The first 2 times you made the repairing Edwin's gun with expoded parts joke I kinda chuckled but the third time it was 10x funnier to me. I genuinely love your sense of humor. Thanks for making these videos to entertain us for free practically. You seem like a good dude.
The way It tore up the bullet, messed it up for long enough for it to get 9" down the barrel before the bullet expanded to plug the bore. and then split the chamber and barrel to shreds. Thanks Mark!
The grain structure of the barrel? It looks like the grain structure of a piece of wood. The shockwave is supersonic, but more importantly it is supersonic in Steel. The speed of sound for a pressure wave traveling forward(compression) in steel is approximately 18000 ft/s, but the speed of sound for an S wave(a shearing wave) is only 10,000ft/s. C4 generates a shockwave of roughly 12000-15000 ft/s according to Google, this is faster than the steel can flex in a shear direction. So, the steel hasnt been ripped apart from tensile strength, it was pulled apart by shear strength. As the C4 detonates, the molecules have no issue staying rigid in a outward or radial direction from the explosion, but the metal is no longer solid in an axial or tangential direction around the barrel. The molecules can hang on to the other molecules on top of or below them, but they are being accelerated too fast to keep attached to the molecules beside them. It would seem obvious that the pressure is simply pushing everything outwards from the center, but the fact that the shockwave is traveling faster than steel can transmit motion literally splits it apart at a molecular level.
@@ricksanchez9669 it's actually a thing. it's called an ETC Cannon, and has been explored recently for use in tank guns. and yes, i want to see a big collab to make and fire a C4-powered cannon. get kentucky balastics, mark, inrange TV, and ordnance lab in the same video! maybe even get cody's lab or a few of the science/simulation channels in on it.
Fascinating. Richard Marcinko wrote of finding VC camps or ammo caches and carefully pulling bullets and reloading just a few of their 7.72x39 rounds with C4, so they’d never know when an AK might blow up in their face.
I'm not sure that he was advocating cleaning with a steel rod. (He was knocking a bullet out of the barrel, not cleaning it.) Also, I'm not sure that the barrel crown is all that important to the accuracy of this particular firearm anymore.
Your supposed to start with the minimum charge of C4 and work up in .5grain increments. He went straight for a max load. Classic rookie 50BMG reloading mistake.
I think it would make a great light fixture now hanging from the ceiling. Cut the barrel short, wire a light into the blown out part, you've got yourself a whole new product line. 👍👍👍👍👍👍🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸
The texture is more than likely an artifact of the granular structure of the steel. When under very high pressure, it will start to rip apart at the lines of the crystalline structure of the metal. I saw much of the same in Iraq with damaged vehicles, IED shrapnel, and mortar frag.
The texture of the chamber looks a lot like adiabatic sheer bands. Essentially when the material is being deformed rapidly it generates heat. That heat softens the material which makes it weaker which then makes it more likely to deform at the same spot. Positive feedback loop and you have tearing around a few areas rather than plastic deformation across a larger area. Of course in slower deformations the heat has time to dissipate which is why you don't see this. It isn't just in explosive mind. Its more common in plastics because they are less conductive whilst also losing strength more quickly by heat. There you can get adiabatic sheering through impact and other more conventional means. You can in metals too, but it just takes a far more dynamic situation. Solid cannon projectile impacts for example.
Your comparison of the chamber/barrel parts looking like wood seems to be a good analogy, it resembles a broken branch from an old growth hardwood tree. Very informative, thank you.
Just something I noticed on the ears that didn't tare off in this experiment I saw that you have blind holse near the front corner one large and a second smaller what are there use and can they be moved further from the front face or removed entirely because it looks as tho they are causing a higher stress concentration on the front corner. would love to hear any feedback and thankyou for the video
The shear lines from the barrel splitting, the fractured ends from where metal was almost pulled apart from itself, and the compression fractures all show why PSI is an important measurement to take into account.
Looks like the neck of the brass was separated from the body and was traveling with the bullet! Not 100 percent sure though the colors on it looks like mangled brass. Did anyone else see it or could tell?
The case base squeezing between those threads like that? It MUST have been super-critical. Let that sink in, this isn't he damage from pressures that can turn brass into a super-critical state. My mind is blown that the damage was so miniscule! And man, like I said last time, that grain structure in the barrel is ART!
Love the analysis series! The Fact that you’re looking into this, and Scott is doing his own testing says a lot of you. Thank you Mark for your diligence and awesome service! One day I hope to be able to afford a Serbu… but today, I’m just a broke Military Vet stuck in CommieFornia
@@hotrodcharliegreen I’m trying man! I literally just retired on Saturday, and was not only born here… I Enlisted so I could get out… “Uncle Sam” sent me back after 16 years of service!
This is a horrible drinking game. Don't think I can get through the video without alcohol poisoning. Neat to see this analysis. Thanks for so openly testing your product to destruction.
Very interesting (as usual) but this one made you think a bit clearer regarding loads forces and compression energy . Astonishing result . Thanks for the upload especially seeing your own work blasted to hell and learning from it and proving a point . Jonny UK
You are right about the brass plating. Putting force alot of force in it on it is called explosion welding and yes that's actually a thing.😉 Would love to see some high resolution images of the steel.
The granular nature of the little solid chunks of the comp-4 that was used cause an uneven propagation of shockwave that can (and usually does) create texture on malleable surfaces in metals.
