Almost had a KB, but not quite

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A bullet stuck in the barrel should not cycle the slide.
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Agreed. It shouldn't. But the fact remains that the slide cycled on the first shot and something caused the barrel to bulge and jam the slide on the second. I don't know that my explanation is correct, but I do know it is the only one that I have or have heard from anyone else.
 
All that pressure still has to vent, and it's all going to go backwards, instead of only a fraction of it going rearwards when the gun fires normally. Keep in mind the case itself can push the slide open, like a rocket. It's not at all surprising a squib load can cycle the slide if there's at least some powder in it.
 
MicroTecniqs, I agree something caused the barrel to bulge. Having jammed a bullet in a 1911 myself though, I can testify that basically nothing happens in terms of slide movement. It's sheer conservation of momentum. The same reason a shotgun blast can't knock someone back 10ft. It would have to knock the trigger man back with equal momentum. Similarly, for the slide to cycle back, something has to launch forward with the same momentum. If nothing leaves the barrel....?

Warden Wolf, if the gas is going backwards venting like a rocket, it would be pushing the slide forward, not backwards assuming we are talking about a locking action such as the 1911. If we are talking about a blowback Mak, different story. Again, it isn't really all that much pressure, or the bullet wouldn't be stuck in the barrel, hence it being a squib.
 
Eldon519, I have had other squibs in a 1911 that did not cycle the slide. This is the only instance that apparently did.

Similarly, for the slide to cycle back, something has to launch forward with the same momentum. If nothing leaves the barrel....?

Warden Wolf, if the gas is going backwards venting like a rocket, it would be pushing the slide forward, not backwards assuming we are talking about a locking action such as the 1911.
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Even if nothing left the barrel, something pushed the slide backward. As Warden Wolf suggested, the cartridge case is driven by pressure against the bolt face and that momentum is imparted to the slide. (I wish I could have recovered the case, but there were several shooters and brass was everywhere.)

Again, I am open to entertaining any other explanation for what happened but in 30 years of describing this, no alternative theory has been put forth.
 
HK: "the second bullet clears the barrel and accuracy is not affected afterwards"

That is advertising hype and definitely NOT always true. IF the bullet of the live round is touching the bullet already in the barrel, the two bullets will PROBABLY (not certainly) be fired out the barrel together with no damage to the barrel. So HK is right? Maybe not.

IF the second bullet gets a running start to build up energy, that energy will be dumped in the form of heat when it hits an obstruction (almost any obstruction, not necessarily a bullet); the heat will soften the barrel metal and the pressure will stretch it like a warm chocolate bar. Then the barrel will be bulged. Depending on where the bulge is, the barrel might be too big for the hole in the slide to pass over it, so the slide won't open. In a 1911, the barrel bushing can be taken out. On other guns, good luck, you may need it!

Jim
 
Something cycled the action is indeed the supposition, the what is what's in question. Only thing I know of that will do that on a 1911 with a squib would be the shooter. Your memory may vary.

I'm not worlds greatest but I learned to load in my early teens and after several decades I've yet to have a round fail (knock on wood). Last year I spent most of my summer tuning a pair of rifles with some trial loads from '89. Proper loading, proper storage and they chronographed same as when I tucked them away. If you've had multiple squibs you may want to evaluate your loading. It can happen, but wow.
 
To my knowledge, I have only loaded 1 squib and that is the one that did or didn't cycle the action. (And no, I did not cycle the action. I'm sure of my memory on that one as I still have my range notes.) I've seen others have squibs that failed to cycle.

We considered the possibility that a single overpressure round may have caused the bulge, but the bulge was half way down the barrel (barrel not including the chamber) and the bulged area was just a 0.5 inch section and rounded, As I said previously it looked like a snake that had swallowed a ball. There was no gradual taper to a maximum diamerter. It was a straight barrel, round bulge, straight barrel.

As to the possibility of an overpressure round, it is a bit hard to believe that double charge (14.4 gr) of Unique would causle just that little bit of damage. And 14.4 grs would almost fill the case to the top and I hope I would have noticed.

OTOH, a short throw while loading could have dropped a partial charge and then the rest in the following case along with the full charge. That would produce a low pressure "squib" followed by a high pressure overcharge, and that combination is consistent with what was observed.

