How Does It Work: Lever Delayed Blowback
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- เผยแพร่เมื่อ 25 ส.ค. 2024
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Lever-delayed blowback is a relatively uncommon action system, although it is applicable to a wide variety fo firearms and has been successfully used in submachine guns, rifles, and light machine guns. It uses a principle of mechanical disadvantage on a fulcrum lever to force a mass to accelerate rearward while the bolt remains closed. This allows the effective weight of the moving parts to be amplified, resulting in a lighter firearm.
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"...only a relatively small number have ever made it into MAS production..."
I see what you did there ;-)
Went to see this. Not disappointed ^^
Well, the FAMAS is a FAMouS example.
No bueno, need MAS produced.
@@DivingHawker Oh ! Le jeu de mot laid...(le jeu de mollets !)
in french we call this system "inertia amplification" (in AA52 and FAMAS)
No, you call it amplification d'inertie.
That is a more accurate name
Zorg Enterprises!
@@smorrow In German it is "electrical tension".
I was hoping to see TKB-517 that Ian found in Narnia... I'll get over it, the FAMAS is pretty cool.
Lmao also that M43 it's pretty rare
InRange shoots a match and features another bullpup in several videos
Ian: "I must find a reason to make a video with the Famas..."
Great video! Really loving the "How Does It Work" series. Its nice to get a good clear and simple explanation about how different firearms technologies work.
Cheers!
One of the coolest systems, simplicity is a beautiful thing
Another cool aspect of this mechanism is that the charging handle, being connected do the bolt carrier, acts from the "advantaged" side of the system, which actually makes racking the bolt easier (or at least not more difficult, depending on the circumstances).
True.
once again, another highly informative video. I really can't say it enough, but thank you.
" How can I show my FAMAS without showing my FAMAS? " 🤔
*making video about lever delayed action*
When I think I know something about guns and then watch an episode of forgotten weapons.
I know nothing
I think of the "roller delayed blow back" and "toggle look" being the same thing. In practice inte a degrecive spring. Am suprised that its concidered to be so different from eachother. Just different mecanical solutions to acheve the same result. Though I can imagine its easier to manage the angle of the rollerdelayed than to fine trim the lever. Very interesting this videos. :)
I really appreciate the scientific/enginering take of "Forgotten weapons" other content creators only lift out the obvious features in a design and very often have a limited deeper understanding of the design process and features actual function. Tack Ian!!
Ian, your Famas is filthy! Have you been shooting it a lot? ;)
TheGoldenCaulk Yes, yes I have
😂😂😂
Sh shamefur dispray!
That's like a single mag's worth of fouling my friend this is delayed blowback
oh yes, he fired a full load into it this morning...
Ian.....please do a Knights Armory Masterkey video! Was mad I couldn't get my hands on one when I was fighting in Afghanistan.
I really like these 'how it works' videos describing different actions
Love these videos focused on the mechanical aspects of firearm design. Very basic, but essential information for firearm enthusiasts! Thanks Ian!
I didn’t know I had questions about lever delayed blowback. Now, I have so many.
Now that ive got access to a machine shop, im beginning my decades long ambition of making myself a famas. Decoding the specs is one of the hardest parts, finding a source for heat treating the necessary parts is another issue
If I ever figure it out and get it working I'll post a video on it, probably not any time soon
We need a modern PCC using this.
YES!
I used to work for a gun smith that built a 308 lever delayed blowback. So a PCC might be on the table for this.
It really does seem like a good idea for SMG's and PDW's. Yet it never caught on, which makes me wonder if anything is wrong with it.
I didn't know that I had questions about lever delayed blowback systems!
In simple terms. The Lever is what locks the Bolt into a Locking Shoulder.
And the lever is held down by the Bolt Carrier.
When the gun fires, the Bolt Carrier moves back because of inertia. And it lets go of the lever. Thus unlocking the gun.
I swear the famas bipods look like a couple of ratchets stuck on the side of the gun.
I usually watch these videos before I go to sleep and my tired ass thought that was some sort of gas piston, ww1 style lol
I've watched a whole bunch of Forgotten Weapons (and other channels) yet this is the first time I heard about specifically lever delayed blowback. Great video.
i could watch entire lectures of you explaining how guns work you are smart
Seems the Ruger and PSA 5.7 pistols use this lever delay, thanks for the explanation.
Thank you for such a clear and concise explanation of the lever delayed blow back.
Descriptions and demonstrations of interesting mechanisms are a primary thing I like about this channel, keep it up!
Im really liking these how it works videos. Hopefully this will continue to be a regular video on this channel.
Hay, I just saw a indigogo add for shoes on this video, it's the first add that I have seen on this channel in a long time.
I really enjoy this series it's informative and easy to understand
Very interesting Ian. It's nice to see examples of the different operating systems!
