my BFG50 and I couldn’t be happier with the platform. Mines in .510 DTC so the ammo is all handmade by myself and therefor far from perfect which should expose any weapon short coming quicker than more consistent ammo production processes. Thanks for what you do for our community Mark!
From my engineering armchair: you don’t need to make it stronger you need to make it weaker. You want the RN50 to fail in a way that would send shrapnel down range. Add flutes to the receiver to make it weaker then the bolt cap - that would be failing safe. What you described as fail safe was a design that would never fail. Keep up the good work Ps I don’t believe this was RN50’s design is at fault but every design can be improved.
awful idea. That sounds like a great way to turn an action into a hand grenade because you're purposely giving it weak points to break apart at. The gun as built can handle proof rounds all day so it's plenty safe for the designed operating parameters plus a safety factor. Buy trustworthy ammo or load your own if you know what the hell you're doing.
Exactly. Fail safe means that when it fails, it fails in a safe way. It does not mean that it never fails. IMO, the problem with the RN50 is not the threaded breach plug, but the two support lugs behind the breach cap. In both explosions on KB's videos, the support lugs became lethal fragmentation.
@@mckennaConfig The lugs probably slowed the cap down enough so it didn't just go through his skull. If I remember correctly, it hit the lugs then went up and hit his safety glasses, which also probably spread out some of the impact, and it still broke his eye socket in a "glancing" blow. Being hit by it straight on would more than likely killed him.
Weak threads? Anyone ever look at hydraulic cylinders? Its all held together by fine threads that hold back all that pressure for hundreds of thousands of cycles. 100% wasn't the fault of the threads, definitely an over charged round or and war relic sabotage round with C4 in it that happened to find its way into that batch of ammo. I'd definitely recommend weighing each round of ammo looking for discrepancies when buying old ammo or from anyone really when talking about .50BMG.
Some artillery pieces use an interrupted thread to secure the breach plug. There is absolutely nothing wrong with a threaded plug or cap with adequate sized threads and proper contact. Given that Scott from KY Ballistics did another test and ran seriously overpressure rounds through an RN50 without failure, I'd say the RN50 is just fine. It took making what was effectively a little pipe bomb to break the gun.
@@RustandRedemption The engine in your car does the same thing with a spark plug. An engine at 3000RPM is spinning 50 times a second and in a 4-cycle engine, that means 25 explosions per second per cylinder that your spark plug not only contains, but ignites as well, thus placing itself at ground zero for the combustion event. Absolutely nothing wrong with threaded plugs or caps.
We colloquially use "failsafe" to mean cannot fail, but that's not what "failsafe" actually means. It means that when something fails, it fails in a safe way. Usually in the form of an intentional weak point. I'm not sure how a failsafe could be designed for this problem. As you point out, simple case vents aren't going to do much.
@@muwuny Did you watch the video? Did you listen to the words that the man said? Did you understand what the words the man said meant, or not-even-close? Because ^The Evidence^ here would suggest at least 2 "No"s in answer to my questions, but hey, you keep-on trying to talk to the grown-ups if it makes you feel clever Buddy... 😉👍
@@muwuny you know what the weakest point in a firearm HAS to be? An unobstructed barrel. Any other weak point and explosive pressure will find it. Maybe not on the first round, or the first 500, but eventually that "fail safe" will fail when it doesn't need to and cause issue. Pressure will follow the path of least resistance, so if that less resistance is anywhere other than pushing a projectile down a barrel, then you don't have a firearm.
@@muwuny You're dealing with pressures at 300% of the pressure rating of a .50 bmg cartridge; More than 180,000 PSI. There's no way to make that fail safe, anything releasing that much pressure in any direction other than away from you is going to end badly, usually very. That energy is going somewhere, and if it's gotten to the point where the equipment starts failing, it's usually everywhere. When you're dealing with extreme equipment, safety is usually managed at the individual level, not the equipment level, for the simple reason that, under extreme circumstances, you just can't get something to fail safely. Precautions need to be taken, safety needs to be considered at every step along the way, and both of those need to take priority over anything else. Simple fact of the matter is that Scott got a bad reload. A very, very bad reload. There's no accounting for rounds that operate at near 400% of conventional cartridge pressure, that's like taking a hair dryer and hooking it up to high voltage lines. And when failsafes aren't really an option, the only thing we can do as a community is learn to take precautions, to consider safety more. Because in the end, Scott fucked up. He didn't _know,_ he couldn't have... But there's lessons to be learnt in every accident, and i don't think the lesson to be learnt here is one that we can simply push off to engineering, and wish them best of luck with it. This one's one we can all learn from. And for the record, _no rifle in existence has a 4x operating pressure failsafe, quit the vindictive bullshit._
I'm glad you are talking about this Mark, I've loved your weapons from afar as a poor Canadian. I have nothing but trust in your commercialized designs and wish I could buy them. One day, I'll own your BFG, and your RN50, but again, thank you for talking about how your RN50 works and what went wrong. Especially for giving Scott another one to blow up.
We saw Scott shoot multiple SLAP rounds from the RN-50, and no issues. One super hot round was all it took, he even went back and remotely fired the rest of those bullets with NO ISSUE. Keep up the great work, Mark, that's a helluva weapon you've made.
the people pointing out the "weaknesses" of the screw cap clearly have never seen how artillery or naval guns work... those breach blocks are literally threaded, well partially since they're typically a 90° lock which means there's LESS material thread wise in contact between the block and the barrel.
Yeah in the military we had way worse examples that didnt fail. Now I have never fired a RN50 but I would trust its screw cap, because I trusted things like chicago fittings for high pressure liquids and gasses. You hit the nail on the head with this one.
@@Uryendel yea there's a bit more meat to them but you also have quite a bit of surface area with thread engagement which is what gives threaded caps their strength. i know it's not the best of comparisons but there's some similarities in function.
@@ToeCutter454 It's not just there more meat to them, they're designed to fail in a safe way. The RN-50 would be fine if they made sure that the cap was stronger than the barrel (either by having a stronger cap/locking mechanism or a weaker barrel)
@@Uryendel That's an interesting idea, but if the barrel blows up on a rifle like this it's still gonna do very similar damage to the shooter, I wouldn't call it "safer" by any means
I had been looking at buying an RN-50 from my LGS for a while. I bought mine AFTER Scott's blew up. Why? Because of YOUR immediate and calm response AND because of what I saw in the damaged breech end. The fracturing pattern in the threads showed clear excessive pressure. You build great guns. I love my RN-50. Thanks again for refuting the garbage others have put out about Scott's accident.
It was very clear from his response to the accident that he's the sort of guy you can trust. He was very concerned with finding out the cause and address it if there was a design flaw or manufacturing issue. The problem didn't turn out to be on his end, but it was obvious he was focused on finding out.
I would prefer a bolt-action or automatic .50, but seeing those threads hold themselves from a dozen mystery cartridges embossing their headstamp into the breech plug, that makes me confident enough to a box of proof loads with the thing without breaking a sweat.
Your intelligence on this matter is so much more powerful than internet troll opinions, just know, any person who is interested in this topic and knows anything about it, is comforted by your expertise. I would not hesitate for a second to buy a firearm from you. Bravo big guy
I hope to own a serbu rifle one day, the passion and practical knowledge you have is rare. I have worked with engineers like yourself and I learned so much in a couple years time frame. Good work!
Admittedly, I was one of those suspecting a design flaw when KB blew himself up. For me, it felt logical that when a gun fails, the mass between explosion and the user should be as big as possible and some obstructions (like enclosures) would reduce the force of shrapnel in case something goes wrong. It´s logical that the "ears" that were sheared off were the almost lethal parts that punctured scott. Thus, I found the comparison experiment with the M2 really good as it showed that this really doesn´t change things for the better, but adds other random factors to the issue. But that´s all besides the point. The gun blew up because the ammo was tampered/faulty and any gun would have blown up. As soon as the gun blows up, it´s rolling the dice if shrapnel goes your way and where it hits you. The "ear" could have missed or it could have punctured the skull.
Well said. Basically spend an extra 8k for a freak failure to be a bit safer… If can avoid the problem shouldn’t need the extra safety I suppose. Cost vs benefit.
@@carsonhunt4642 reminds me of ww2 german tank overengineering, i mean the designs were good and all ¿ but did they really need to add so much complexity and extra features when it would work just fine with much less? i really like their tanks and i can easily see they made a massive amount of bad decisions. Tho those bad decisions are one of the biggest reasons why i like learning about engineering in wars
10+ years in the industry…seeing an owner respond like this is porn. Truly amazing to see you come out and set things straight with facts. I need to buy your stuff now 👍🏻
Dont let em get to you Mark. Just keep doing what you do best. You are an inspiration. Ive always wanted to have my own firearms manufacturing business and you make me feel like it is obtainable. Keep up the good work.
It is pretty obvious from Scott's recent video finishing the last of the ammo box that an improperly loaded round was the cause. I recently blew a 7.2 ounce muzzle brake off a gun with experimental sabot ammo. It simply sheared off the thread adapter and went downrange into the woods somewhere. Recoil was normal with no damage to the receiver and no appreciable case head expansion or case pressure signs. It actually took a few seconds to realize what the downrange noise in the woods was and that the muzzle brake was missing. We can usually tell a lot from examination of what remains. Scott's experience was clearly an over pressurein the chamber event.
I argued the strength of the rn50 for several days after the incident... a whole bunch of people saying "I'd never buy one of these pipe bombs" and then I broke down the numbers for them & pointed out the fact that they would've never put down a deposit on a RN50 to begin with, so that just leaves more for the rest of us... 🤷♂️ Thank you for doing all you do, Mark.
@@rsh4599 that pressure max is so crazy to think about. If anything u would think that ppl would know it is a good rifle becuz it took over x3 the pressure to blow it up. I bet none of my firearms could take 3 times the pressure.
Ahhh Mark... I admire your courage trying to educate people that can't or just won't comprehend things, and who still think they know better about something you have mastered over the years. Seeing your struggle to explain things simply, I can only wish you luck for the future, and hope that you know there's still some sensible and more educated minds who know (to an extent at least) that what you're doing is far from a walk in the park and require a lot of work. Best regards !
I was initially in the sabot vs break camp, but I was in a gun store and had an epiphany. I was staring at a pre-WWII Reminton Auto-5 with a Cutts compensator. Shotcups are a lot like a sabot. Even if you were a royal fudd like my grandfather, who used a fiber wad and no cup for black powder skeet loads (sorry ghost of Gramp George, no, no, no, oh hell no), then you're really making it worse by shot column vs comp. We've been putting comps on shotguns for a century. If this was a problem, we wouldn't have noticed earlier. The only answer left is ammo, and bleed off holes for a 50 are going to be closer to a cutting torch than anything.
A break will never make a gun explode unless there's some reason the barrel has been completely obstructed lol, pretty sure that KB would have noticed this and whoever came up with the idea is an idiot
@@DickCheneyXX the argument was the sabot plastic clogged up the muzzle brake. problem is if that was true the muzzle brake would blow off not explode at the chamber
@@iceman5117 also the claim that slap shouldn't be fired through a brake appears to be nothing but Fudd lore. the guy knows the President of Barrett so if Barrett ever said anything he would know it. it takes a number of slaps to go through vehicle armor and hence a machine gun is far better for that then a ten round semi auto material rifle.
I'm actually convinced that the cartridge which injured Scott was *in excess* of 200000psi, because even the rigged cartridge meant to obliterate the rifle in his test couldn't do nearly the same damage. Looking at the test rifle also championing through the rest of those SLAP cartridges before that actually inspired a lot of confidence in me of the screw plug breech, because you've got those _crazy high_ pressures with most of the cartridges seizing up the breech something fierce, extraction was a project almost every time, and still the gun didn't blow or even so much as burst or bulge the barrel. I'll be frank and say that the RN-50 isn't a dream gun for me, but I'm also convinced it's an extremely safe rifle, few other guns on the market would tolerate the nonsense conditions it could go through here. I mean, will people call an antique Colt 1873 a death trap because you can Elmer Keith the thing with smokeless handloads? I wouldn't, and those guns aren't even drop-safe.
I think in many ways it's an awkward rifle, if money wasn't an issue I think it would be an odd choice, but agree that it appears to be very rugged/overbuilt
@@Wehra96 There's a lot of different things which could have been wrong with it. The powder could have degraded from bad storage conditions _(and according to some, these SLAP cartridges used a different powder from normal .50BMG ball which was less shelf stable, however true that claim is),_ along with it potentially being a counterfeit made with something like pistol powder, which itself could have degraded. Some suggest that it was a salted round, like Project Eldest Son, but I find that be less likely. Being a Cold War spy project thing, and such a specific one at that, it seems to me that it would be odd for it to pertain to a .50 BMG SLAP of all things, something which never got around anywhere with any enemies of the US or NATO, and then that cartridge would have to make its way back and onto the US. I really think that it's either a counterfeit which wasn't expected to be shot, or that it was a genuine SLAP but which had its powder charge degrade one way or another, the odds are just far higher.