I agree with everyone here and everyone else who has considered this, both at the time and over the years since, that what I have described is highly unlikely, and possibly a unique event. I remain open to any plausible explanation that covers all the elemetns, but have yet to hear one.
 
Quote:
"A Makarov makes more sense for cycling with a squib since it is a blowback firearm. The barrel and slide are not locked together when in battery."

A very good point. Thanks.

V
 
Eldon519, I have had other squibs in a 1911 that did not cycle the slide. This is the only instance that apparently did.
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To my knowledge, I have only loaded 1 squib and that is the one that did or didn't cycle the action.
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So you've had bad luck with factory rounds too or your memory fails you and you've loaded more than one squib? Maybe that's what confused me.
 
As for all the comments about the "locking action" not allowing the gas pressure to blow back the slide, keep in mind that the 1911 is technically a "delayed blowback". There is nothing magical preventing pressure on the bolt face from pushing the slide back. The locking lugs simply delay it until the bullet has already left the barrel. Think about it. If a cartridge pushing on the bolt face can't force the slide open, then how on earth is the gun supposed to cycle? This isn't a rotating bolt design with a gas system. It's still blowback, albeit delayed blowback. And, for that matter, you wouldn't be able to manually rack the slide if it truly "locked". The physics and mechanics of the two actions are exactly the same.
 
A 1911 isn't delayed blowback. It's a recoil operated locked breach gun. The barrel locks to the slide for the first part of recoil.
This isn't a rotating bolt design with a gas system.And, for that matter, you wouldn't be able to manually rack the slide if it truly "locked".
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Tell that to desert eagle owners.
 
WardenWolf, a 1911 absolutely has the slide and barrel locked together when in battery. That is why the locking lugs you referred to have the word "locking" in the name. If a bullet is plugging the barrel, then equal forward and rearward pressure are being applied. That is how fluids work. Since you have roughly the same force forward and rearward on a locked structure, there is no reason for the slide to move rearward. The same way as a pointed out, something like a compressed gas cylinder doesn't move. It has equal force in all directions, so it does not move. The slide is pushed backwards, but by virtue of the stuck bullet (plug in this case), the barrel is pushed forward by pressure, and since they are locked, the forces are equalized.

What makes the slide move rearward is a change in momentum. Momentum must be conserved; it is a law. For something to move rearward, something else must be launched forward with equal momentum. The bullet never went anywhere! It has no momentum, so none can be produced rearward on the slide. Given that the slide doesn't move, the barrel and slide cannot unlock. As I pointed out, when fired normally, a 1911 slide has barely started to move and has still not unlocked by the time that the bullet leaves the muzzle with all the momentum a .45 ACP can muster. A bullet that does not leave the muzzle cannot unlock it. Operating the slide whether by hand or by firing is absolutely what locks and unlocks the slide. Why in the world would you not be able to manipulate it by hand? It's precisely what it is designed to do. The swinging link draws the locking lugs out of engagement as the slide and barrel move rearward together. I would recommend reading up more on how a delayed blowback vs blowback system works. It is all a matter of momentum and inertia.
 
The bullet never went anywhere! It has no momentum, so none can be produced rearward on the slide.
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Not quite true. The bullet did move over half way down the barrel. From the fact that the bullet did move at least that far, we can infer that the bullet had at least some momentum and as you say, an equal amount had to be imparted to the slide. Maybe, just maybe, it was just enough momentum to cycle the slide.

If i still had the barrel I would post a pic so you could see where the bulge was, and the bullet had to be stuck forward of the bulge so you could get an idea of just how far the bullet travelled.

It was the fingers of a Mk IV bushing that jammed on the bulge. IF I had been using a shorter bushing, say a Commander length bushing, the bushing would have been too short to reach the bulge and the second shot would most likely have cycled the slide completely.
 