I knew how lever delayed blowback worked to a certain extent due to one of your other videos on the Benelli B76 series of pistols, just not in it's entirety; this video helped to clear it up.
I recall you saying in the Benelli B76 video that you would make a full video on lever delayed blowback in the future, and have been looking forward to it since. Good video Ian, keep them coming.
Cool. I read years ago that the FAMAS used a roller-delayed locking system similar to H&K guns. I didn't know that wasn't true until just now! In my defense, I've never even seen a FAMAS in person, much less held or used one.
Thanks, Ian! This kind of stuff is why I love your videos.
Ce n'est pas un système de verrouillage car il n'y a pas d'interposition au mouvement de l'ensemble mobile fermé sur la chambre du canon, autre que l'inertie de la masse additionnelle...L'expression "delayed blow back"... en francais "ouverture retardée"... est vraie ! C'est l'objet d'un brevet français déposé en 1947 et paru en 1949...L'AAT 52 (mitailleuse ou fusil mitrailleur) utilisait ce principe...avec culasse ouverte !
Au plan de la physique des solides, l'inertie est une FORCE qui s'oppose au MOUVEMENT...Donc il faut écrire : F = M x gamma !
Imaginez l'appareil d'essai suivant : un canon vertical avec la chambre en haut...on met une cartouche en chambre...on pose sur le fond de l'étui une masse M representant un ensemble reculant ou une culasse seule...et par un moyen simple (effacement d'une goupille) on percute l'amorce...l'expansion gazeuse éjectée la balle vers le bas (une plaque ductile amortira l'effet) et l'étui vers le haut...par un moyen simple, un cliquet élastique, on arrêtera la masse M à l'instant où elle atteint son apogée h c'est à dire une vitesse verticale nulle...On obtient ainsi le critère de qualité propulsive de la cartouche : v initiale culasse = racine carrée de 2 gamma x h ! A partir de masses differentes, on peut établir la valeur fondamentale de tout le système reculant c'est à dire la vitesse d'ouverture de la culasse de masse M...Cette expérience m'a permis de tester les lots commerciaux de la gamme .222, .222 Magnum et .233 en plus des gammes militaires et de comparer leurs performances intrinsèques vers l'arrière...vers l'avant c'est connu la vitesse initiale des balles est mesurée par des boucles de détection...On peut faire cela pour tous les calibres...Et on en deduit par le calcul tout un ensemble de critères dimensionnants !
Excellent video as always, Ian. Toggle-locked systems next?
Has Ian done "blow - forward" actions yet?
@@kbjerke Indeed he has, here: th-cam.com/video/rk8G5-cJvR8/w-d-xo.html
I...I somehow wasn't expecting Ian's MAS223. Did not know it had such an interesting firing mechanism!
Absolute artist!
really good mechanical explanation. enjoyed this short vignette.
Ian has been playing with his famas recently! Maybe some cool In Range videos getting ready to drop?
This beats eating crayons any day!
Thanks for the knowledge Ian
Only a few have made it into MAS-production...;-)
nice shot!
FAMAS, o yEA!
So basically it’s the same concept as using a heavy carrier/slide to delay blowback, but mechanically magnifying the weight of the carrier so it can handle large cartridges without a lot of extra weight. That’s neat!
Hmm. The delaying lever bit on the famas is exposed when the bolt is closed. Bet that would end an inrange mud test really quickly. Lots of space for the ingress of mud in working bits.
When i saw the notification i was expecting to see a Danuvia bolt.
Was not disapointed.
I've always wanted to know this one, it always confused me hard.
I'm still confused.
I'm still confused how does pressure get transferred to the bolt carrier if its locked it seems as if the pressure has no way to force the bolt open
@@CenlaSelfDefenseConcepts It's not locked. It's just that for the bolt to move back a tiny bit the bolt carrier has to move back a lot. If you listen to what Iain says carefully he says "the accelerator lever is locked into the receiver", the bolt *is not* locked.
Wow the video that I asked so much for! Thanks Ian, also, nice M43 too.
Can we get one of these for the roller delayed system? Love these little bits of engineering!
That's some clever engineering there...
Nice vid Ian, always wondered what that little "clip" on the side of the FAMAS' bolt carrier was for
VZ58 is a perfect example of this and one of the only ones that made it to mass production, thanks for another great video
The vz58 is a short stroke gas piston gun. Although its locking wedge does look similar to the FAMAS lever.
@@ForgottenWeaponsthat is what I was trying to infer, the Czech's have a very interesting way of designing guns
Has he acquired THE Famas? Awesome.
For the next HDIW, can you do the fluted chamber?
This system would probably work pretty well with the headspace operated system.
Next, advanced primer ignition please.