@@tedarcher9120 using ears as safety check to ensure breach is closed would not work if you had essentially a quick change interrupted thread breach cap. Or you’d need to much more tightly tolerance the space between rear of cap and ears, which could interfere with the closing of the gun. A workaround I could see is an indexing detent on the cap that would only allow the gun to fire if the cap is rotated to the proper location, but then we are talking a more complex safety mechanism than just making it so the action won’t close until you have adequate closure of the breech cap.
I still feel that the rounds that were used were overloaded and dangerous. Too many people love to use heresy and innuendo without actual proof or facts, especially on the internet. You know what you're doing Mark and you stepped up from the beginning. I'd buy one o your 50's................ If I had the money, lol. Seriously, thanks for all of the videos you've put out and for addressing everything. Stay safe.
As non-native English language user: I always thought that "safe" and "failsafe" are 2 quite distinctively different words. "Safe" doesn't fail, "failsafe" fails but in the most safe way possible. Maybe I am wrong, maybe I'm making a mistake of translating English term back into my language and then searching for its meaning.
Something being "failsafe" means it's highly unlikely to fail But HAVING A FAILSAFE means having some sort of backup for when it does fail. I fully understand how this is confusing
Yeah, a failsafe device or feature is designed such that a failure results in what is most likely to be the safest state available considering the failure. So, for instance, at least one set of brakes on large commercial trucks and on railroad trains are designed to apply if air pressure is lost, rather than being unable to apply the brakes. Obviously, there will be situations where this isn't ideal(a single drum losing its air supply and overheating and starting a fire, for instance), but it is almost always better than the alternative of all the weight rolling freely. Another example is a lot of nuclear reactors will drop their control rods in place in the event of a power failure or if the control system detects issues with the coolant system, thereby slowing the reaction to a crawl and greatly reducing the risk of a meltdown. While there are probably a few situations where this would be less than ideal, I'm struggling to think of any atm.
@@1stCallipostle The OPs interpretation is correct - something that is *designed* to "fail-safe" is precisely that; WHEN it fails (failure is always an option), it *should* fail in a safe way. But reality doesn't always agree with your design. Something that is safe cannot cause harm; if it can, then it's not safe, *but* we do often use "safe" to mean "very low risk". (E.g. "safe driver" - driving is inherently dangerous.)
@@spudgamer6049 and that's more or less what the ears are for on the RN-50. He designed it to take like 150 percent of rated pressure and the amount of force to SHEAR those off is incredible. The powder obviously burned far too quickly so he had a small explosive in the chamber.... ouch.,
@@ExarchGaming I disagree. When/if the design fails, it fails in a fairly bad way. It just is designed not to fail except under extreme circumstances. That's different than being designed to fail in a safe-ish way. Not saying there's anything necessarily wrong with the design. You can only realistically design for what is within the reasonable realm after all, and I'm not sure that there are any particularly good ways to make a 50bmg chambered gun fail in a relatively safe manner that doesn't compromise it in other ways. Maybe those ears could be made strong enough such that something else would give before them, but I'm not sure how heavy that would make the gun, or even if that is realistically possible.
I had doubts about the gun at first but after seeing so many gun influencers showing the capability of this rifle. I fully back this rifle. For those rounds that KB shot I did some research and found out that even when those rounds where being manufactured, they where still a bit dodgy during production. They took years to perfect the round and they knew the exact specs required to make that round reliable. After finding out that he purchased those rounds online I just thought “someone who probably just knows the basics of the .50 BMG rounds. Not much in the lane for the specialty SLAP rounds.” The gun still has my full support. I can see it in my safe down the line from now. And I look forward to it! Great gun love your videos. Keep spreading the knowledge
Exquisitely eloquently stated. I haven't heard such a perfectly preformed take down of ones detractors in quite a while. Said with passion and love for what you do and explained everything in such an easy to digest format. It was very organic and well said. I look forward to watching more.
It's funny Mark mentioned being less safe by trying to be more safe. The 1st Generation Dodge Viper is kind of an example of that. Back in the late 80s, there was no traction control system or stability control system. The driver's right foot was the traction control system. The driver's hands on the wheel was the stability control. The 1st Gen Viper had very wide tires for the day (and they're still wide today) in order to give it lots of grip for that monster of a motor it was carrying. And it worked! The Viper had a ton of grip, but it was also kind of a problem. You see, you could use all that power and get going really fast indeed, but it also meant that once you crossed the limits of traction, you were going really freaking fast when it did let go and chances are that most drivers didn't have the skill to bring the car back in line. Issac Newton was in the drivers seat at that point and you hoped that Chrysler's engineers built a safe car, because you f***ed around and were about to find out.
having spent several years driving an early viper I can tell ya that when you finally exceeded the grip / handling limits - there was lots of flailing arms, swearing and sweating and the eventual change of underwear and stiff drink hahaha , that car forced you to concentrate 110% of the time when driving it, even if just popping to the shops... But it was such fun and a very rewarding car to drive, even if my ears didn't agree with my choice of straight thru side exit pipes >_
Scott from Kentucky Ballistics did a test with 3 rounds, the first with a normal powder charge, the second with a 1.5 times powder charge and the third with a heavy double powder charge. It was the third round with the heavy double powder charge that blew up in almost exactly the same manner as the first RN-50 that almost ended him. Scott followed up with a second test with a new RN-50 and a new round with a heavy double charge. Again the results were almost identical to the first one that blew up on him and the first test rifle. None of the rounds he used for the tests were Sabot rounds to eliminate that as a factor. His conclusion was that he used rounds which he could not verify were factory loads. His new policy now is to only buy rounds from sources that he knows and trusts. It wasn't the gun that was faulty, it was in fact bad ammunition.
Well said. It's like putting a 400 shot of nitrous into a 4 cylinder grocery getter. Even if you can get it to not extinguish the plugs, it's not going to last very long.
this doesnt change that the RN50 has unsafe points of failure, the cap is its main weakness and any failure in the cap will result in it being tossed at the shooter as shrapnel, an easy way to fix that would be to design the chamber walls such that they were still strong, but weaker than the cap, so that any round loaded normally still fires normal, but dangerous overpressure would rupture the chamber walls, venting pressure to the sides, where, on a safe range, noone should be standing
The RN-50 is an amazing weapon and a great price to get into a 50cal. I’m not scared at all!!Something that finally failed at 400% capacity is about the best advertisement you could get for a firearm.
The amount of people who don't understand that a bolt action is just interrupted threading is astounding. And that complete threads are going to be stronger.
I didnt know anything about that and i also dont have any thread knowlege. That being said, without any knowlege of that stuff, i always though a bolt action was safer compared to that breach cap just by the look of it. Its like judging a book by its cover, its ok to do it but don't go around spreading potentially miss information about the subject to anyone.
Depends on coarseness and depth of threads. Yes artillery is interrupted thread breach but very coarse and deep. A bolt on bolt action even one with 9 lugs is not interrupted thread it is similar but not interrupted thread. And much stronger than medium to fine solid threads.
Brother I had only heard of your brand with no experience with it. But after all the videos I've seen be it forgotten weapons, or even Kentucky ballistics themselves I want a Serbu 50 about as much as I want anything in this world. It's affordable already but after all the tests I've seen they have to be one of the best made period. Mr. Mark you make a great product but most importantly from all I've seen you're a good man and wish you nothing but continued luck and success.
As a machinist and someone who has worked on all types of metals for all sorts of things, I know for a fact that cap is no joke. I also know whatever can blow it off is no joke too lol.. Lot of guys here and on KB's comments who obviously have never worked on any metal in their life trying to act like they know everything about threads, metallurgy, pressure loads.. I'd ignore it. Like you said, too many people here just want to be heard and want to pretend they're better than someone else for personal brownie points
Absolutely right. There’s no way in hell the sabot would get stuck enough to blow up the gun under normal pressure. People who believe that are probably thinking about guns in movies, or those old-time shotgun barrels made from fused sheet metal. Modern, proper firearms made from quality materials are really brutally hard to create a barrel obstruction severe enough to blow up the gun with. Threading the inside of the barrel and screwing in a 2-inch bolt can do it, but less than that is unlikely to make any difference. I’d shoot the RN-50, no qualms. As long as the ammunition is verified as standard-issue and within tolerance of the weapon.
It’s definitely written in military manuals and other manufacturers 50cal. Manuals for a reason. They usually don’t just scribble in “beliefs” in those things.
@@brianjames8600 Be specific. Exactly what do they write; “Don’t use sabot rounds with a muzzle break” or “Using sabot rounds with a muzzle break can obstruct the barrel enough to blow up the whole gun”? Because there’s a difference in intent and breadth of consequences. Do you have these manuals and instructions handy to quote them word for word? If you can, please do, as it would be interesting to see the way they formulate it.
Man I can't imagine having a company and dealing with an issue like this. With how people are so willing to internalize their first instinct and then dismiss anything that could challenge that thought, really fighting an uphill battle even if you are completely in the right.
I am not dismissing new evedence, but I don't think the owner of the company should be labeling potential costomers as stupid for asking more detailed questions.
One thing that I've wondered since then: if the threads had held for that round, what was the next failure point? Imagine if it was fragments of the firing pin assembly, heading straight back through the shooter's torso?
@@wilsonrawlin8547 It's also possible that, with enough pressure, he could have simply split the barrel back by the action. Which would have had a nearly identical effect.
Scott himself said that it wasn't the fault of the gun. The really hot, overcharged ammo (presumably tampered) was absolutely at fault. Threads like that do not fail unless you seriously overpressurize the chamber. He just got super unlucky. Anyone claiming that something got stuck in the muzzle brake is wrong and clearly hasn't watched Scott's follow up video when he re-tried the test. He went through all 12 SLAP rounds and it didn't blow up. It took a round that he specifically massively overcharged before it actually blew up the gun.
@@toomanyaccounts correct, they're all kinds of counterfeit slap rounds and the way to identify them is they do not have a crimp, their primers are usually brass colored and not nickel colored like real ones, fake ones usually do not have the primer sealant present like the real ones do, and on the Sabot, fake ones do not have the little cuts on the top to aid in splitting apart to release the projectile.
I will be 100% honest boss. I immediately wanted your rifle because of the Kentucky Ballistic accident. In his recreation video, I was floored at the amount of abuse that rifle took. Such a great design!
In a video from not too long ago, Gun Jesus discussed that any firearm design has to be a compromise between firepower, weight, cost, and durability, and a few other things. Many of these factors are directly opposed to one another. Weight and durability are a great example: If durability is your main goal you are going to have to compromise on weight, and visa versa. The take away is that there is no one gun design that can do everything "best", it's always a balance of compromises. Mark, for what it's worth from a stranger on the internet, I think you've handled this incident really well. You have been transparent and communicative, not hiding behind PR and legalese. Scott from KB seemed more than happy with how you worked with him, and that's the most important thing to me.
@@reliantncc1864 What's the saying about Marines? Put them in a room that has no doors or windows with a steel sphere for 24 hours and they will have broken the sphere, lost it, or impregnated it? Something like that. (Not hating on Marines, just a joke.) Doesn't matter how "safe" something is made, some idiot will find a way to unsafe it.
The genius physicist/ metallurgist/engineer ,Matt at CRS firearms , jumped on the "unsafe" design band wagon and even showed in his "expert" what you should have done.
@@cberge8 I also unfollowed that douche nozzle because I can't stand people who know absolutely nothing about a particular subject , except for a Google search ,then give"expert" advice on that subject. It would be like giving a brain surgeon tips , because you watched a film in biology class about the brain. Matt's apology was a hollow gesture and CYA. He used his platform to trash a Guy and his product , that he knew ABSOLUTELY NOTHING,about then say ,oops my bad ,sorry.
Very informative discussion. I am a Mechanical Engineer who enjoys all your videos. I never was scared of the RN-50. I am still awaiting the full release sale of the AOW RN-20 Mike Mike (20 mm Vulcan Rounds with explosive primer's. I believe the 20mm rounds can take 50 BMG primers. I bought some 20mm rounds from a well-known reloader but wound-up reselling them with the 1 ea. 20mm Vulcan barrel. The hard-to-find part to make a cannon is the breech. It is very difficult for just some guy to put together a 20mm cannon. Barrels typically come with interrupted threads which typically fits nothing anybody has laying around for that rainy weekend project
I will reiterate: My opinion, as an experienced, trained engineer that also shoots... Is that Mark's design is solid. Accidents happen, and I believe the ammunition caused this one. I don't see where suing Serbu is beneficial to our hobby.