The plastic deformation of the fire control group housing is impressive, to say the least. I've seen some shit happen with receiver failures in the past where other people's guns exploded for one reason or another (probably another case of Bubba's pissin' hot reloads, like it was with Scott, just in smaller calibers), but nothing quite that uniquely severe (usually shit just blows out the side of the lower or upper and you gotta replace one/both). I'm really glad you're doing all this for everybody Mark, I know it isn't cheap blowing up so many guns for science, but somebody's gotta do it right? Wouldn't be right otherwise, and you don't seem like the type of guy to let something go unaddressed. At least this one you were able to do from sub-standard parts that weren't going to be sold, but which were mechanically identical to ones going into production guns, for all intents and purposes
The texture looks very much like stretch marks. Considering the amount of pressure on the steel and the very fast time, it is not far fetched to think the steel was starting to tear just as skin does when it is stretched too quickly. The sides of my knee caps look just like that chamber piece.
My SWAG on the texture is the metal grain being expanded and split apart, with the force making more progress in areas where the grains give, which then bunches up the stiffer areas as they get surrounded. It's probably not exactly analogous but it reminds me of looking at how the universe started. You have this inflationary period that starts as this smooth and homogeneous state of high energy; but super subtle and once microscopic variations in densities as things expanded so rapidly, become massive long filaments of density that form over time into the galaxies, attracting material away from the voids in between. So I wouldn't be surprised if some fundamental physics concept could be linked to both scenarios.
Texture's there because the metal stretched, it's drawn (or blown) down into weaker sections of crystal structure. Some parts may be gas cut as well, which is also what happened to the base of that projectile. If you're handier with the math and material strength calculations than me (not difficult), you could get a lot of data from how long the transition areas are in the splits on that barrel, because pretty much all of it from the brass 'dusted' area on forwards was torn purely by the inertia from the directly affected parts that still remained attached.
wow, incredible, the brass was molecularily bonded to the steel, the steel looks brittle and layered like mica... the speed that a solid can turn into a gas is wicked, basically at 26.5K feet per second or 17.8K mph hell, thats nearly the same speed the ISS is moving thru space in its orbit... you need a "faster" camera, something in the range of 500K FPS to be able to catch the action in detail...
This reaffirms my original thought that Scotts round was a reload that someone replaced the original volume of powder with pistol powder, or overfilled with pistol powder. The pressure spike from the speed of the propellent. That millisecond it took to burn the full case of that SLAP put the pressure on the threads, supported by the barrel/bullet/throat/case/chamber/cap. The C4 going so much faster, the pressure spike only took place in the chamber because there was no time. To me this shows the threads in the cap are as hard as you say they are.
Could it be, that: the explosion sends the bullet down the barrel and at the same time makes the barrel expand - and because the bullet has a "head start" from being located in front of the explosion, it gets those 8-9 inches into the barrel, before the barrel deformation squeezes it in. I expect the mushrooming of the barrel to make the inner radius slightly smaller, at the end where each "branch" is still attached. Fascinating pictures!
A couple of things are involved. High pressure is one thing. But the speed of the explosion of C-4 is very fast. So the bullet didn’t have time to travel very far down the barrel until the pressure peaked and overcame the action. That’s one reason why they like ANFO for blowing rocks in populated areas. The velocity is much slower than nitro and doesn’t cause so much damage to other homes.
@1:15 I am assuming the high explosives caused the steel to fail intragranularly. That patterern looks awful similar to the elongated grains of the rolling direction of the steel. Grains of rolled steel such as your chamber are long and blocky.
7:00 Side plates look like the ears took a little deformation from the cap before the zippering chamber walls shoved them aside. Should be contact marks visible.
My guess is that the heat and pressure was enough to move the surface of the steel off of the solid section of the phase chart, the liquid part flowed a bit and as fast as it liquified, the pressure subsided and the steel re-solidified. From what I know about fractures, the rifling created stress risers which is why it split kind of symmetrically but the smooth portions shouldn't have deformed so much because the crack propagation is like the safety valve for over pressure. Any way, whatever happened happened fast and it doesn't seem like that area got hot enough to accelerate corrosion which is why I think it was mostly pressure that melted it.
I love the "brass plating", you can really see where the brass "leaked" out when the barrel burst open. It kinda reminds me of chiral crystals from Death Stranding 😁
This experiment ended how I suspected. What was unexpected is the bullet had enough energy to make it a few inches and that’s it. The pressure spike was so fast the whole breech must have been opened up before the bullet even moved. That’s wild😮
@@CandidZulu No, it was the C4 that made things worse, it's a high explosive, unlike gun powder. When the high explosion happens, it doesn't matter if the barrel has a bullet in it, or don't.
Thats definitely explosive deformation. Steel looks like that after you pop a C4 cutting charge. It goes so fast that it shears. That area of the breach was where the case head of the round was, the pressure spiked the highest there.
Making it thicker would not make it work: the metal nearest the explosive would be wrecked even if the outer diameter stayed intact. The forces are too much for any material to stand, even ceramics.
When you find out, you're still only going to be able to get a single shot out of it. If you can contain that much pressure, the creation of that pressure will produce enough heat to send a lot of the steel out the barrel as vapor.
Everyone asking about how to actually launch a projectile with C4 started the gears turning... asides from being milled into a foundry block of steel, you'd need a really thick "cartridge" designed to be ablative rather than obturating... sealing is out of the question, so the focus goes to having enough of a calorie-absorbing material to avoid eroding everything, which probably also means having the projectile in the base of an a soft metal tube cast or pressed into probably a UHDPE 'case' that's a few inches thick completely surrounding a little nugget of primary explosive, cone shaped towards the front so it aligns the freebore with the start of the rifling. What plastic is left after firing is probably going to be a molten glob, and parts of the tube are probably going to chase the projectile down the barrel (may have to have a 'tamper' of PE behind that too, keep it from gas cutting). Tube could be perhaps zinc? The heat in the chamber would be plenty to vaporize it and ease cleanup a little. Oh well, bored minds go strange places. Kind of like wondering if you could drive a projectile with an 'open chamber' and a shaped charge, design the projectile like a bullet trap grenade launching system, gets hit with the copper slug and catches it to transfer all it's kinetic energy to itself and give it a full send.