The FAMAS will forever be the coolest looking military bullpup (I actually really dig the aesthetics of the Kel-Tec RDB). One question I have is: what is the benefit or advantage of using the lever delayed blowback system over something more ubiquitous and presumably easier to produce like a long stroke piston or even the piston/direct gas impingement system of the AR-10 and -15? Was this just a case of France wanting to do something different? I have to wonder if the lever delay system is better than the roller delay system too, for that matter.
A pistol system would put more weight at the front (balance was an important design element in the FAMAS, and it shows) and would make it more difficult to free-float the barrel.
@@ForgottenWeapons thanks for the quick reply! I was not expecting to hear from The Man Himself after asking this question! You've really made my day, honestly.
All the gas system (gas port, gas piston, gas cylinder, op-rod, a spring in case of short stroke) is replaced by a single adjunctive part, the lever.
Surprised it didn’t sell for more, being the unique firearm it is.
In my head, I had conflated lever-delayed-blowback and toggle-locked actions, like the luger. Derp.
Will you do a radial delayed blowback video?
Been waiting for this one!
Ian just wanted to show off his FAMAS. lol
Has there ever been an attempt to fire rounds at super sonic velocities through blowback systems?
Multiple sources say it wasn't done because it's unsafe but I was still wondering if it was ever attempted.
To clarify I'm aware that there are delayed blowback systems that fire supersonic ammo at subsonic speeds.
I am asking about blowback systems (and any of their variants) that might have been built specifically to send bullets down range at supersonic speeds.
Sure, the majority of 9mm submachine guns are simple blowback mechanisms firing supersonic projectiles.
I sure enjoy these :)
I think I've heard on numerous occasions that delayed blowback rifles (or guns in general?) are "dirtier" in the breach area (compared to piston gas operated ones, I guess). And have more violent bolt movement. Is it accurate?
Is that a famas bolt assembly in you pocket or are you just glad to see me?
Anything to show off the FAMAS.
So the reason for being a delayed lever system and require more energy to move the bolt back is to ensure the full release/expansion of the gas (and prevent a gas explosion??) in the chamber when the bullet is fired?
Exactly. The case is still extracted in high pressure but not so much that can destroy rifle or harm shooter.
Lever delay is one of a few ways to keep the bolt from opening too soon after firing. If it opens too soon the high pressure could cause the cartridge case to rupture resulting in injury and/or damage.
Wow, how coincidental, as I just watched the FAMAS video a couple of days ago.
Only a handful of guns, but no need to name any of them.. :)
Would love a video about my service rifle, the SIG 550 :-)
It involves levers, I knew it!
1:02 but why? all I see is a lever that delays the opening of the bolt, I don't see why that lever would make it harder for the carrier to move.
It applies a bit more mechanical counterweight for the gas to push.
@@EuroRhodes My bad, I confused the charging handle's rod with a gas piston when in fact it's right there in the system's name, it's a "blowback" .
It trades mass for speed. To accelerate a mass to double the speed in the same time, you need four times the energy, so introducing a lever that accelerates the carrier in respect to the bolt face, you need less weight than in a pure blowback system. .
Hey Ian, i have a Taurus CT40 G2. Iv tried looking up information on it online but i cant find much. Maybe at some point if you got ahold of one i would love to see a video on it.
Why don't we see this operating system more? It offers the same advantages as a roller delayed system but is simpler and doubtless cheaper to manufacture. It would seem that this system would be especially suited to low pressure cartridges such as in pistol caliber carbines where improvements in weight and recoil could be had over simple blowback.
Nice video. Obviously, the FAMAS is easy to recognize, but what is the SMG? It looks like the Hungarian Kiraly, but i haven't watched that video yet, only seen the thumbnail. Interesting mechanical concept.
What SMG was that bolt from?
Danuvia 43M
It makes so much sense now haha. Its a lever that delays the blowback for the bolt. Hah! its in the name haha.
RIP Famas, it would a pitty to see it being decommissioned.
Does anyone know which machine gun the bolt shown at 1:52 belongs to?
I'm 99% certain Ian could explain any mechanical principle and system using only French firearms.
Since there are St Etienne G3s, I could. :)
I actually wish Ruger had added this to the PC9, it would have made the carbine lighter and more balanced. Not saying it is bad, just this would have been a nice tweak.
Is that the same 43M you made a video of a while back, the one at the IMT? It looks like the same tabletop, and I can't imagine there are that many of the guns easily filmable.
Pcm979 I think Ian clipped some footage from that video to use as an example and just put a new voiceover over it. I’m pretty sure those are the exact same shots as in the first video.
Yes, it's a clip from that video.
Can you combine 2 delaying mechanisms to make a more effective delaying system? Like if you had a roller or lever delayed toggle?