I think that the gun may have been i micro bit weaker than the new one since he shot it before but it would be neglible. So all the fault was on the slap rounds. Sry for bad english im a swede.
It’s obvious it’s the ammo but the gun design fails catastrophically for the user. No other 50 on the market would fail so dangerously given that same round
Hi Mark (metallurgical engineer here). All of these analysis videos are excellent, keep it up! One detail I would like to correct you on, though. Yes, the stress-strain curve will change shape with different grades/heat treating of the steel ears, and making them bigger will increase the magnitude of the curve on the stress axis. But making the ears "stronger" (strength generally means the peak stress value on the curve) does not make them move faster when they shear off. The burning propellant converts a finite kinetic energy to the cap when the threads finally let go, and the area underneath that stress strain curve represents the amount of that kinetic energy dissipated by deforming the steel. The more energy dissipated by deformation, the less energy available to accelerate the ears AFTER they shear off. Next up, we gotta talk about how Time-Temperature-Transformation curves set the rules for what you can heat treat with that induction heater...
I’m a mechanical engineer though I always gravitated towards thermo rather than materials. I can definitely imagine a situation though where the deformation isn’t plastic in most of the ear instead storing energy due to a bending force and when the ear breaks off that energy is released, snapping the ear flat against whatever broke it off thus shooting the ears off faster than they might’ve otherwise gone. Like those poppers you’d play with as a kid, turning them inside out and waiting for them to pop out. Would that be an unreasonable analysis if the ears had defined areas of acute stress where they snapped and the rest of the ear experienced it’s own bending force? Edit: also worth mentioning that the cap doesn’t stop being pushed/acted on by the explosion until after its already launched those ears to kingdom come
I have always doubted the "plastic sabot stuck in the muzzle brake" theory... Plastic just simply cannot hold that kind of pressure without giving way.. I have seen copper bullets of the entirely wrong caliber get swaged through a rifle bore without any damage to the receiver or bolt... I still think those s.l.a.p. rounds were loaded with too fast of a rifle powder.. Or a pistol powder... Pistol powder in a rifle will cause big problems!! But that's just my thoughts on that situation... Love ya Mark! Keep em coming!☺👍🇺🇸
Pistol powder in a rifle is great for cast bullets. But it's also way too easy to overcharge a case with the tiny amounts of powder that are used, so you have to really be paying attention while you're loading. It's possible the same kind of thing happened here - they used a regular rifle powder when a slow-burning magnum rifle powder was needed, and ended up doing a double or triple charge.
Mark your a good man for deep diving into Scott's accident! IMO I believe almost everyone believes that the round it's self was incompetently and egregiously overcharged with powder I believe that you provide a phenomenal product and that the accident had nothing to do with said product but you are good man for your diligence sir!
I think Scott proved that pretty conclusively when he (the madman!) fired the rest of those rounds in a much later video. Those were definitely spiked rounds.
Mark, I’m an engineer and you are living through my second worst nightmare (I’m sure you can guess the first). I’ve followed this since Scott’s video went up, with multiple perspectives. I want you to know, you did good work. You produced a safe product, given every reasonable situation. Scott’s videos show how over-hot those SLAPS were loaded at, and the one that exploded was WAY over pressure. I wish Scott had saved the rest for a powder analysis but we can’t live in the past. You are a good designer, and the fact that this upsets you shows that you are a good man.
Thanks Mark for keeping everyone in the loop,I own one of your RN50 before the KB accident was shot before and since,being a heavy equipment mechanic I truly believe in threads,bad accident,bad round,gun not at fault.
Mark is awesome and transparent; this is why after I receive my first RN-50 I will order more. If Mark is confident and has the receipts to back it, I will trust him with my life and others.
Just throwing this out there for some food for thought Mark and curious watchers. When I was in combat in Iraq we got tasked to actually implement spiked ammo into the battlefield ( enemy ammo calibers of course). It's a highly effective way to have passive attacks on the enemy, break up enemy moral, break up enemy supply trust, etc... As far as I know our RIFLE ammo never was spiked enough to kill but meant to destroy the weapon first, and have slight secondary injuries just as a bonus. Most times just a destroyed AK, RPK and some scratches and cuts on the hands and face/ eyes. We did have lethal stuff too but that was for mortar and artillery shells that got used for making IED's. Those weapons were tracked and could be detonated on command (very interesting tactics can be implemented with these babies). When you start talking bigger caliber rifles and machine guns like DShK's and NATO .50's there really is no safe way to destroy those weapons without making them highly likely to kill the user. It just is what it is...Make no mistakes about it though, the enemy was doing the same thing to our ammo. Hardly ever happened to americans because we hardly used battlefield pick up weapons and ammo. It's very easy to use this tactic on guerilla elements because they use what they can get most times... Saying that, there is alot of people that re sell weapons and ammo from conflict zones where these tactics are being used. Unless you are apart of the team that spiked or left the ammo on the battlefield theres not a great way to inspect and know which ammo is spiked and which is normal ammo... I would recommend never buying boutique ammo off of sites like Ebay.
I call BS on your whole story. This is the first time I've heard of the US doing this since Vietnam. And who in their right mind thinks you can buy ammo from eBay?
Mark, I deeply respect you for your handling of the absolute tsunami of opinion people have thrown at you regarding your design. The design of your gun is not what made the KB incident happen. And you are completely correct when you said, "There is no such thing as a fail-safe." Anything can be made to blow up if enough explosives are put in it. That bullet that blew KB's gun apart would have decimated most guns it was shot out of - regardless of their design.
I thought the consensus was that the slap round had improper powder, and it caused an over pressure in the chamber. First time on your channel sir, kudos for the analysis. Keep building amazing arms!!
"Fail-safe" does _not_ mean "cannot fail" -- it means that _when_ it fails, the failure mode will be SAFE (rather than dangerous). One well-known example is the "crowbar circuit" which creates a short circuit to force a fuse to blow in order to prevent catastrophic damage to the power supply when a failure occurs.
some people seem to use fail-safe without considering its meaning, they may mean the chance of a failure or unsafe condition is exceedingly unlikely another good example, glider training operations. the braided kevlar tow rope always had two weak links made of poly rope, if a strong thermal comes, truck is too fast or the pilot is climbing too much, or somehow the glider cant pop its release. weak link pops and prevents airframe, tow vehicle, or expensive haul rope damage, and just becomes a small pain in the ass for the pilot to modify his flight, and for me chasing the rope through the swamp.
Exactly! To Mark: As an engineers we want REDUNDANCY in safety measures, that is what "fail safe" means. Measures that are destructively tested to prove they work as fail safes (aka redundancies). Personally you should probably listen to "gun jesus". He just might have some knowledge you lack. Screw caps are barely considered adequate on sub-guns, much less 50 cal bolt-action rifles. And the whole "heat treat it, yeah..." comment.... for F's sake hire a materials engineer and/or metallurgist if you make a 50 cal Bolt action. Don't tell us "heat treat it yeah..." And larger, more-secure "bigger things" (i.e. safety mechanisms) "flying off" would "fly off" exponentially slower... and would not "cut your head off". No ones "trolling" this man, but he sure loves to blame the internet when his gun blows up.
@Hornet135 Of course it can never be 100% safe. But it will significantly improve safety by a magnitude. Look at crash tests on cars. Imagine if they gave up in 1930 and just said "fuck it, car crashes occur with too many variable let's just give up on making cars safer." Instead they made fail-safes called crumple zones, which Ian says is similar to the arisaka vent holes and safety cap which are made to redirect energy away from the user. With enough energy of course these safeties will still hurt the user. But now you need a hell of a lot more energy to hurt them.
Mark, Indeed it was bad what happened to Scott. Love both of your channels. When I watched Scott's video of the Rn-50 blowing up on him. Not once did I say the gun was at fault. Myself, I am not an engineer, Yet I am a mechanic that hunts and reloads. Lot of experience with things that goes boom and blowing up stuff also. The very first thing I thought of was, That round was over charged by or with the wrong powder. Or it being old, the chemical change with time made the powder a lot more volatile than normal. Also, for the record, I do have a place set aside in my gun safe for an RN- 50. Just do not have the land yet to fire one.
Folks are something else. K.B. showed and explained it was the ammo. , Then the ES video with the barrel embedded in concrete showed the craftsmanship of the firearm. Keep up the great work. Awesome video. Don't stress the trolls
Just some fun things to think about: Gunpowder is not supposed to explode under normal use. It is meant to burn really fast, but not so fast that it counts as an explosion. It may all seem instantaneous to us, but there is a big difference between how fast pressure rises when gunpowder burns versus explodes. So, designing for handling an over-charged cartridge is not the same as containing an explosion, and no gun manufacturer plans for their gun to have an explosion in the breech. Large caliber revolvers are some of the more common recipients of ‘oops, wrong powder’ explosions that I know of. You average revolver has all the gas venting you could possibly want with the cylinder gap, and the clearance behind the cylinder. It’s about as ventilated as a chamber can get. They still can’t vent enough pressure to keep from blowing apart when enough fast-burning powder is in the cartridge to cause an explosion. I’m general, the chamber will split in half lengthwise and get launched into the top strap hard enough to bend or snap it. This tends not to be deadly as most shrapnel goes upward, but it does fuck up peoples hands pretty bad sometimes. The ears on the RN-50 are already much stronger than the part of a revolver frame that would keep the cylinder from blowing back into your face, so I don’t think making the ears stronger would be very helpful. If anything, the chamber on the RN-50 is too strong. If you put a relief cut on the side of the chamber so that, if the action does fail, we know it will blow out of that area, like we know a revolver is going to crack the cylinder in half and launch it up into the air, maybe that could help? Nothing is going to keep a gun from turning into a bomb if there is an explosion in the chamber. The best you can do is try to make it blow up in as predictable a way as possible. So, if there is a problem, it isn’t that the gun isn’t strong enough. It is that it is so strong we don’t know exactly how it is going to fail when someone puts a bomb in the chamber!
![เบิ้ล ปทุมราช - อ้ายกินดอง น้องลาบงัว ft. สแน็ก อัจฉรีย์ [OFFICIAL MV]](http://i.ytimg.com/vi/-OK--KaSPcI/mqdefault.jpg)
Certainly wasn’t expecting a mention… and I was still laughing at Edwin’s antics when it came up!
Anyway, re: the KB incident, if your previous videos didn’t convince people that your design will not fail under (anything approaching) normal use, I’m not sure anything will. It sucks that you need to defend your good name.
How unexpected. Nice to hear from you my family likes you're channel.
and KB did a video it as well and its seems a lot of people in the comments haven't seen it and KB did it with a barrett the gold standard of 50 cals and it blew up just the same.
You're up there with Project Farm in regards to trusted reviews.
I was surprised but you hang out everywhere
Whats up LPL. Good to see ya
One of the most telling things about this whole debacle is that I've only heard criticism of the design come from non-engineers. As an aerospace engineer, we don't design for margins anywhere near what you do, so when I hear that the action failed at 400% of the cartridge spec it's amazing to me that it got that far. Nobody expects you to be able to take a Honda civic and flow 10 kg/s of nitrous through the engine without catastrophic failure. Guns for so many people in the community are just strange magical blackboxes bullets come out of and God forbid if you remind them they are machines like any other.
Not an engineer, but when reviewing pressure tanks that exploded, the one part always intact was the threads. Just seemed like common sense that threads were always a stronger connection in pressure situations than lugs. Wish the so-called TH-cam-experts would have discussed that and shut down some of the hyperventilating about a threaded breech.
I fuind it amazing how the stoner ar design was great BECAUSE, a aerospace engineer designed it... imagine how great an airplane would have been if designed by a gunsmith?
If all guns were designed for the absolute max compressed load of the fastest burning powder available for the particular round chambered, you can bet the farm that the same complainers would be boohooing about how heavy and massively overdesigned the weapon is.
Why does my 300 winmag have to weigh 20lbs stripped?
On the flip side, thinking about consciously putting your face mere inches from an explosion with tens of thousands of PSI's of pressure to simply expel a small bit of metal in an intended direction isn't something that everyone really wants to think about.
@@jackdundon2261 You mean the A-10 Warthog? :D
A man almost died. Regardless of any factor, every single thing related to that accident requires in depth analysis. A lot of companies, once they realized they were clear of a lawsuit, wouldn't have given two fucks. The fact that Mark himself cares enough to dedicate this much time to the incident after the fact really says a lot of positive things about the company.