Brother basically what you made is a mini shape charge inside of the barrel. the barrel actually contained the explosion enough to wear the copper when it expanded cut the barrel and embedded the remaining copper Metals in the steel.
Something I've come to notice over the years is the amount of relative force produced by different methods and the effects on materials. Steam and black powder are classed as low explosives and if you want to simply break something, they work fine. When you get to nitrocellulose, a little bit seems to be a power of magnitude greater and it's effect is to break things down a bit finer. Nitroglycerin will crack things open like nobody's business and the chunks are smaller yet. TNT, as we all know will break down mountains into gravel and C-4 will tear metal apart into little bits. I'd like to see a 4k ultra slow video of that barrel disintegrating so I could follow all the material as it departed. I am willing to bet that a lot of it was used to create steel dust.
I think the bullet got stuck in the barrel, not just because the pressure dropped when the gun disintegrated, but also because while the pressure was so high, the steel core would have expanded sideways like a lead bullet in an early black-powder rifle. Even in some of the early breechloaders, the lead bullet was just bore-sized, and relied on the the explosion of the black powder behind it to make it expand to fit the rifling. Elmer Keith used to use the term "upsettage rounds" for cartridges (such as the Sharps) which were intended to do this. The bullet base did not need to be hollow like a Minnie ball to work, especially if it was long and heavy and made out of relatively soft lead. I suspect the bullet in this case had expanded so much coming out of the cartridge that it was helping to split the barrel apart as it travelled along it.
Anyone else admiring how the brass basically became its own self contained brazing process and surrounded the bullet? I’m trying to figure out if the plastified brass basically sealed the barrel by filling in the gaps in the rifling until there was enough there to make the barrel yield or how that happened..? I think it almost had to be in a plastic state because if it was vapor or completely molten it would have shot past the projectile. We all know copper is a great heat conductor but going from molten to almost solid in the small contact band seems like an enormous amount of heat dissipation in a really short time. The rupture happened so fast it makes me wonder if a similar thing would happen without the projectile or did the projectile play a part in the destruction?
This is something I saw many, many years ago and want to know more about. Had a client who bent metal using explosives, or I think explosive forming was the more technical term. Process worked a bit like vacuum forming or blowing a plate into a form, only with a lot more blow. Apparently one of the other applications was to coat or laminate metals. So sheet of copper over another metal, sheet of explosive over that, one later and the materials are bonded. It was one of those 'well, huh!' moments, but being a semi-retired engineer, something I've wondered about since. I suspect there's a lot of material knowledge required given the stresses involved.
@@brolohalflemming7042 Explosives welding is a thing; when done correctly, it forms these lovely little ripples, like "waves" when viewed in cross-section of the two. It allows for the conjoining of two dissimilar metals for which conventional welding would otherwise be impossible. The artist Evelyn Rosenberg is probably the first acknowledged "detonographer," one who created metal sculpture embossed, formed, or otherwise created using explosives. It's possible, for example, to inscribe a leaf with remarkable detail by placing it between a sheet each of metal and Detasheet. There's a bit of cleaning, polishing, and flattening after that, understandably, but the detail is remarkable. Her book is Detonography: The Explosive Art of Evelyn Rosenberg. Some of her work is on display in Socorro, NM. As for the curious details found in Mr. Serbu's experiment, perhaps I'm just not seeing it clearly enough but it seems that the sharp explosive deformation resulted in the steel forming cracks in the same way that hitting a non-Newtonian fluid sharply enough will cause rupture instead of plastic deformation.
@@ericyoung7049 Thank you for the reply, and I'll have to look into Rosenberg's work. Somehow, I very much doubt the UK authorities would grant me an explosives licence for art projects though. But it's fascinating the way advances in both high speed photography and materials science have advanced engineering. Now, scientists can video lasers in slow motion.
@@brolohalflemming7042 My understanding is that Evelyn does all the set-up, design, etc., and simply directs how the explosives are to be laid out. In this fashion, she has no concerns about the bunker for storage, nor any issues with handling, purchasing, transporting, etc. Not a bad idea, if someone else can carry all that extra water for you, I suppose.
That weird striated texture on the metal is extremely similar to the shell fragments I've found where they used artillery in the past to clear avalanches.
Love these vids, The steel fragments en barrel pieces look like artillery round shrapnel after they blow, sorry arty man here 🙂Looks like the force stretched the steel until it could no longer hold on forming all these layer like lines.
the explosive impulse probobly deformed the barrel and theads into the cap, so before the threads ripped off completely they hit like 110% engagement and that's why there are some left. the cap HAD to split to disengage them the rest of the way, and where ever it cracked, it got launched the opposite way The texture is the actual grain structure. you can tell the heat treatment did a really good job, because that almost wood like texture is from the crystalline structure being stretched. you can see the same thing if you acid etch wrought iron. Actually, i'd be curious to that a little piece of this acid etched to really bring out the detail in that grain
Way cool I wonder the amount of c4 it would take to put the projectile down range outstanding video awesome content thank you for sharing five stars brother
I wonder if the intense heat and impact from the C-4 being that confined caused the metal of the chamber to retemper or crystalize? Resulting in the stress fracturing seen there? Great video.