You're the man
What submachinegun bolt is that?
Such videos would be a lot more informative if you mentioned at what point the bullet left the barrel and pressures started to normalize. We all know this is a matter of timing. So explaining the timing would make it easier to understand the mechanism.
You can do the maths yourself.
A Sterling machine carbine, which I was familiar with, has a 7.7 inch barrel [we'll ignore headspacing] which is 0.64 feet.
NATO 9mm goes at about 1800 feet per second.
That's 0.00035 seconds to clear the barrel.
Slowing the breach opening isn't actually the trick, it's making sure there's enough power left in the system to reliably cycle the gun
I suspect that a FAMAS would be a good first project for a 3D metal printed firearm replication / production effort. Lots of moving parts, but few under the highest stress levels and only a few tolerances critical for safe headspacing.
Just that pesky extraction issue...
Joel Rigby Fair. Fluting the chamber isn’t orthodox easy but isn’t that difficult to do either. A little electrical discharge machining perhaps.
What is a fluted chamber? I only ever heard of fluted barrel.
small cuts in the chamber which allow gas to flow around the cartridge case to overcome static friction easing extraction. lots of info on the g3 and its fluted chamber if you want to know more.
When are we going to get a famas mud test?
Can you do a video of the ARWEN 37 ?
have they done with with a pistol?
What submachine
Kiraly 43M
Nice video, maybe next time mention or at least show on screen for one second the names of the guns you used as examples. The FAMAS might be obvious but the SMG isn't as much...
Ничего не понял, но очень интересно!
Isn't this system similar to a roller-delayed blowback system? Don't they both use leaverage to move the bolt carrier? I'm genuinely asking, I just don't know.
Same principle
So is the high extraction pressure the main reason we don't see this mechanism used on more firearms?
The roller-delayed system runs on the same principle and it widely adopted.
I think that what happens is that both the long stroke and short stroke piston design are easier to copy-paste.
What komn87 said. So much r&d has gone into long stroke and short stroke piston design, as well as whatever the system is the AR-15 was again (not direct impingement), that they've taken over as the go to methods, along with some roller delays in the mix (which IIRC were generally thought of as harsher to shoot by comparison to AR-15 and short stroke guns, but I might be wrong). And IIRC in the FAMAS video Ian did mention that while the lever delayed blowback system is very reliable and simple when using the ammo it was designed for, it can be a bit picky about the bullet weights, powder loads and casings, and might require modifications to move from one type of round to another, like how they had to modify the FAMAS to run reliably and accurately with NATO spec brass cased ammunition, vs. the original French steel cased 5.56. You can't simply adjust the gas pressure etc. on the FAMAS to cope with different loads, you can only do things like change the fluting of the chamber, the length of the levers and the mass of the bolt carrier to change the dynamics of the gun.
In theory the system is as safe as pure blowback. It simply exchange the mass of the bolt with the acceleration of a part of it.
In practice, using riflle ammunitions, it's difficult to fine-tune, being always on the verge of having a too harsh extracion (not enough mechanical disadvantage) or not having enough power to cycle the action (too much mechanical disadvantage).
Cool
Love
Any evidence on how durable this is? Seems like not a lot of steel to tame the forces at work. For a .223 may not be an issue. PS: So is the Famas the best of all bullpups?
The same delay mechanism is used in the French AA52 7.62x51 machine gun which is still in (limited) service after over 50 years, so it's probably fairly robust :). (There was even an experimental version in .50BMG).
Have there ever been any attempts to put this system into a handgun or is the system not really conducive to handguns?
Psa rock and some rugers
(Hands Ian some rags and remoil) “here you go buddy” Might clean that a little. Such a dirty dirty video😏
How would it change the perceived recoil, if the lever pushed the mass forward?
I may be misunderstanding but if the lever were acting to push the bolt carrier forward it would act like a simple blowback (Maybe less so since the leverage is now effectively pushing the bolt backwards) until the lever has moved its full travel, then the bolt would rather violently impact the carrier rather than gently following along with it
Delayed blowback mechanism in itself reduces somewhat the feeling of recoil.
@RocketSurgeon AFAIK, the blow forward systems have a terrible felt recoil, though I´m not quite sure why.
I was thinking of some mechanism where the mass is forced forward, similar to the AK101, but where the the bolt has a disadvantage to overcome.
Thinking about it, I guess it would add to the impulse rather than reduce it, but it still boggles my mind...
@@edi9892 Blow forward systems have a huge perceived recoil due to the kinetics changing direction entirely at points in the cycle
If you brace for the recoil coming backwards but there is a forwards lurch then backward movement it has altered your stance and lost the bracing
Delayed blowback however simply softens the felt recoil as you are already braced and it is now a lesser impact over a longer period
Kept you waiting huh