This is where I was going to go with my comment. Mark is going way beyond the call of duty with his continuing analysis. I would suspect he donated the testing guns to KB for his destructive tests. Edwin mentioned he was sending his back to Mark after his concrete testing, I’d bet Mark ate that one as well. If I had a desire for one I would not hesitate to buy and use. I’ve shot 50’s and I don’t see any practicality in it for me.
@@kinzieconrad105 ....and water under high enough psi can cut steel.... le gasp......
@Kinzie Conrad
Did you not even watch the video? They buried the barrel in 4 feet of concrete and it still didn't break the threads, you're an idiot lol
@@ISAFSoldier Not just steel, scary ceramic too!
It's also great material to educate idiots with. I have serious respect for Mr. Serbu
I'm a bit flabbergasted how people thought a piece of plastic had enough tensile strength to withstand enough force for the back of the gun to blow up rather than the plastic. ON WHAT PLANET IS THAT POSSIBLE? - ok watching the rest of the video now.
Would star tracks plasteel do that
@TheGunCollective You also have to wonder how every shotgun doesn't blow up from the plastic wad that's shot through EVERY time it's fired!
@@markserbu Even worse: Shotguns with chokes. D:
Honestly, people making these comments likely didn't watch any video on the matter to the end, and have invested exactly 0 seconds into thinking about / reading into materials science.
Exactly what I thought from the very beginning! It had to be something other than the proper powder loaded in that round. Glad Mark is vocal about this and calling out the stupid “dog bark”ing people and their comments.
Most people are dumb...They don't try to understand the physics behind something and they make up what reasons they think work best instead of actually listening to engineers and other S.T.E.M. qualified people that can explain it through math and sketches.
As for the younger generation ..we've seen so much dumb shit online we can spot a troll most of the times.
Sketchy ammo was to blame. I am a fan of Serbu. Keep designing and building. We need more guys making new stuff.
I am a fan of Serbu, and I agree that we need more experienced gunsmiths making new stuff.
Even Scott talked how old the ammo was and that is wasn't produced anymore and also said he did not really know how "hot" the rounds were.
I'll be working on a gun soon
The problem with surplus of unknown storage and transportation history, some could get exposed to excessive heat and/or movement, degrading the inhibitors, greatly increasing burn rate.
Sketchy ammo doesn't excuse poor safety design
I find it “funny” that even though Scott himself said the gun was not to blame people went out of their way to make assumptions and call you/your business out based on nothing but speculation.
Scott suffered a seriously traumatic injury and lost enough blood that he can't really be considered Scott anymore
@@macbook802 he ain’t a cyborg
@@manbaby9166 New Kentucky Ballistics Mascot be like
Scott-borg, a man of steel and heart who has come from the future to stop evil inflatable dinosaurs and eggplants
I think part of it is the design already sketched a lot of people out. Tbh before all this I saw the rn50 and was like fuck no, that things like a fucking factory made pipe gun, I don't trust that not to become a factory made pipe bomb in my hands. When KB happened i was like "it was only a matter of time". Ironically in the long run it took it blowing up to convince me I should get one. After having seen all the testing I'm a lot more confident in it being safe and fun to own.
@@Badspot Dude, take off your tinfoil hat.
Mark, I'm happy to see you addressing this stuff in its entirety. Big respect for attempting to cover all aspects of concern.
What is failsafe? You cannot prevent failure, but you can make it fail more safely. For example, if the top of the barrel was intentionally made weaker than the cap, then the rifle would blow-up upwards, instead of blowing-up in your face.
Anyone who's taken a physics course, or a materials course... and passed, knows that the pressure required to rip the threads off even a grade 5 bolt of that size is phenomenal. Mark builds a good gun. I just got my new Serbu 50 cal and shot it the first time last weekend... not a worry in my mind. Keep up the good work, Mark.
Obviously everyone who's talking shit about the gun doesn't know anything about engineering and design. A part (can be just a beam of steel, but here the gun) has to withstand certain forces. It shall be designed in a way it's safe for normal use. For mistakes and stuff the part can usually withstand around 1.5 times the normal force. Beyond that, it's not the designer's fault.
You forgot to multiply the thread load capacity by the 2 fucking 1/4" steel backers behind it that the cap completely sheared off like they didn't exist. People are just ignorant. I don't know where the 200k psi rating Mark threw out came from but it seems a little low to me. To move a cap backwards fast enough AFTER failure to sheer off that much steel, it had to be SIGNIFICANTLY over the failure load, not just slightly. If it was slightly over it would have dented the steel and then deflected up.
All BS aside, the RN50s rep took a beating in the court of public opinion. I could not imagine anything more infuriating than being judged on something,that the firearm was never designed for,by a bunch of people that know just enough to sound like they know what they are talking about.
Carry on Mark.
Thank you for doing all you can to educate the masses.
It has taken him like a year to get to the point
@@CAMSLAYER13 The ammo was in question from very early on, it was determined it was the slap rounds mere weeks after incident happened, it was covered by marked himself then not long after that KB destroyed another RN 50 to demonstrate the forces needed to destroy the breach cap as well as the lugs that everyone likes to get philosophical about.
Truth is nothing would have survived that,… there was a dude not long ago that loaded a tube mag shotty with questionable ammo… it chain fired the whole mag disintegrating the fire arm and indeed his own arm. Now , do we demonize that model of shot gun because of the incorrect ammo, or,as animals equipped with the powers of deduction, rather than flock mentality, do we identify and remove the greater hazards?
Mark is clearly annoyed and rightly so. Half informed critics are as useless as biased ones.
@@riz3nfpv306 He has every right to be upset but, unfortunately it's the way it is, the damage done cannot be reversed.
Sucks for him, but the gun has a bad reputation now. KB's video will always have more views than any of these video's, only very few people in contrast will see any of the breakdown videos.
@@kinzieconrad105are you saying it blew up because of the threaded breach cap? Do you think an m4a1 would have done better ? Get educated bud… or be one of the guys we can laugh at
@@Chzydawg I don’t know which are dumb and which are dumber. The ones starting the BS or the ones Taking it as the truth.
It actually is saddening, you need to remember producing an item to supply to the public is a difficult enough task. You guys are blessed to have guys like mark in your country to design and supply these products. Also the birth of the RN50 was to supply a need in the market for a budget 50 cal…he listened to that need,why tear him down?
If a guy like mark comes under scrutiny from his peers in his community, and is found free of liability, he should be supported. Not continually dragged through the mud
Ok fair ,in the name of safety - IF the gun was faulty sure get it out there - but it’s not , why keep up this fallacy or misinformation? Why not go after the guys that supplied the rounds?I don’t get it.
From the test that Kentucky Ballistics did, someone tampered with the SLAP rounds that he bought, and loaded them way too hot. The ammo was to blame, not the rifle.
When you obtain ammo that has never been offered to the public, what is available "fell off a truck somewhere", you are taking a very big risk especially considering the price these rounds bring.
how much extra powder can a .50 BMG case hold?
@@ZE0XE0 enough to blow up a .50 cal rifle apparently
@@aethelon4144 No, it had to be the wrong powder. Even a compacted load in the .50 wouldn't cause that serious of an over pressure, it was most likely pistol powder.
@@ZE0XE0 The burning rate of the powder used is very important, faster powder as used in pistols is less dense than slower powders used in rifles, a case full of fast pistol powder could be responsible. Or something other than gun powder inside the case.
Thanks' so much Mark, this was great info I didn't know. We shoot a lot of SLAP rounds on our channel but were only going off what everyone else said as far as muzzle brakes go when we first started shooting the SLAP rounds. At first, we were shooting them with the brake off, but the dang thing kicked so much Justin made an insert (basically a machined tube with a bunch of holes in it) for our Bushmaster BA50's big old honking brake and it works just fine. Thanks for the common since showing the footage of the rifle blowing up, and one no in cement. It doesn't much clearer than that.
@Going Ballistic Thanks! As pretty much everyone knows, the plastic sabot *can* damage a muzzle brake. In extreme cases, pieces can be blown off and fly backwards at bullet speed. Hell, in the prototype phase of the BFG-50A we had brakes lose some pretty big chunks, and that was just from propellant gas! Excellent idea with the perforated tube insert!
@@markserbu thanks for the response, I’ll send you a picture of our insert. I would like to get you take on it.
Chris
Been following along from the beginning. As a Mechanical Engineer (now retired) specializing in Forensic Failure Analysis for over half of my career, I find it fascinating the process you have gone through to this point! There's an old saying: "The Devil is in the details".
🤔
Can't imagine any other creator in any other industry being as open as Mark
If I was in the US I'd definitely give him some business
Same here @David Hughes!
I can see how uncomfortable saying some of this is making Mark Serbu!, and learning internet culture where Keyboard Warriors can verbally assault people who they wouldn't fecking *DARE* to mouth off face to face is a lesson that can be hard to learn!.
Fair play to Mark for his openness!... As for Failsafe, I.E. PROOF-ing *anything!* a great *Old* saying is it's hard to *FOOL* -proof *ANYTHING* because they just keep making more ingenious *FOOLS!* by the way that's not a dig at *KB* ,I think Scott is cool as feck!
Keep your head up and keep doing your thing Mark!
I want to see a knock off version of RN-50 by Hi-Point or some other low-end manufacturer from China or Ghana or Peshawar....then we can look forward to some real carnage.
In the US, "giving someone the business" has negative slang meaning.:-)
@@hueyiroquois3839 What does it mean then, besides the literal meaning?
It means giving someone a beating.
The only thing that scares me about my RN50 is the thought of carrying it more than 20 feet. And firing more than 10 rounds in one sitting. Fantastic rifle and the most cost efficient method of delivering 50bmg to a target.
10 rounds in one sitting, what hurts worse. You? Or your bank account? ;)
@@bananadad9228 yea a 50 caliber is fun and all but shooting 30$ downrange in a few minutes starts to hurt when you think about it
@@jacobkudrowich The only difference between men and boys is the price of their toys. If putting 30 bucks of ammo up in smoke bothers you don’t ever own/shoot a machine gun, Gatling gun or shoot rifles chambered in most classic “dangerous game” cartridges. This is why traditionally most metallic and competitive shotgun shooters reload their own ammunition. For me and many other shooters who reload their ammunition it brings another element of enjoyment to shooting sports.
The only thing that scares me about shooting .50 BMG to begin with is the entry fee: buying the gun and a reasonable stockpile of ammunition.
@@drrocketman7794 I've got about $3100 tied up in my RN-50 plus 700 rounds -BUT- I hand loaded all my ammo.
You are 100% correct. I’m a retired engineer and I know that what happens at the muzzle brake can not cause the chamber to fail. The muzzle brake is the weakest part of the weapon, and by the time a projectile reaches the brake the chamber has already reached and passed its maximum pressure.
Also the fact that there was no damage to the barrel, no expansion or peeling, proved that as being wrong. The barrel is strong, but it would be an extreme oddity for a barrel of any kind to be stronger than the chamber. The nature of gun design alone makes that unlikely, and the fact that the barrel is threaded into the receiver which is providing additional support for the chamber.
It was clear to me from the first video of the explosion that it was a massive over-charge, and when things exceed the expected worst-case possibility design, it is impossible to predict the outcome.
I own a Mark Serbu designed 50A rifle, I’ve had many conversations with Mark and his staff, smart people, great accuracy and I shoot my own reloads. 3 rounds touching at 300 yards. Hang in there Mark, this to shall pass.
@Scott McBride Thanks! One of the funniest things I read on the internet some time back was that Valerie Serbu designed the BFG-50A!
@@markserbu It’s crazy what you can find on the Internet.
Kentucky’s blowup, from the perspective of a reloader, looks like classic overloaded round. Barrel obstructions USUALLY banana peel the barrel, not blow the back of the bolt/chamber open. Especially seeing him fire the rest of the ammo from that batch he bought, almost every last one gave clear and loud warnings of a hot load.
Whether the failure mode of the RN-50 could or should be different is another conversation, but the ammo caused the blowup. I’d bet a not inconsequential amount of money on it.
A little stupid thing that some ill educated gun nuts do is clean and shine their loaded brass in a vibrator , a big no no, you literally remove all coatings off the powder and if it's double base powder you quite literally have made a very destructive instrument, can't say the word TH-cam won't let me , video creators can but commenters cannot.