The brass is probably explosively welded to the steel On the subject of the patterning, it is probably from the manufacturing of the barrels. If it has significant forging your get broad alignment of the crystal grains and when it breaks it can reveal that pattern
that would make one hell of a wall hanger, attach everything in an 'exploded view' on a panel and display it as such, probably tack weld the bits onto a minimal supporting frame just to hold everything in rough positioning
That surface cracking looks just like the "alligator skin" you see just forward of the chamber in well-used barrels from lots of exposure to hot, pressurized gasses over time... perhaps it's just an effect of the super-heating of the explosion along with the high pressures causing the metal crystal structure to break down. As the son of an engineer (and a chemist myself, but not specialized in metals), I'd recommend you check out the metallurgy studies behind the alligator cracking on worn out barrel throats and that will probably tell you what happened on those chamber surface sections.
Unfortunately I've seen the aftermath of what things look like after a 240-pound chunk of HMX detonated in front of two people in a fortified building (it was an accident). The amount of pressure and flash heat is incredible. There was nothing left of the two men, nor most of the building, however there was an eerie reverse-imprint on one wall with embossed outlines of where the two were standing when it went high-order. Chemically and physically speaking, C4 is half as explosive as that pressed HMX shape charge was. To put it into further perspective how spooky explosive it is, it's the same compound used to compress highly dense plutonium and uranium to start nuclear fission in warheads. Steel and concrete have no chance unless you have several feet thick of it.
Destructive Fractures and micro-fractures from the explosive pressure exceeding the strength and elasticity of the steel . Guess you didn't find the Cap yet ? Thanks Mark !
Re the bullet. The reason it got stuck where it did is due to the base of the bullet being forced forwards before the bullet overcomes it's inertia effectively forming a plug. The chamber was in the process of rupturing anyway so the plugged barrel was incidental to the failure not the cause.
Not an explosives or metallurgical nerd, but I can throw a presumption into why the formerly smooth chamber walls now have texture. I think it has a fair bit to do with the steel grain alignment in the forging or drawing process. After that the grain lines were cut by a drill then a reamer but not eliminated. They were still there, only concealed and would have remained so until a high enough pressure shock load compressed the 'weaker' spaces between the harder grain lines. It's one of those little detaily things that can be seen in a piece of draw forged, hammer forged vs cast. If the piece is heated up o cherry red and really de-scaled if you look close you can see darker and slightly lighter lines in the metal. Faint lines that look almost like a shattered pane of glass is indicating a forged billet that isn't refined. If the lady nes are uniform, it's been hammer forged. If the lines are long and skinny, draw forged. They are hard to see no doubt, but they are there. Knife makers know about grain size and the need to have them uniform and directional. Still neato to see.
So now the question is, what would it take to use high explosive as a propellant in a gun? 3'×3' block of steel, muzzle loaded with a tungsten carbide projectile?
The first 2 times you made the repairing Edwin's gun with expoded parts joke I kinda chuckled but the third time it was 10x funnier to me. I genuinely love your sense of humor. Thanks for making these videos to entertain us for free practically. You seem like a good dude.
I didn't catch that the first time. I remember him saying it about the locking block.
Supersonic strain rate failure along grain boundaries creates that look.
I've seen that same "brass plating" in case head failures.
The flowered barrell is a beautiful example of brisance.
It's shredded the steel in an amazing way
The way It tore up the bullet, messed it up for long enough for it to get 9" down the barrel before the bullet expanded to plug the bore. and then split the chamber and barrel to shreds. Thanks Mark!
The grain structure of the barrel? It looks like the grain structure of a piece of wood.
The shockwave is supersonic, but more importantly it is supersonic in Steel. The speed of sound for a pressure wave traveling forward(compression) in steel is approximately 18000 ft/s, but the speed of sound for an S wave(a shearing wave) is only 10,000ft/s. C4 generates a shockwave of roughly 12000-15000 ft/s according to Google, this is faster than the steel can flex in a shear direction. So, the steel hasnt been ripped apart from tensile strength, it was pulled apart by shear strength.
As the C4 detonates, the molecules have no issue staying rigid in a outward or radial direction from the explosion, but the metal is no longer solid in an axial or tangential direction around the barrel. The molecules can hang on to the other molecules on top of or below them, but they are being accelerated too fast to keep attached to the molecules beside them.
It would seem obvious that the pressure is simply pushing everything outwards from the center, but the fact that the shockwave is traveling faster than steel can transmit motion literally splits it apart at a molecular level.
Now , I am waiting for Matt from CRS to explain how you could've designed safety features to prevent that from happening 🤣🤣🤣
Imagine a tank cannon bored at 50 cal...
He would do that huh ? 😂😂😂
@@bunnykiller i would actually like to see this done. Would the bullet even survive? Maybe Kentucky can get it done.
@@ricksanchez9669 it's actually a thing. it's called an ETC Cannon, and has been explored recently for use in tank guns.
and yes, i want to see a big collab to make and fire a C4-powered cannon. get kentucky balastics, mark, inrange TV, and ordnance lab in the same video! maybe even get cody's lab or a few of the science/simulation channels in on it.
@@osarkthegoat7038 holy shit a useful TH-cam comment? Mark this day! Thank you good sir! I have a Google rabbit hole to attend to
I'm going to steal a word from Inspector gadget after seeing that barrel, "WOWZERS!!"
Mark seems to be a great guy. A guy that chases truth and knowledge. I would not hesitate to buy a gun from this man.
Do it then.
True machinist.
Fascinating. Richard Marcinko wrote of finding VC camps or ammo caches and carefully pulling bullets and reloading just a few of their 7.72x39 rounds with C4, so they’d never know when an AK might blow up in their face.
What makes you a great gunsmith is your inquisitive mind. Keep up the great work Mark!
Never use a steel cleaning rod and never clean from the muzzle. YOU'RE GONNA WRECK THE CROWN ON THAT BARREL. Thought a gunsmith would know that 😏
I'm not sure that he was advocating cleaning with a steel rod. (He was knocking a bullet out of the barrel, not cleaning it.)
Also, I'm not sure that the barrel crown is all that important to the accuracy of this particular firearm anymore.
Your supposed to start with the minimum charge of C4 and work up in .5grain increments. He went straight for a max load. Classic rookie 50BMG reloading mistake.
You think that really matters on a barrel that’s been destroyed.
I'm thinking some of you might have missed the joke...
@@VagabondTexan Im thinking alot of them missed the smiley face at the end of the statement
I think it would make a great light fixture now hanging from the ceiling. Cut the barrel short, wire a light into the blown out part, you've got yourself a whole new product line. 👍👍👍👍👍👍🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸
The texture is more than likely an artifact of the granular structure of the steel. When under very high pressure, it will start to rip apart at the lines of the crystalline structure of the metal. I saw much of the same in Iraq with damaged vehicles, IED shrapnel, and mortar frag.
I was going to comment on the crystalline structure of the steel as well.
The energy dump there was amazing!
The texture of the chamber looks a lot like adiabatic sheer bands. Essentially when the material is being deformed rapidly it generates heat. That heat softens the material which makes it weaker which then makes it more likely to deform at the same spot. Positive feedback loop and you have tearing around a few areas rather than plastic deformation across a larger area. Of course in slower deformations the heat has time to dissipate which is why you don't see this.
It isn't just in explosive mind. Its more common in plastics because they are less conductive whilst also losing strength more quickly by heat. There you can get adiabatic sheering through impact and other more conventional means. You can in metals too, but it just takes a far more dynamic situation. Solid cannon projectile impacts for example.
Your comparison of the chamber/barrel parts looking like wood seems to be a good analogy, it resembles a broken branch from an old growth hardwood tree. Very informative, thank you.
Mark was right, Ian only put a dent in Tampa. I was in fort myers and that place and nearby cities were leveled.
Just something I noticed on the ears that didn't tare off in this experiment I saw that you have blind holse near the front corner one large and a second smaller what are there use and can they be moved further from the front face or removed entirely because it looks as tho they are causing a higher stress concentration on the front corner. would love to hear any feedback and thankyou for the video
love this channel. one day i'll make it on to the waiting list for a RN-50
Get on the list now, start selling blood, you will have the money by the time comes to pay the final payment..
The shear lines from the barrel splitting, the fractured ends from where metal was almost pulled apart from itself, and the compression fractures all show why PSI is an important measurement to take into account.
Very interesting Mark, really liked this one. Can't beleive how much brass was spread around through that rifle. Thank you for showing this.
Looks like the neck of the brass was separated from the body and was traveling with the bullet! Not 100 percent sure though the colors on it looks like mangled brass.
Did anyone else see it or could tell?
The blast seems to have liquidfied the brass and tried to push it out in front of the bullet via the rifling
The case base squeezing between those threads like that? It MUST have been super-critical. Let that sink in, this isn't he damage from pressures that can turn brass into a super-critical state. My mind is blown that the damage was so miniscule! And man, like I said last time, that grain structure in the barrel is ART!
Love the analysis series! The Fact that you’re looking into this, and Scott is doing his own testing says a lot of you. Thank you Mark for your diligence and awesome service!
One day I hope to be able to afford a Serbu… but today, I’m just a broke Military Vet stuck in CommieFornia
GET OUT of the Peoples democratic republic of californistan....
@@hotrodcharliegreen I’m trying man! I literally just retired on Saturday, and was not only born here… I Enlisted so I could get out… “Uncle Sam” sent me back after 16 years of service!
@@hotrodcharliegreen Florida, South Carolina, or North Carolina are what I consider “Home”
I wonder if there was a small enough amount of C4 in the round whether you COULD use it to trigger safely?
I also want to see this.
That was indeed neat and interesting 😁💥 Thanks for taking time to do the demonstration
NEW DRINKING GAME!
....shut up liver, you're fine
This is a horrible drinking game. Don't think I can get through the video without alcohol poisoning.
Neat to see this analysis. Thanks for so openly testing your product to destruction.
Looks like Elmer and Bugs bunny situation..lol
I was literally gonna say it looks like something out of a cartoon lmao😂
👍
More like Elmer Keith.
I'm so excited to finally receive my RN. 2 years and change. Planning on my first 50 Saturday morning
That first piece is actual art, that is a wallhanger for SURE!
Very interesting (as usual) but this one made you think a bit clearer regarding loads forces and compression energy . Astonishing result . Thanks for the upload especially seeing your own work blasted to hell and learning from it and proving a point . Jonny UK
You are right about the brass plating.
Putting force alot of force in it on it is called explosion welding and yes that's actually a thing.😉
Would love to see some high resolution images of the steel.
The granular nature of the little solid chunks of the comp-4 that was used cause an uneven propagation of shockwave that can (and usually does) create texture on malleable surfaces in metals.