What about his blowup doll now
As seen by his other demo tests of guns, there's not really a design out there that would be much safer than the RN. The Barrett is the gold standard .50 and that thing would've still likely killed him
I could see that as well. In all of the pictures I've seen of obstructed barrels being fired into, there was ALWAYS at least a bulge starting near the obstruction point, and very often splitting. It's the thing every reloading manual has warnings about. An over-charge can cause excessive wear or binding on the action and a massive over-charge will blow out the action. The pressure spikes too high before the bullet gets out of the barrel. The fact that all but one of those SLAP rounds were over-charged to an extent is plenty of evidence that one or two could be explosively so.
When you're hammering, or otherwise using tools and force, to open the action, your rounds are too hot.
Except on a Mosin. Hammering is expected.
@@Robert-qm7yi This was my thought as well.
That pressure wants to go somewhere, and if it's going anywhere but forward, there's a good chance you're going to be on the receiving end of whatever that pressure is dumping it's kinetic buildup into.
Be it the end cap and lugs of the gun, or the remains of the receiver folding over backwards into your face. At the end of the day, you're sitting inches away from a contained explosion that's almost _four times_ the rated pressure of the rifle, at an already extreme pressure rating.
The only way i see to account for that is to over-engineer the hell out of it and hope it doesn't fail, because at those kinds of pressures, no failure mode is going to be pretty.
EDIT: Forgot how fucking insane the pressure actually was, just looked it back up because i wasn't sure.
I still can't believe Scott's alive.
Regarding "fail safe". This is like when people ask locksmiths for locks/chain that will stand up to an angle grinder cutoff wheel. **Nothing** stands up to a cutoff wheel.
"Okay so we sell this hardened security chain by the foot, right?"
"Yeah..."
"How do you think we cut it to length?"
"... oh."
Totally right abrasives are the way to cut the hardest material most people have no idea how to cut what with what properly
(In Beavis' voice)Uhhhhh, cutting torch?
Or the people that want extra screws in the deadbolt I their front door......that has windows on each side.
If it's really tough it might take more of the wheel to cut it but it WILL cut it. 🤓🍻
@@mephInc Surely the criminals won't take the path of least resistance... surely...
Of course, depending on how high said criminal is, ya never really know!
The way Mark has handled this-- and this video in particular-- really inspires confidence. I'm an engineer and gun enthusiast and all of Mark's remarks have my engineer brain nodding in violent approval. There's no such thing as fail-proof. Just fail-resistant. For example, I can layout some hydraulic hoses with different sized ends to make it only go together one way, but a trip to the local hose shop for an adapter and just like that it's plumbed wrong.
Mark's analysis is spot on, and it shows a dogged determination to vindicate his design-- which I sure as heck would also want to do if it was MY rifle that ignorant people were accusing of being at fault.
The whole "sabot plastic is getting stuck in the muzzle break" thing is easy to disprove.
Just remove the muzzle break and try the same thing again.
With the same load, the gun should blow up "just fine" without the muzzle break.
Pack the barrel as tight as you possibly can with discarded sabots and fire the weapon. I would fire it from the hip I am so sure nothing would happen. Teh problem was bad ammo. probably leftovers from project eldest son.
Brake.
@@skepticalbadger You're right. English isn't my first language, as I am Swedish.
Forgive my misspelling.
Do you know why I can't get out of IKEA it's been 5 years
US Army small arms repairer here. IIRC, it has been many years, sabot rounds arent supposed to be used with a muzzle brake OR flash hider. (yes even the conical flash hider for the M2) because the sabot separates from the round at the end of the rifling. If a muzzle device is attached it can cause the discarded sabot to ricochet off the device and strike the round, causing a deviation in the point of impact. It doesnt happen often, but often enough for the US military to advise against it. A micro deviation at or near the muzzle, can have a huge impact at 1200 meters and beyond. Small dents and dings in a flash hider have very little impact on the weapons operation. A round striking 50- 100 meters outside the impact zone, can have catastrophic results for both the Military, and any civilians or military personnel outside the impact zone. 5 of the 6 branches I know use both the M2 and the Barrett, USA, USMC, USN, USAF, and USCG. I have no information on if the USSF uses either system. The directive on this did not come from any of the branches individually, rather it was a DoD issued directive. Just my humble opinion based on the information I have been exposed to over 28 years in the US Army. I could be wrong.
m.th-cam.com/video/3c4wtfV5_ao/w-d-xo.html
In this video he says it's not the slap engaging with the muzzle. He also hates my idea of chamber vents. I don't see whats wrong with the chamber vent idea.
As another US Army Small Arms Repairer (Since 1995) I agree.
thank you fellow snek
I know they didn't let our sneaky squirrels use them in the barrets. They didn't like us using them in the ma duce that much either. I could be wrong, but it's my opinion that was mostly because those rounds were getting pretty old and they didn't trust them much because of the age. I'm pretty sure we only had once can issued in our entire company, and we got it on a fluke. After the accident I tend to agree. I'm pretty sure that nobody has loaded new SLAP rounds in a very long time.
So, not a safety issue but an accuracy issue. Thanks for clarifying
Hey Mark 🙋it was clear after Scott's test video, that the ammo was significantly overcharged. If gas prices weren't so godawful high I'd put an order in for an RN50 today. Keep being awesome.
For some reason they decide to go on a witch hunt after Mark even though the ammo used during the accident was, as you said, overcharged. A normal .50 round would never be able to shear the steel threads on the rn50. (In my opinion)
@@Noname-yx8gf 100% facts👍
Interesting fact I learned afterwards is that a "undercharged" round can also blow up stuff badly. At first it don't make sense. Once you think about it tho if a round has more powder inside it, less surface area of the grains of powder are exposed to the flash over as it ignites. However if you have less powder it exposes up to like 3× more powder right away as it flashes over and it will cause a higher initial spike of pressure. A casing loaded with more powder has a longer explosion but at a slower rate. If that makes any sense lol. Then a cartridge that has a round pushed down inside it will go off like a stick of dynamite as it will go off nearly at once and have the highest spike I think. Someone who knows this stuff better can weigh in and explain it all better. Neat stuff tho. Unless you're the guy being exploded. Then it kinda cramps your style a bit lol
Just go ahead and give yourself a tracheodomy before testing weird loads made by a stranger and you'll be fine lol
i'd put in an order anyway if they were available in my country. fuck the gas prices, i'd rather walk.
@@hughgrection3052 this is common in nitromethene racing, they literally wash the cylinders with fuel, so much so that the engine is constantly teetering on Hydro lock, even at red line. If you want to hear more, let me know
It’s so cool how much responsibility he takes over this even though it wasn’t really his fault. He wants to make sure this never happens again. To anyone.
I just want to say that seeing the way you reacted to this freak accident & the amount of time dedicated to figuring it out has made me want a Serbu more than ever! RN-50 will likely be the first 50 I get. Products fail at some point, it's impossible to realistically prevent. How the designers of those products react to the failures speaks FAR louder than any durability test in my book
real talk with Mark Serbu. well explained from a passionate gun-maker.
Before the gun blew up, I always thought the design of the RN-50 breech screw plug was just supposed to be a cheap way to make a gun. Never considered the safety.
Then I researched the sheer strength of threads vs lugs. It’s amazing how much more secure threads are than lugs.
So, the RN-50 is probably more safe than the other 50 cal rifles.
Threads are only safer when properly machined and torqued. Threads also don't take very well to wear and repeated cycles as well as lugs do, which is why they're the most common design.
Threads were used on breech loading cannons right up until WW1 and are still used in some modern artillery.
Talishar doesn't seem to be the most informed commenter on this. He has a point about thread wear but as I said interrupted threads are used in some modern artillery to this day.
The RN-50's design has the ears to ensure the minimum amount of thread length engagement. I don't believe the RN-50 uses a tapered thread so... meh
If he really thinks the design is unsafe, I'd love for him to put his money where his mouth is and do the Reliability Analysis. Show me the weibull baby!!
i can only recommend AVE, his tests show how much force is required to overcome threads / the friction of those.
@@Talishar Obviously you haven't heard of the Vulcan V50.
The most succinct, informative, and in my mind definitive review of this KB was done back when it happened on a channel called Backyard Ballistics. Despite the name, the guy is an educated professional firearms examiner tasked with gun crimes & failures. Right off the bat he said that just the threads being sheared showed it was the ammo and not the gun design. He explained several other aspects, like how a failed case will greatly increase bolt thrust, hence his recommendation for gas vents, why low-cycle fatigue is ruled out, and a lot more. Highly recommend anyone interested - you too, Mr. Serbu - check his two vids on the subject.
I'm glad this "rebuttal" has FINALLY come out.
Thank you Mark for putting it in perspective and leveling the field of commentary.
I laud you for your intestinal fortitude and telling the facts regardless of "popularity".
Who was speaking bad about the gun ?
Common sense is a flower that does not grow in everyone's garden.
It's refreshing how confident you are in your engineering and your willingness to tell people they are idiots when they are being idiots. Entirely too many people are overthinking this entire incident and looking to place blame where it doesn't belong. Keep up the great work.
There's nothing common about common sense.
I dig that… I’m gunna use it.
You had my 👍🏻 at the first sentence.
I'm glad that Mark (although jokingly) called out Edwin about his Oxygen Bottle in a Safe antics........ that was super stupid. Sarkissian should know better than that.
And at 200K PSI, a case vent would just turn into a plasma cutting torch
Be like a 40K plasma gun. Saves itself by killing the user.
@@SilverStarHeggisist a smart user throws it like a hand grenade.
@@SilverStarHeggisist Maybe the RN-50's machine spirit was upset that Scott didn't use the proper incense and anointing oils before he fired it.
@@phalanx3803 yes, and that does help eliminate hostiles. There's a minor problem, the angry binary noises coming from the local techpriest at such a ancient and revered weapon being so mistreated.
@@SilverStarHeggisist not my fault they have a habit of overloading and it still purges heretics so the Emperor is happy.
2,000 rounds through my BFG50 and I couldn’t be happier with the platform. Mines in .510 DTC so the ammo is all handmade by myself and therefor far from perfect which should expose any weapon short coming quicker than more consistent ammo production processes.
Thanks for what you do for our community Mark!
Why did you decide to go with the 510 dtc?
From my engineering armchair: you don’t need to make it stronger you need to make it weaker. You want the RN50 to fail in a way that would send shrapnel down range. Add flutes to the receiver to make it weaker then the bolt cap - that would be failing safe. What you described as fail safe was a design that would never fail.
Keep up the good work
Ps I don’t believe this was RN50’s design is at fault but every design can be improved.
At 190 KPSI, there is no "failing safe".
It's simply "How much fragmentation do you want in your grenade?"
awful idea. That sounds like a great way to turn an action into a hand grenade because you're purposely giving it weak points to break apart at. The gun as built can handle proof rounds all day so it's plenty safe for the designed operating parameters plus a safety factor. Buy trustworthy ammo or load your own if you know what the hell you're doing.
Exactly. Fail safe means that when it fails, it fails in a safe way. It does not mean that it never fails. IMO, the problem with the RN50 is not the threaded breach plug, but the two support lugs behind the breach cap. In both explosions on KB's videos, the support lugs became lethal fragmentation.
@@mckennaConfig The lugs probably slowed the cap down enough so it didn't just go through his skull. If I remember correctly, it hit the lugs then went up and hit his safety glasses, which also probably spread out some of the impact, and it still broke his eye socket in a "glancing" blow. Being hit by it straight on would more than likely killed him.
@@argonzeit correct.
Weak threads? Anyone ever look at hydraulic cylinders? Its all held together by fine threads that hold back all that pressure for hundreds of thousands of cycles. 100% wasn't the fault of the threads, definitely an over charged round or and war relic sabotage round with C4 in it that happened to find its way into that batch of ammo. I'd definitely recommend weighing each round of ammo looking for discrepancies when buying old ammo or from anyone really when talking about .50BMG.
Good idea hadn't thought of that.
Yeah man they are stupid as fuk
.. and the threads on the gun are thick and.coarse
Some artillery pieces use an interrupted thread to secure the breach plug. There is absolutely nothing wrong with a threaded plug or cap with adequate sized threads and proper contact. Given that Scott from KY Ballistics did another test and ran seriously overpressure rounds through an RN50 without failure, I'd say the RN50 is just fine. It took making what was effectively a little pipe bomb to break the gun.
@@RustandRedemption The engine in your car does the same thing with a spark plug. An engine at 3000RPM is spinning 50 times a second and in a 4-cycle engine, that means 25 explosions per second per cylinder that your spark plug not only contains, but ignites as well, thus placing itself at ground zero for the combustion event. Absolutely nothing wrong with threaded plugs or caps.
People tend to underestimate bolts and nuts, tension rating wise.
Usually by a factor of 5 to 10.