The plastic deformation of the fire control group housing is impressive, to say the least. I've seen some shit happen with receiver failures in the past where other people's guns exploded for one reason or another (probably another case of Bubba's pissin' hot reloads, like it was with Scott, just in smaller calibers), but nothing quite that uniquely severe (usually shit just blows out the side of the lower or upper and you gotta replace one/both). I'm really glad you're doing all this for everybody Mark, I know it isn't cheap blowing up so many guns for science, but somebody's gotta do it right? Wouldn't be right otherwise, and you don't seem like the type of guy to let something go unaddressed. At least this one you were able to do from sub-standard parts that weren't going to be sold, but which were mechanically identical to ones going into production guns, for all intents and purposes
It looks like the striations in genuine old wrought iron.
The texture looks very much like stretch marks. Considering the amount of pressure on the steel and the very fast time, it is not far fetched to think the steel was starting to tear just as skin does when it is stretched too quickly. The sides of my knee caps look just like that chamber piece.
Similar principles 🤷🏾♂️
Note to self, do not reload with C4 😂😂 Awesome video Mark!
You should put a liner in this barrel and make a .22 with the banana peeled chamber as the muzzle end.
That would be pretty cool.
My SWAG on the texture is the metal grain being expanded and split apart, with the force making more progress in areas where the grains give, which then bunches up the stiffer areas as they get surrounded.
It's probably not exactly analogous but it reminds me of looking at how the universe started. You have this inflationary period that starts as this smooth and homogeneous state of high energy; but super subtle and once microscopic variations in densities as things expanded so rapidly, become massive long filaments of density that form over time into the galaxies, attracting material away from the voids in between. So I wouldn't be surprised if some fundamental physics concept could be linked to both scenarios.
Might try getting in touch with ordinance lab they do a lot of explosives I mean a lot
I was about to ask why you did this but then I watched the other video again. Wicked cool footage.
Texture's there because the metal stretched, it's drawn (or blown) down into weaker sections of crystal structure. Some parts may be gas cut as well, which is also what happened to the base of that projectile. If you're handier with the math and material strength calculations than me (not difficult), you could get a lot of data from how long the transition areas are in the splits on that barrel, because pretty much all of it from the brass 'dusted' area on forwards was torn purely by the inertia from the directly affected parts that still remained attached.
Putting this in one of Edwin’s guns; hahahaha ; that’s funny Mark! Such a cool experiment on this! RIP RN-50!
Great follow up! I was waiting for this.
wow, incredible, the brass was molecularily bonded to the steel, the steel looks brittle and layered like mica... the speed that a solid can turn into a gas is wicked, basically at 26.5K feet per second or 17.8K mph hell, thats nearly the same speed the ISS is moving thru space in its orbit... you need a "faster" camera, something in the range of 500K FPS to be able to catch the action in detail...
Call up the Slow-Mo Guys and have them come out to the range with their Phantoms 👻
Pretty cool where the breech blew up how you can see what looks like the crystalline grain of the steel that has been shattered.
This reaffirms my original thought that Scotts round was a reload that someone replaced the original volume of powder with pistol powder, or overfilled with pistol powder. The pressure spike from the speed of the propellent. That millisecond it took to burn the full case of that SLAP put the pressure on the threads, supported by the barrel/bullet/throat/case/chamber/cap. The C4 going so much faster, the pressure spike only took place in the chamber because there was no time. To me this shows the threads in the cap are as hard as you say they are.
Mark has thrown down the gauntlet Kentucky Ballistics. This is how a real professional blows up a gun! 😂
Could it be, that: the explosion sends the bullet down the barrel and at the same time makes the barrel expand - and because the bullet has a "head start" from being located in front of the explosion, it gets those 8-9 inches into the barrel, before the barrel deformation squeezes it in. I expect the mushrooming of the barrel to make the inner radius slightly smaller, at the end where each "branch" is still attached.
Fascinating pictures!
A couple of things are involved. High pressure is one thing. But the speed of the explosion of C-4 is very fast. So the bullet didn’t have time to travel very far down the barrel until the pressure peaked and overcame the action. That’s one reason why they like ANFO for blowing rocks in populated areas. The velocity is much slower than nitro and doesn’t cause so much damage to other homes.
@1:15 I am assuming the high explosives caused the steel to fail intragranularly. That patterern looks awful similar to the elongated grains of the rolling direction of the steel. Grains of rolled steel such as your chamber are long and blocky.
7:00 Side plates look like the ears took a little deformation from the cap before the zippering chamber walls shoved them aside. Should be contact marks visible.
Love these videos.
My guess is that the heat and pressure was enough to move the surface of the steel off of the solid section of the phase chart, the liquid part flowed a bit and as fast as it liquified, the pressure subsided and the steel re-solidified.
From what I know about fractures, the rifling created stress risers which is why it split kind of symmetrically but the smooth portions shouldn't have deformed so much because the crack propagation is like the safety valve for over pressure.
Any way, whatever happened happened fast and it doesn't seem like that area got hot enough to accelerate corrosion which is why I think it was mostly pressure that melted it.
That splayed barrel end looks like a piece of art to me.
You should put it on a display stand
I love the "brass plating", you can really see where the brass "leaked" out when the barrel burst open.
It kinda reminds me of chiral crystals from Death Stranding 😁
Looks like modern art! Awesome!
How much did the speed of the explosion play a part in the focused damage in comparison to slower burning gun powder?
Very good video. Would have loved to see the destroyed part next to an original or a complete one. Would give more reference.
What an interesting video to eat brunch to. Thanks Mark
Very cool test and analysis...
Will there be any improvements after studying this?
This experiment ended how I suspected. What was unexpected is the bullet had enough energy to make it a few inches and that’s it. The pressure spike was so fast the whole breech must have been opened up before the bullet even moved. That’s wild😮
Bullet obturated and made things worse I'd bet!?
@@CandidZulu Maybe, but I think with those kind of forces "worse" is purely relative.
@@CandidZulu No, it was the C4 that made things worse, it's a high explosive, unlike gun powder. When the high explosion happens, it doesn't matter if the barrel has a bullet in it, or don't.
Thats definitely explosive deformation. Steel looks like that after you pop a C4 cutting charge. It goes so fast that it shears. That area of the breach was where the case head of the round was, the pressure spiked the highest there.
My hex key set looks just like yours. Love those things.
I wonder how thick the chamber/barrel would actually have to be to contain a C4 cartridge.
Making it thicker would not make it work: the metal nearest the explosive would be wrecked even if the outer diameter stayed intact. The forces are too much for any material to stand, even ceramics.
c4 thunder mug would be neat
Really thick, but the chamber would still deform and ruin the gun.
Stalinium could handled it...
When you find out, you're still only going to be able to get a single shot out of it. If you can contain that much pressure, the creation of that pressure will produce enough heat to send a lot of the steel out the barrel as vapor.
Everyone asking about how to actually launch a projectile with C4 started the gears turning... asides from being milled into a foundry block of steel, you'd need a really thick "cartridge" designed to be ablative rather than obturating... sealing is out of the question, so the focus goes to having enough of a calorie-absorbing material to avoid eroding everything, which probably also means having the projectile in the base of an a soft metal tube cast or pressed into probably a UHDPE 'case' that's a few inches thick completely surrounding a little nugget of primary explosive, cone shaped towards the front so it aligns the freebore with the start of the rifling. What plastic is left after firing is probably going to be a molten glob, and parts of the tube are probably going to chase the projectile down the barrel (may have to have a 'tamper' of PE behind that too, keep it from gas cutting). Tube could be perhaps zinc? The heat in the chamber would be plenty to vaporize it and ease cleanup a little.
Oh well, bored minds go strange places. Kind of like wondering if you could drive a projectile with an 'open chamber' and a shaped charge, design the projectile like a bullet trap grenade launching system, gets hit with the copper slug and catches it to transfer all it's kinetic energy to itself and give it a full send.
The first man to send a breaching cap to the moon!
Brother basically what you made is a mini shape charge inside of the barrel. the barrel actually contained the explosion enough to wear the copper when it expanded cut the barrel and embedded the remaining copper Metals in the steel.
Absolutely fascinating.
Something I've come to notice over the years is the amount of relative force produced by different methods and the effects on materials. Steam and black powder are classed as low explosives and if you want to simply break something, they work fine. When you get to nitrocellulose, a little bit seems to be a power of magnitude greater and it's effect is to break things down a bit finer. Nitroglycerin will crack things open like nobody's business and the chunks are smaller yet. TNT, as we all know will break down mountains into gravel and C-4 will tear metal apart into little bits. I'd like to see a 4k ultra slow video of that barrel disintegrating so I could follow all the material as it departed. I am willing to bet that a lot of it was used to create steel dust.
I think the bullet got stuck in the barrel, not just because the pressure dropped when the gun disintegrated, but also because while the pressure was so high, the steel core would have expanded sideways like a lead bullet in an early black-powder rifle. Even in some of the early breechloaders, the lead bullet was just bore-sized, and relied on the the explosion of the black powder behind it to make it expand to fit the rifling. Elmer Keith used to use the term "upsettage rounds" for cartridges (such as the Sharps) which were intended to do this. The bullet base did not need to be hollow like a Minnie ball to work, especially if it was long and heavy and made out of relatively soft lead. I suspect the bullet in this case had expanded so much coming out of the cartridge that it was helping to split the barrel apart as it travelled along it.
Anyone else admiring how the brass basically became its own self contained brazing process and surrounded the bullet? I’m trying to figure out if the plastified brass basically sealed the barrel by filling in the gaps in the rifling until there was enough there to make the barrel yield or how that happened..?
I think it almost had to be in a plastic state because if it was vapor or completely molten it would have shot past the projectile. We all know copper is a great heat conductor but going from molten to almost solid in the small contact band seems like an enormous amount of heat dissipation in a really short time.
The rupture happened so fast it makes me wonder if a similar thing would happen without the projectile or did the projectile play a part in the destruction?
This is something I saw many, many years ago and want to know more about. Had a client who bent metal using explosives, or I think explosive forming was the more technical term. Process worked a bit like vacuum forming or blowing a plate into a form, only with a lot more blow. Apparently one of the other applications was to coat or laminate metals. So sheet of copper over another metal, sheet of explosive over that, one later and the materials are bonded. It was one of those 'well, huh!' moments, but being a semi-retired engineer, something I've wondered about since. I suspect there's a lot of material knowledge required given the stresses involved.
@@brolohalflemming7042 Explosives welding is a thing; when done correctly, it forms these lovely little ripples, like "waves" when viewed in cross-section of the two. It allows for the conjoining of two dissimilar metals for which conventional welding would otherwise be impossible.
The artist Evelyn Rosenberg is probably the first acknowledged "detonographer," one who created metal sculpture embossed, formed, or otherwise created using explosives. It's possible, for example, to inscribe a leaf with remarkable detail by placing it between a sheet each of metal and Detasheet. There's a bit of cleaning, polishing, and flattening after that, understandably, but the detail is remarkable. Her book is Detonography: The Explosive Art of Evelyn Rosenberg. Some of her work is on display in Socorro, NM.
As for the curious details found in Mr. Serbu's experiment, perhaps I'm just not seeing it clearly enough but it seems that the sharp explosive deformation resulted in the steel forming cracks in the same way that hitting a non-Newtonian fluid sharply enough will cause rupture instead of plastic deformation.