We colloquially use "failsafe" to mean cannot fail, but that's not what "failsafe" actually means. It means that when something fails, it fails in a safe way. Usually in the form of an intentional weak point. I'm not sure how a failsafe could be designed for this problem. As you point out, simple case vents aren't going to do much.
Any failsafe would be better than none (like the RN-50)
@@muwuny How about telling us which firearms are designed to fail safe?
@@muwuny Did you watch the video?
Did you listen to the words that the man said?
Did you understand what the words the man said meant, or not-even-close?
Because ^The Evidence^ here would suggest at least 2 "No"s in answer to my questions, but hey, you keep-on trying to talk to the grown-ups if it makes you feel clever Buddy... 😉👍
@@muwuny you know what the weakest point in a firearm HAS to be? An unobstructed barrel. Any other weak point and explosive pressure will find it. Maybe not on the first round, or the first 500, but eventually that "fail safe" will fail when it doesn't need to and cause issue. Pressure will follow the path of least resistance, so if that less resistance is anywhere other than pushing a projectile down a barrel, then you don't have a firearm.
@@muwuny You're dealing with pressures at 300% of the pressure rating of a .50 bmg cartridge; More than 180,000 PSI.
There's no way to make that fail safe, anything releasing that much pressure in any direction other than away from you is going to end badly, usually very.
That energy is going somewhere, and if it's gotten to the point where the equipment starts failing, it's usually everywhere.
When you're dealing with extreme equipment, safety is usually managed at the individual level, not the equipment level, for the simple reason that, under extreme circumstances, you just can't get something to fail safely.
Precautions need to be taken, safety needs to be considered at every step along the way, and both of those need to take priority over anything else.
Simple fact of the matter is that Scott got a bad reload.
A very, very bad reload.
There's no accounting for rounds that operate at near 400% of conventional cartridge pressure, that's like taking a hair dryer and hooking it up to high voltage lines.
And when failsafes aren't really an option, the only thing we can do as a community is learn to take precautions, to consider safety more.
Because in the end, Scott fucked up. He didn't _know,_ he couldn't have... But there's lessons to be learnt in every accident, and i don't think the lesson to be learnt here is one that we can simply push off to engineering, and wish them best of luck with it.
This one's one we can all learn from.
And for the record, _no rifle in existence has a 4x operating pressure failsafe, quit the vindictive bullshit._
I'm glad you are talking about this Mark, I've loved your weapons from afar as a poor Canadian. I have nothing but trust in your commercialized designs and wish I could buy them. One day, I'll own your BFG, and your RN50, but again, thank you for talking about how your RN50 works and what went wrong. Especially for giving Scott another one to blow up.
We saw Scott shoot multiple SLAP rounds from the RN-50, and no issues.
One super hot round was all it took, he even went back and remotely fired the rest of those bullets with NO ISSUE.
Keep up the great work, Mark, that's a helluva weapon you've made.
the people pointing out the "weaknesses" of the screw cap clearly have never seen how artillery or naval guns work... those breach blocks are literally threaded, well partially since they're typically a 90° lock which means there's LESS material thread wise in contact between the block and the barrel.
Yeah in the military we had way worse examples that didnt fail. Now I have never fired a RN50 but I would trust its screw cap, because I trusted things like chicago fittings for high pressure liquids and gasses. You hit the nail on the head with this one.
Barrel in an artillery gun will break before the lock, also 90 degree straight lug is safer than threaded ones...
@@Uryendel yea there's a bit more meat to them but you also have quite a bit of surface area with thread engagement which is what gives threaded caps their strength. i know it's not the best of comparisons but there's some similarities in function.
@@ToeCutter454 It's not just there more meat to them, they're designed to fail in a safe way. The RN-50 would be fine if they made sure that the cap was stronger than the barrel (either by having a stronger cap/locking mechanism or a weaker barrel)
@@Uryendel That's an interesting idea, but if the barrel blows up on a rifle like this it's still gonna do very similar damage to the shooter, I wouldn't call it "safer" by any means
I had been looking at buying an RN-50 from my LGS for a while. I bought mine AFTER Scott's blew up. Why? Because of YOUR immediate and calm response AND because of what I saw in the damaged breech end. The fracturing pattern in the threads showed clear excessive pressure.
You build great guns. I love my RN-50. Thanks again for refuting the garbage others have put out about Scott's accident.
It was very clear from his response to the accident that he's the sort of guy you can trust. He was very concerned with finding out the cause and address it if there was a design flaw or manufacturing issue. The problem didn't turn out to be on his end, but it was obvious he was focused on finding out.
I would prefer a bolt-action or automatic .50, but seeing those threads hold themselves from a dozen mystery cartridges embossing their headstamp into the breech plug, that makes me confident enough to a box of proof loads with the thing without breaking a sweat.
Your intelligence on this matter is so much more powerful than internet troll opinions, just know, any person who is interested in this topic and knows anything about it, is comforted by your expertise. I would not hesitate for a second to buy a firearm from you. Bravo big guy
I hope to own a serbu rifle one day, the passion and practical knowledge you have is rare. I have worked with engineers like yourself and I learned so much in a couple years time frame. Good work!
Admittedly, I was one of those suspecting a design flaw when KB blew himself up. For me, it felt logical that when a gun fails, the mass between explosion and the user should be as big as possible and some obstructions (like enclosures) would reduce the force of shrapnel in case something goes wrong. It´s logical that the "ears" that were sheared off were the almost lethal parts that punctured scott. Thus, I found the comparison experiment with the M2 really good as it showed that this really doesn´t change things for the better, but adds other random factors to the issue.
But that´s all besides the point. The gun blew up because the ammo was tampered/faulty and any gun would have blown up. As soon as the gun blows up, it´s rolling the dice if shrapnel goes your way and where it hits you. The "ear" could have missed or it could have punctured the skull.
Well said.
Basically spend an extra 8k for a freak failure to be a bit safer…
If can avoid the problem shouldn’t need the extra safety I suppose. Cost vs benefit.
@@carsonhunt4642 reminds me of ww2 german tank overengineering, i mean the designs were good and all ¿ but did they really need to add so much complexity and extra features when it would work just fine with much less? i really like their tanks and i can easily see they made a massive amount of bad decisions. Tho those bad decisions are one of the biggest reasons why i like learning about engineering in wars
10+ years in the industry…seeing an owner respond like this is porn. Truly amazing to see you come out and set things straight with facts. I need to buy your stuff now 👍🏻
Dont let em get to you Mark. Just keep doing what you do best.
You are an inspiration. Ive
always wanted to have my own firearms manufacturing business and you make me feel like it is obtainable.
Keep up the good work.
I absolutely love that you are willing to stand up for your product. Kuddos
It is pretty obvious from Scott's recent video finishing the last of the ammo box that an improperly loaded round was the cause. I recently blew a 7.2 ounce muzzle brake off a gun with experimental sabot ammo. It simply sheared off the thread adapter and went downrange into the woods somewhere. Recoil was normal with no damage to the receiver and no appreciable case head expansion or case pressure signs. It actually took a few seconds to realize what the downrange noise in the woods was and that the muzzle brake was missing. We can usually tell a lot from examination of what remains. Scott's experience was clearly an over pressurein the chamber event.
I argued the strength of the rn50 for several days after the incident... a whole bunch of people saying "I'd never buy one of these pipe bombs" and then I broke down the numbers for them & pointed out the fact that they would've never put down a deposit on a RN50 to begin with, so that just leaves more for the rest of us... 🤷♂️
Thank you for doing all you do, Mark.
@@rsh4599 that pressure max is so crazy to think about. If anything u would think that ppl would know it is a good rifle becuz it took over x3 the pressure to blow it up. I bet none of my firearms could take 3 times the pressure.
Ahhh Mark... I admire your courage trying to educate people that can't or just won't comprehend things, and who still think they know better about something you have mastered over the years. Seeing your struggle to explain things simply, I can only wish you luck for the future, and hope that you know there's still some sensible and more educated minds who know (to an extent at least) that what you're doing is far from a walk in the park and require a lot of work. Best regards !
I don't know anything about guns. I just follow where the algorithm takes me.
I was initially in the sabot vs break camp, but I was in a gun store and had an epiphany. I was staring at a pre-WWII Reminton Auto-5 with a Cutts compensator. Shotcups are a lot like a sabot. Even if you were a royal fudd like my grandfather, who used a fiber wad and no cup for black powder skeet loads (sorry ghost of Gramp George, no, no, no, oh hell no), then you're really making it worse by shot column vs comp. We've been putting comps on shotguns for a century. If this was a problem, we wouldn't have noticed earlier. The only answer left is ammo, and bleed off holes for a 50 are going to be closer to a cutting torch than anything.
A break will never make a gun explode unless there's some reason the barrel has been completely obstructed lol, pretty sure that KB would have noticed this and whoever came up with the idea is an idiot
How can the sabot make the gun blow up? By the time the sabot gets to the muzzle the pressure already has collapsed.
@@DickCheneyXX the argument was the sabot plastic clogged up the muzzle brake. problem is if that was true the muzzle brake would blow off not explode at the chamber
@@toomanyaccounts also, serbu provided the barrel and brake, specifically for these rounds
@@iceman5117 also the claim that slap shouldn't be fired through a brake appears to be nothing but Fudd lore. the guy knows the President of Barrett so if Barrett ever said anything he would know it.
it takes a number of slaps to go through vehicle armor and hence a machine gun is far better for that then a ten round semi auto material rifle.
I'm actually convinced that the cartridge which injured Scott was *in excess* of 200000psi, because even the rigged cartridge meant to obliterate the rifle in his test couldn't do nearly the same damage.
Looking at the test rifle also championing through the rest of those SLAP cartridges before that actually inspired a lot of confidence in me of the screw plug breech, because you've got those _crazy high_ pressures with most of the cartridges seizing up the breech something fierce, extraction was a project almost every time, and still the gun didn't blow or even so much as burst or bulge the barrel.
I'll be frank and say that the RN-50 isn't a dream gun for me, but I'm also convinced it's an extremely safe rifle, few other guns on the market would tolerate the nonsense conditions it could go through here. I mean, will people call an antique Colt 1873 a death trap because you can Elmer Keith the thing with smokeless handloads? I wouldn't, and those guns aren't even drop-safe.
I think in many ways it's an awkward rifle, if money wasn't an issue I think it would be an odd choice, but agree that it appears to be very rugged/overbuilt
My guess would have been pistol powder or something, if not purposely made to be over-pressure
@@Wehra96 There's a lot of different things which could have been wrong with it. The powder could have degraded from bad storage conditions _(and according to some, these SLAP cartridges used a different powder from normal .50BMG ball which was less shelf stable, however true that claim is),_ along with it potentially being a counterfeit made with something like pistol powder, which itself could have degraded.
Some suggest that it was a salted round, like Project Eldest Son, but I find that be less likely. Being a Cold War spy project thing, and such a specific one at that, it seems to me that it would be odd for it to pertain to a .50 BMG SLAP of all things, something which never got around anywhere with any enemies of the US or NATO, and then that cartridge would have to make its way back and onto the US.
I really think that it's either a counterfeit which wasn't expected to be shot, or that it was a genuine SLAP but which had its powder charge degrade one way or another, the odds are just far higher.
Why doesn't it use interrupted threads? That would have been way more convenient
@@tedarcher9120 using ears as safety check to ensure breach is closed would not work if you had essentially a quick change interrupted thread breach cap. Or you’d need to much more tightly tolerance the space between rear of cap and ears, which could interfere with the closing of the gun. A workaround I could see is an indexing detent on the cap that would only allow the gun to fire if the cap is rotated to the proper location, but then we are talking a more complex safety mechanism than just making it so the action won’t close until you have adequate closure of the breech cap.
Very inspiring to see honest gun designers, I'm glad you responded with such integrity.
Thanks I always learn something new from you!
I still feel that the rounds that were used were overloaded and dangerous. Too many people love to use heresy and innuendo without actual proof or facts, especially on the internet. You know what you're doing Mark and you stepped up from the beginning. I'd buy one o your 50's................ If I had the money, lol. Seriously, thanks for all of the videos you've put out and for addressing everything. Stay safe.
As non-native English language user:
I always thought that "safe" and "failsafe" are 2 quite distinctively different words. "Safe" doesn't fail, "failsafe" fails but in the most safe way possible.
Maybe I am wrong, maybe I'm making a mistake of translating English term back into my language and then searching for its meaning.
Something being "failsafe" means it's highly unlikely to fail
But HAVING A FAILSAFE means having some sort of backup for when it does fail.
I fully understand how this is confusing
Yeah, a failsafe device or feature is designed such that a failure results in what is most likely to be the safest state available considering the failure.
So, for instance, at least one set of brakes on large commercial trucks and on railroad trains are designed to apply if air pressure is lost, rather than being unable to apply the brakes. Obviously, there will be situations where this isn't ideal(a single drum losing its air supply and overheating and starting a fire, for instance), but it is almost always better than the alternative of all the weight rolling freely.
Another example is a lot of nuclear reactors will drop their control rods in place in the event of a power failure or if the control system detects issues with the coolant system, thereby slowing the reaction to a crawl and greatly reducing the risk of a meltdown. While there are probably a few situations where this would be less than ideal, I'm struggling to think of any atm.
@@1stCallipostle The OPs interpretation is correct - something that is *designed* to "fail-safe" is precisely that; WHEN it fails (failure is always an option), it *should* fail in a safe way.
But reality doesn't always agree with your design.
Something that is safe cannot cause harm; if it can, then it's not safe, *but* we do often use "safe" to mean "very low risk". (E.g. "safe driver" - driving is inherently dangerous.)
@@spudgamer6049 and that's more or less what the ears are for on the RN-50. He designed it to take like 150 percent of rated pressure and the amount of force to SHEAR those off is incredible. The powder obviously burned far too quickly so he had a small explosive in the chamber.... ouch.,
@@ExarchGaming I disagree. When/if the design fails, it fails in a fairly bad way. It just is designed not to fail except under extreme circumstances. That's different than being designed to fail in a safe-ish way.
Not saying there's anything necessarily wrong with the design. You can only realistically design for what is within the reasonable realm after all, and I'm not sure that there are any particularly good ways to make a 50bmg chambered gun fail in a relatively safe manner that doesn't compromise it in other ways. Maybe those ears could be made strong enough such that something else would give before them, but I'm not sure how heavy that would make the gun, or even if that is realistically possible.
I had doubts about the gun at first but after seeing so many gun influencers showing the capability of this rifle. I fully back this rifle. For those rounds that KB shot I did some research and found out that even when those rounds where being manufactured, they where still a bit dodgy during production. They took years to perfect the round and they knew the exact specs required to make that round reliable. After finding out that he purchased those rounds online I just thought “someone who probably just knows the basics of the .50 BMG rounds. Not much in the lane for the specialty SLAP rounds.” The gun still has my full support. I can see it in my safe down the line from now. And I look forward to it! Great gun love your videos. Keep spreading the knowledge
Exquisitely eloquently stated. I haven't heard such a perfectly preformed take down of ones detractors in quite a while.
Said with passion and love for what you do and explained everything in such an easy to digest format.
It was very organic and well said.
I look forward to watching more.
It's funny Mark mentioned being less safe by trying to be more safe. The 1st Generation Dodge Viper is kind of an example of that. Back in the late 80s, there was no traction control system or stability control system. The driver's right foot was the traction control system. The driver's hands on the wheel was the stability control. The 1st Gen Viper had very wide tires for the day (and they're still wide today) in order to give it lots of grip for that monster of a motor it was carrying. And it worked! The Viper had a ton of grip, but it was also kind of a problem. You see, you could use all that power and get going really fast indeed, but it also meant that once you crossed the limits of traction, you were going really freaking fast when it did let go and chances are that most drivers didn't have the skill to bring the car back in line. Issac Newton was in the drivers seat at that point and you hoped that Chrysler's engineers built a safe car, because you f***ed around and were about to find out.
The viper is still one of my favorite cars ever. And great analogy. Those big tires are so sexy though 😍
having spent several years driving an early viper I can tell ya that when you finally exceeded the grip / handling limits - there was lots of flailing arms, swearing and sweating and the eventual change of underwear and stiff drink hahaha , that car forced you to concentrate 110% of the time when driving it, even if just popping to the shops...
But it was such fun and a very rewarding car to drive, even if my ears didn't agree with my choice of straight thru side exit pipes >_
That car had no safety features 😂😂
@@6FStyleCo seat belts and good luck.
i dont know if i couldve thought of a worse metaphor. the first gen dodge viper was a death trap
Scott from Kentucky Ballistics did a test with 3 rounds, the first with a normal powder charge, the second with a 1.5 times powder charge and the third with a heavy double powder charge. It was the third round with the heavy double powder charge that blew up in almost exactly the same manner as the first RN-50 that almost ended him. Scott followed up with a second test with a new RN-50 and a new round with a heavy double charge. Again the results were almost identical to the first one that blew up on him and the first test rifle. None of the rounds he used for the tests were Sabot rounds to eliminate that as a factor. His conclusion was that he used rounds which he could not verify were factory loads. His new policy now is to only buy rounds from sources that he knows and trusts.
It wasn't the gun that was faulty, it was in fact bad ammunition.
Well said. It's like putting a 400 shot of nitrous into a 4 cylinder grocery getter. Even if you can get it to not extinguish the plugs, it's not going to last very long.
this doesnt change that the RN50 has unsafe points of failure, the cap is its main weakness and any failure in the cap will result in it being tossed at the shooter as shrapnel, an easy way to fix that would be to design the chamber walls such that they were still strong, but weaker than the cap, so that any round loaded normally still fires normal, but dangerous overpressure would rupture the chamber walls, venting pressure to the sides, where, on a safe range, noone should be standing
@@gaiamission7200 if you can thing of a way to make a gun explode in a safe direction, let me know.
@@evoxis1058 it's extremely doable and common on reputable manufacturers. Also he totally just explained it but ok
@@gaiamission7200 did you miss the part where scott also blew up a barret 50 and it did exactly the same thing?
Mark has been a Patriot and 2nd amendment advocate for decades. Guy is stand up dude.
The RN-50 is an amazing weapon and a great price to get into a 50cal. I’m not scared at all!!Something that finally failed at 400% capacity is about the best advertisement you could get for a firearm.
The amount of people who don't understand that a bolt action is just interrupted threading is astounding. And that complete threads are going to be stronger.
Mechanically there's a huge difference between machine threads and bolt lugs
I didnt know anything about that and i also dont have any thread knowlege. That being said, without any knowlege of that stuff, i always though a bolt action was safer compared to that breach cap just by the look of it. Its like judging a book by its cover, its ok to do it but don't go around spreading potentially miss information about the subject to anyone.
@@Pilot8091 how so?
Depends on coarseness and depth of threads. Yes artillery is interrupted thread breach but very coarse and deep. A bolt on bolt action even one with 9 lugs is not interrupted thread it is similar but not interrupted thread. And much stronger than medium to fine solid threads.
@@Pilot8091 yes, of course. They both distribute the pressure (force) across more surface area.
Mark, you've earned my respect just from the work you've been doing on this. If I weren't a poor, I'd have no problem buying one of your products.
That was very well covered and your diagnosis i thought was excellent, you know and know how to build a safe 50 cal!
Brother I had only heard of your brand with no experience with it. But after all the videos I've seen be it forgotten weapons, or even Kentucky ballistics themselves I want a Serbu 50 about as much as I want anything in this world. It's affordable already but after all the tests I've seen they have to be one of the best made period. Mr. Mark you make a great product but most importantly from all I've seen you're a good man and wish you nothing but continued luck and success.
As a machinist and someone who has worked on all types of metals for all sorts of things, I know for a fact that cap is no joke. I also know whatever can blow it off is no joke too lol.. Lot of guys here and on KB's comments who obviously have never worked on any metal in their life trying to act like they know everything about threads, metallurgy, pressure loads.. I'd ignore it. Like you said, too many people here just want to be heard and want to pretend they're better than someone else for personal brownie points
Absolutely right. There’s no way in hell the sabot would get stuck enough to blow up the gun under normal pressure. People who believe that are probably thinking about guns in movies, or those old-time shotgun barrels made from fused sheet metal. Modern, proper firearms made from quality materials are really brutally hard to create a barrel obstruction severe enough to blow up the gun with. Threading the inside of the barrel and screwing in a 2-inch bolt can do it, but less than that is unlikely to make any difference.
I’d shoot the RN-50, no qualms. As long as the ammunition is verified as standard-issue and within tolerance of the weapon.
It’s definitely written in military manuals and other manufacturers 50cal. Manuals for a reason. They usually don’t just scribble in “beliefs” in those things.
@@brianjames8600 Be specific. Exactly what do they write; “Don’t use sabot rounds with a muzzle break” or “Using sabot rounds with a muzzle break can obstruct the barrel enough to blow up the whole gun”? Because there’s a difference in intent and breadth of consequences. Do you have these manuals and instructions handy to quote them word for word? If you can, please do, as it would be interesting to see the way they formulate it.
Man I can't imagine having a company and dealing with an issue like this. With how people are so willing to internalize their first instinct and then dismiss anything that could challenge that thought, really fighting an uphill battle even if you are completely in the right.
I am not dismissing new evedence, but I don't think the owner of the company should be labeling potential costomers as stupid for asking more detailed questions.
That's where you can seperate the good from the bad gun channels, the good ones immediately went to the ammo as the cause.
One thing that I've wondered since then: if the threads had held for that round, what was the next failure point?
Imagine if it was fragments of the firing pin assembly, heading straight back through the shooter's torso?
The way the guns assembled wouldn't the firing pin have to come out through the back of the cap, though?
@@mustangmckraken1150
Yes. Cap stays and pin blows right through it.
Imagine if that cap had as many threads on it as a modern inline muzzle loader...
@@wilsonrawlin8547 It's also possible that, with enough pressure, he could have simply split the barrel back by the action. Which would have had a nearly identical effect.
@@PhotonHerald
Indeed. Just a massively overcharged round/explosion.
Scott himself said that it wasn't the fault of the gun. The really hot, overcharged ammo (presumably tampered) was absolutely at fault. Threads like that do not fail unless you seriously overpressurize the chamber.
He just got super unlucky.
Anyone claiming that something got stuck in the muzzle brake is wrong and clearly hasn't watched Scott's follow up video when he re-tried the test. He went through all 12 SLAP rounds and it didn't blow up. It took a round that he specifically massively overcharged before it actually blew up the gun.
counterfeit rounds are known to exist. it takes five bucks of material to make a counterfeit slap that would go for a 100 bucks at a gun show
Scott should have blamed himself more
@@toomanyaccounts correct, they're all kinds of counterfeit slap rounds and the way to identify them is they do not have a crimp, their primers are usually brass colored and not nickel colored like real ones, fake ones usually do not have the primer sealant present like the real ones do, and on the Sabot, fake ones do not have the little cuts on the top to aid in splitting apart to release the projectile.
"if anyone wants to disagree with this, comment below so we can make fun of how stupid you are" is the best thing I've heard all day
The fact that people think a little bit of plastic would stop a force that also sends a 700 grain metal projectile 3000 fps.....
Yess we been waiting for this, thanks dude ❤️
Oh you are welcome sir!
I have faith in your engineering. That's why I ordered one and I'm willing to wait the 18 month lead time. Keep up the great work!
I will be 100% honest boss. I immediately wanted your rifle because of the Kentucky Ballistic accident. In his recreation video, I was floored at the amount of abuse that rifle took. Such a great design!
In a video from not too long ago, Gun Jesus discussed that any firearm design has to be a compromise between firepower, weight, cost, and durability, and a few other things. Many of these factors are directly opposed to one another. Weight and durability are a great example: If durability is your main goal you are going to have to compromise on weight, and visa versa. The take away is that there is no one gun design that can do everything "best", it's always a balance of compromises.
Mark, for what it's worth from a stranger on the internet, I think you've handled this incident really well. You have been transparent and communicative, not hiding behind PR and legalese. Scott from KB seemed more than happy with how you worked with him, and that's the most important thing to me.
Bmw had a fail safe that made frontal collisions basically impossible, but my wife still crashed it
Women do the damnedest of things sometimes.....
There's a Navy expression "sailor-proof," generally followed by the conclusion that nothing is. A sailor can always find a way to break it.
@@reliantncc1864 What's the saying about Marines? Put them in a room that has no doors or windows with a steel sphere for 24 hours and they will have broken the sphere, lost it, or impregnated it? Something like that. (Not hating on Marines, just a joke.) Doesn't matter how "safe" something is made, some idiot will find a way to unsafe it.
The genius physicist/ metallurgist/engineer ,Matt at CRS firearms , jumped on the "unsafe" design band wagon and even showed in his "expert" what you should have done.
I unfollowed him after those comments . Was very happy to hear he issued an apology and conceded that he was incorrect.
@@cberge8 The rarest trait on the internet is saying I was wrong, I'm sorry.
@@SilverStarHeggisist Almost unheard of, especially online.
Never listen to boys in a rainbow hat with a spinner on top. Or sideways baseball cap. Same thing.