@@ericyoung7049 Thank you for the reply, and I'll have to look into Rosenberg's work. Somehow, I very much doubt the UK authorities would grant me an explosives licence for art projects though. But it's fascinating the way advances in both high speed photography and materials science have advanced engineering. Now, scientists can video lasers in slow motion.
@@brolohalflemming7042 My understanding is that Evelyn does all the set-up, design, etc., and simply directs how the explosives are to be laid out. In this fashion, she has no concerns about the bunker for storage, nor any issues with handling, purchasing, transporting, etc. Not a bad idea, if someone else can carry all that extra water for you, I suppose.
👍 that's pretty impressive... definitely very interesting
That weird striated texture on the metal is extremely similar to the shell fragments I've found where they used artillery in the past to clear avalanches.
"Neh. The bore looks okay..."
ON A SUNFLOWERED BARREL!
That bore is MOST DEFINITELY *NOT* OKAY MARK!
=)
I kid! I kid!
Love these vids, The steel fragments en barrel pieces look like artillery round shrapnel after they blow, sorry arty man here 🙂Looks like the force stretched the steel until it could no longer hold on forming all these layer like lines.
the explosive impulse probobly deformed the barrel and theads into the cap, so before the threads ripped off completely they hit like 110% engagement and that's why there are some left. the cap HAD to split to disengage them the rest of the way, and where ever it cracked, it got launched the opposite way
The texture is the actual grain structure. you can tell the heat treatment did a really good job, because that almost wood like texture is from the crystalline structure being stretched.
you can see the same thing if you acid etch wrought iron.
Actually, i'd be curious to that a little piece of this acid etched to really bring out the detail in that grain
Way cool I wonder the amount of c4 it would take to put the projectile down range outstanding video awesome content thank you for sharing five stars brother
Tell Edwin "it's the age of recycling, man" and make a functional/safe to use rifle with some bent up parts from this. Haha
I wonder if the intense heat and impact from the C-4 being that confined caused the metal of the chamber to retemper or crystalize? Resulting in the stress fracturing seen there? Great video.
The brass is probably explosively welded to the steel
On the subject of the patterning, it is probably from the manufacturing of the barrels. If it has significant forging your get broad alignment of the crystal grains and when it breaks it can reveal that pattern
that would make one hell of a wall hanger, attach everything in an 'exploded view' on a panel and display it as such, probably tack weld the bits onto a minimal supporting frame just to hold everything in rough positioning
Interesting. Interesting. Interesting.
Useful results.
Nuts……so much pressure..
That surface cracking looks just like the "alligator skin" you see just forward of the chamber in well-used barrels from lots of exposure to hot, pressurized gasses over time... perhaps it's just an effect of the super-heating of the explosion along with the high pressures causing the metal crystal structure to break down.
As the son of an engineer (and a chemist myself, but not specialized in metals), I'd recommend you check out the metallurgy studies behind the alligator cracking on worn out barrel throats and that will probably tell you what happened on those chamber surface sections.
Unfortunately I've seen the aftermath of what things look like after a 240-pound chunk of HMX detonated in front of two people in a fortified building (it was an accident). The amount of pressure and flash heat is incredible. There was nothing left of the two men, nor most of the building, however there was an eerie reverse-imprint on one wall with embossed outlines of where the two were standing when it went high-order. Chemically and physically speaking, C4 is half as explosive as that pressed HMX shape charge was. To put it into further perspective how spooky explosive it is, it's the same compound used to compress highly dense plutonium and uranium to start nuclear fission in warheads. Steel and concrete have no chance unless you have several feet thick of it.
Destructive Fractures and micro-fractures from the explosive pressure exceeding the strength and elasticity of the steel . Guess you didn't find the Cap yet ? Thanks Mark !
I wonder if a hammer forged barrel would have gotten textured like that? I'm not sure if it's a product of the steel or the pressure wave.
Steel microstructure/grain?
Drawn tube or forged blank for barrel, overpressure caused cracks along the grains, which give that pattern?
Very interesting to me how that brass cold welded to everything!
Who'd have thought how much fun we'd have at Scott's expense?!
Re the bullet.
The reason it got stuck where it did is due to the base of the bullet being forced forwards before the bullet overcomes it's inertia effectively forming a plug.
The chamber was in the process of rupturing anyway so the plugged barrel was incidental to the failure not the cause.
The only time I stop AK50 videos is to watch The BMG Bomber videos.
I think you found a new plating process for parts!
Not an explosives or metallurgical nerd, but I can throw a presumption into why the formerly smooth chamber walls now have texture. I think it has a fair bit to do with the steel grain alignment in the forging or drawing process. After that the grain lines were cut by a drill then a reamer but not eliminated. They were still there, only concealed and would have remained so until a high enough pressure shock load compressed the 'weaker' spaces between the harder grain lines.
It's one of those little detaily things that can be seen in a piece of draw forged, hammer forged vs cast. If the piece is heated up o cherry red and really de-scaled if you look close you can see darker and slightly lighter lines in the metal. Faint lines that look almost like a shattered pane of glass is indicating a forged billet that isn't refined. If the lady nes are uniform, it's been hammer forged. If the lines are long and skinny, draw forged. They are hard to see no doubt, but they are there. Knife makers know about grain size and the need to have them uniform and directional. Still neato to see.
Awesome video. Love the content
So now the question is, what would it take to use high explosive as a propellant in a gun? 3'×3' block of steel, muzzle loaded with a tungsten carbide projectile?
Isn't that yellow coloring from the c4 ionizing the air and metal? Pretty cool thank you for showing us
Very cool Mark.