@@cberge8
I also unfollowed that douche nozzle because I can't stand people who know absolutely nothing about a particular subject , except for a Google search ,then give"expert" advice on that subject. It would be like giving a brain surgeon tips , because you watched a film in biology class about the brain.
Matt's apology was a hollow gesture and CYA. He used his platform to trash a Guy and his product , that he knew ABSOLUTELY NOTHING,about
then say ,oops my bad ,sorry.
Very informative discussion. I am a Mechanical Engineer who enjoys all your videos. I never was scared of the RN-50. I am still awaiting the full release sale of the AOW RN-20 Mike Mike (20 mm Vulcan Rounds with explosive primer's. I believe the 20mm rounds can take 50 BMG primers. I bought some 20mm rounds from a well-known reloader but wound-up reselling them with the 1 ea. 20mm Vulcan barrel. The hard-to-find part to make a cannon is the breech. It is very difficult for just some guy to put together a 20mm cannon. Barrels typically come with interrupted threads which typically fits nothing anybody has laying around for that rainy weekend project
Thank you for being one of the most rational voice in the gun world. It"s needed, a lot.
I will reiterate:
My opinion, as an experienced, trained engineer that also shoots... Is that Mark's design is solid.
Accidents happen, and I believe the ammunition caused this one. I don't see where suing Serbu is beneficial to our hobby.
I think that the gun may have been i micro bit weaker than the new one since he shot it before but it would be neglible. So all the fault was on the slap rounds.
Sry for bad english im a swede.
It’s obvious it’s the ammo but the gun design fails catastrophically for the user. No other 50 on the market would fail so dangerously given that same round
@@OrloTheM3D1C 0:20 wrong. That could definitely kill someone.
@@OrloTheM3D1C yea but you cant fix that cause its breach.
Thank you Mark! Thank you for all you do for the community.
Hi Mark (metallurgical engineer here). All of these analysis videos are excellent, keep it up! One detail I would like to correct you on, though. Yes, the stress-strain curve will change shape with different grades/heat treating of the steel ears, and making them bigger will increase the magnitude of the curve on the stress axis. But making the ears "stronger" (strength generally means the peak stress value on the curve) does not make them move faster when they shear off. The burning propellant converts a finite kinetic energy to the cap when the threads finally let go, and the area underneath that stress strain curve represents the amount of that kinetic energy dissipated by deforming the steel. The more energy dissipated by deformation, the less energy available to accelerate the ears AFTER they shear off. Next up, we gotta talk about how Time-Temperature-Transformation curves set the rules for what you can heat treat with that induction heater...
I’m a mechanical engineer though I always gravitated towards thermo rather than materials. I can definitely imagine a situation though where the deformation isn’t plastic in most of the ear instead storing energy due to a bending force and when the ear breaks off that energy is released, snapping the ear flat against whatever broke it off thus shooting the ears off faster than they might’ve otherwise gone. Like those poppers you’d play with as a kid, turning them inside out and waiting for them to pop out. Would that be an unreasonable analysis if the ears had defined areas of acute stress where they snapped and the rest of the ear experienced it’s own bending force?
Edit: also worth mentioning that the cap doesn’t stop being pushed/acted on by the explosion until after its already launched those ears to kingdom come
Having watched many of RNS' videos, including his .50BMG gun design, I'm just glad Mark stepped in and helped him design a better much safer gun.
I have always doubted the "plastic sabot stuck in the muzzle brake" theory... Plastic just simply cannot hold that kind of pressure without giving way.. I have seen copper bullets of the entirely wrong caliber get swaged through a rifle bore without any damage to the receiver or bolt... I still think those s.l.a.p. rounds were loaded with too fast of a rifle powder.. Or a pistol powder... Pistol powder in a rifle will cause big problems!! But that's just my thoughts on that situation...
Love ya Mark! Keep em coming!☺👍🇺🇸
Pistol powder in a rifle is great for cast bullets. But it's also way too easy to overcharge a case with the tiny amounts of powder that are used, so you have to really be paying attention while you're loading. It's possible the same kind of thing happened here - they used a regular rifle powder when a slow-burning magnum rifle powder was needed, and ended up doing a double or triple charge.
Yep! Same here.
Mark your a good man for deep diving into Scott's accident! IMO I believe almost everyone believes that the round it's self was incompetently and egregiously overcharged with powder I believe that you provide a phenomenal product and that the accident had nothing to do with said product but you are good man for your diligence sir!
I think Scott proved that pretty conclusively when he (the madman!) fired the rest of those rounds in a much later video. Those were definitely spiked rounds.
Hr proved it by using the rest of his rounds and it only blew, when he put in a hot round.
Vindicated!
I’ll admit I was in the sabot vs muzzle break camp before your reply videos. Your analysis was thorough and knowledgeable. Mea culpa.
Mark, I’m an engineer and you are living through my second worst nightmare (I’m sure you can guess the first). I’ve followed this since Scott’s video went up, with multiple perspectives.
I want you to know, you did good work. You produced a safe product, given every reasonable situation. Scott’s videos show how over-hot those SLAPS were loaded at, and the one that exploded was WAY over pressure. I wish Scott had saved the rest for a powder analysis but we can’t live in the past.
You are a good designer, and the fact that this upsets you shows that you are a good man.
Thanks Mark for keeping everyone in the loop,I own one of your RN50 before the KB accident was shot before and since,being a heavy equipment mechanic I truly believe in threads,bad accident,bad round,gun not at fault.
I appreciate the on going breakdowns and addressing the accident. I respect the time and effort that you put into this.
Mark is awesome and transparent; this is why after I receive my first RN-50 I will order more. If Mark is confident and has the receipts to back it, I will trust him with my life and others.
Still standing with you Mark. No fear.
Just throwing this out there for some food for thought Mark and curious watchers. When I was in combat in Iraq we got tasked to actually implement spiked ammo into the battlefield ( enemy ammo calibers of course). It's a highly effective way to have passive attacks on the enemy, break up enemy moral, break up enemy supply trust, etc... As far as I know our RIFLE ammo never was spiked enough to kill but meant to destroy the weapon first, and have slight secondary injuries just as a bonus. Most times just a destroyed AK, RPK and some scratches and cuts on the hands and face/ eyes. We did have lethal stuff too but that was for mortar and artillery shells that got used for making IED's. Those weapons were tracked and could be detonated on command (very interesting tactics can be implemented with these babies). When you start talking bigger caliber rifles and machine guns like DShK's and NATO .50's there really is no safe way to destroy those weapons without making them highly likely to kill the user. It just is what it is...Make no mistakes about it though, the enemy was doing the same thing to our ammo. Hardly ever happened to americans because we hardly used battlefield pick up weapons and ammo. It's very easy to use this tactic on guerilla elements because they use what they can get most times... Saying that, there is alot of people that re sell weapons and ammo from conflict zones where these tactics are being used. Unless you are apart of the team that spiked or left the ammo on the battlefield theres not a great way to inspect and know which ammo is spiked and which is normal ammo... I would recommend never buying boutique ammo off of sites like Ebay.
I call BS on your whole story. This is the first time I've heard of the US doing this since Vietnam. And who in their right mind thinks you can buy ammo from eBay?
@@njw1977 lol whatever you say buddy. Not here to convince you of anything. Quit being lazy
@@njw1977 Let me know what local gunshop is carrying legit .50 SLAP rounds when you get a chance.
You're stupid if you think you can buy ammo on eBay.
Mark,you are spot on. I am an army vet,and ive been diggin n talkin to chums and no warnings exist that we can find. Keep on keepin on! Merica!!
Mark, I deeply respect you for your handling of the absolute tsunami of opinion people have thrown at you regarding your design. The design of your gun is not what made the KB incident happen. And you are completely correct when you said, "There is no such thing as a fail-safe." Anything can be made to blow up if enough explosives are put in it. That bullet that blew KB's gun apart would have decimated most guns it was shot out of - regardless of their design.
I thought the consensus was that the slap round had improper powder, and it caused an over pressure in the chamber. First time on your channel sir, kudos for the analysis. Keep building amazing arms!!
"Fail-safe" does _not_ mean "cannot fail" -- it means that _when_ it fails, the failure mode will be SAFE (rather than dangerous). One well-known example is the "crowbar circuit" which creates a short circuit to force a fuse to blow in order to prevent catastrophic damage to the power supply when a failure occurs.
I don’t think he meant that it means “cannot fail” but rather that for extreme cases there’s no way to guarantee it fail safely.
some people seem to use fail-safe without considering its meaning, they may mean the chance of a failure or unsafe condition is exceedingly unlikely
another good example, glider training operations. the braided kevlar tow rope always had two weak links made of poly rope, if a strong thermal comes, truck is too fast or the pilot is climbing too much, or somehow the glider cant pop its release. weak link pops and prevents airframe, tow vehicle, or expensive haul rope damage, and just becomes a small pain in the ass for the pilot to modify his flight, and for me chasing the rope through the swamp.
When there is too much pressure, it is simply impossible. Everything can become a pipe bomb if enough pressure is accumulated fast enough.
Exactly!
To Mark: As an engineers we want REDUNDANCY in safety measures, that is what "fail safe" means. Measures that are destructively tested to prove they work as fail safes (aka redundancies). Personally you should probably listen to "gun jesus". He just might have some knowledge you lack.
Screw caps are barely considered adequate on sub-guns, much less 50 cal bolt-action rifles.
And the whole "heat treat it, yeah..." comment.... for F's sake hire a materials engineer and/or metallurgist if you make a 50 cal Bolt action. Don't tell us "heat treat it yeah..."
And larger, more-secure "bigger things" (i.e. safety mechanisms) "flying off" would "fly off" exponentially slower... and would not "cut your head off". No ones "trolling" this man, but he sure loves to blame the internet when his gun blows up.
@Hornet135
Of course it can never be 100% safe. But it will significantly improve safety by a magnitude. Look at crash tests on cars. Imagine if they gave up in 1930 and just said "fuck it, car crashes occur with too many variable let's just give up on making cars safer."
Instead they made fail-safes called crumple zones, which Ian says is similar to the arisaka vent holes and safety cap which are made to redirect energy away from the user. With enough energy of course these safeties will still hurt the user. But now you need a hell of a lot more energy to hurt them.
Mark, Indeed it was bad what happened to Scott. Love both of your channels. When I watched Scott's video of the Rn-50 blowing up on him. Not once did I say the gun was at fault.
Myself, I am not an engineer, Yet I am a mechanic that hunts and reloads. Lot of experience with things that goes boom and blowing up stuff also. The very first thing I thought of was, That round was over charged by or with the wrong powder. Or it being old, the chemical change with time made the powder a lot more volatile than normal. Also, for the record, I do have a place set aside in my gun safe for an RN- 50. Just do not have the land yet to fire one.
Folks are something else. K.B. showed and explained it was the ammo. , Then the ES video with the barrel embedded in concrete showed the craftsmanship of the firearm. Keep up the great work. Awesome video. Don't stress the trolls
Just some fun things to think about:
Gunpowder is not supposed to explode under normal use. It is meant to burn really fast, but not so fast that it counts as an explosion. It may all seem instantaneous to us, but there is a big difference between how fast pressure rises when gunpowder burns versus explodes. So, designing for handling an over-charged cartridge is not the same as containing an explosion, and no gun manufacturer plans for their gun to have an explosion in the breech.
Large caliber revolvers are some of the more common recipients of ‘oops, wrong powder’ explosions that I know of. You average revolver has all the gas venting you could possibly want with the cylinder gap, and the clearance behind the cylinder. It’s about as ventilated as a chamber can get. They still can’t vent enough pressure to keep from blowing apart when enough fast-burning powder is in the cartridge to cause an explosion. I’m general, the chamber will split in half lengthwise and get launched into the top strap hard enough to bend or snap it. This tends not to be deadly as most shrapnel goes upward, but it does fuck up peoples hands pretty bad sometimes. The ears on the RN-50 are already much stronger than the part of a revolver frame that would keep the cylinder from blowing back into your face, so I don’t think making the ears stronger would be very helpful. If anything, the chamber on the RN-50 is too strong. If you put a relief cut on the side of the chamber so that, if the action does fail, we know it will blow out of that area, like we know a revolver is going to crack the cylinder in half and launch it up into the air, maybe that could help?
Nothing is going to keep a gun from turning into a bomb if there is an explosion in the chamber. The best you can do is try to make it blow up in as predictable a way as possible. So, if there is a problem, it isn’t that the gun isn’t strong enough. It is that it is so strong we don’t know exactly how it is going to fail when someone puts a bomb in the chamber!