Three points:
1) keep in mind the slide just barely begins to move, and is still locked to the barrel, as a full-powered round exits the muzzle. Watch slow motion video if you don't believe me.
2) the bullet did move slightly. This is why a few posts back, I mentioned that it would make sense to possibly be slightly out of battery. I was avoiding this because it requires further explanation without changing the fundamentals, but it is a good observation. You are right, the bullet at one point did have an extremely modest amount of momentum (How do we know it was modest? Because it is stuck.) The bullets momentum was also ceased by frictional forces of the barrel which is still locked to the slide. In turn, the slide/barrel assembly which previously has a tiny amount of rearward momentum from the initial bullet movement has "reabsorbed"(if you will) the momentum from the bullet as it came to be stuck, thus pushing the slide/barrel system forward and cancelling the rearward momentum. The net result is zero momentum equilibrium for the system once the bullet is arrested. What you have experienced is a slight redistribution of mass. The slide may have moved ever-so-slightly backwards, but keep in mind it is being resisted by the recoil spring and the main spring via the hammer. Also keep point number 1) in mind to verify that the barrel/slide is still locked. The best comparison I can think of (minus the spring resistance) is a man taking a step forward in a canoe. The man will move slightly forward and the canoe will move slightly backward, but the overall result will not leave the man/canoe system with a remaining momentum once the man stops walking.
3) we are looking at the bullet and slide/barrel in a complete vaccuum, but keep in mind that the whole handgun moves during recoil further robbing the slide/barrel locked assembly of the full momentum it would receive if the gun were in a vise. This is more or less what happens in limp-wristing; the gun is held too weakly so that the WHOLE gun absorbs the rearward momentum produced by firing keeping the slide/barrel from moving as far as needed in relation to the frame. The larger the moving mass, the lower the velocity for equal momentum. The lower the velocity, the lower the kinetic energy. Momentum is conserved, kinetic energy is not. It's basically why shooting a pistol with 400 ft-lbs of energy does not impart 400 ft-lbs to your hands and wrists.

Just based on your last statement though, a possible explanation could be as follows:
The barrel was bulged in a previous incident, perhaps in the same firing session. Subsequent shots had not been causing the slide to fully cycle to hit the frame (I know mine doesn't always based on how fresh the spring is/what its pound rating is, how fatigued I am, and how powerful the ammunition is). The double-tap that jammed the gun caused the slide to travel further back than it had been, and the bushing contacted the bulge.

Just a possible explanation. How likely is it? I don't know. How likely is it that the gun cycled on a squib? To me, not likely, but I am not the know-all master of the universe, nor the grandfather of physics.
 
Eldon, thanks for that link. It does appear that there are others with experiences similar to mine.

The references to the "TAP, RACK, BANG" started me thinking about how this might possibly have contributed.

Ok, this event occured 30 years ago and at this point in time, I am totally relying on my range notes for the details. Reviewing my notes and parsing them carefully, I see this:

I said we were doing double-taps, Actually, we were practicing the El Presidente drill.

The drill is normally 3 targets. 2 shots each target, reload, 2 shots each target.

Ny notes say the event occured while firing on the second target which would be the middle target of the three. The second time through, the middle target is also the fifht target of the drill, counting in sequence.

It is possible that I was working the drill with a full load out (7+1) and reloading when I ran dry. I did and still do this quite often. This would place my tactical reload between the 4th and 5th double-tap which means before firing on the middle (fifth) target. When firing this drill I randomly change the order in which I engage the targets for the second set, sometimes left to right, sometimes right to left.

It is possible that in the initial confusion and concentrating on the condition of the gun, I recorded the firing sequence incorrectly. It is possible that the squib occured on the last round of the mag, that the slide did not lock, and that I cycled the slide after inserting the fresh mag. As I am left handed, I did not and do not use the slide lock to release the slide, I just rack it with my right hand and I could have done this in the course of a reload without conciously registering the fact that the slide had failed to lock back and thus possibly failed to cycle. If I was firing from left to right at the time, I could well have recorded that as the second target, forgetting that this was on the second set and not the first.

This is another explanation that accounts for all of the factors of the event and explains why I might have recorded it incorrectly. As I said, it is possible. But earlier today (yesterday now) I spoke with a friend who was there that day and his recollection was that it was as I initailly reported it so it is unlikely that my initial accounting here was a product of faulty memory. I think I just had a convergence of the factors necessary for an improbable event to occur.
 
Yeah, sorry to play such the Doubting Thomas, Micro. In thinking about it more, you do hear warnings about target loads getting stuck even at significant velocites (maybe the 500-600 fps range). That is much more velocity than I was figuring into my estimates and probably enough that the initial movement would unlock the barrel and slide from one another since it would be over half the momentum of a normal load, even if just a brief impulse. Once unlocked, the trapped pressure would definitely muscle the slide open.

I'm pretty amazed you keep such detailed shooting records. Do you still keep it up today? I imagine you must compete?
 
Yeah, sorry to play such the Doubting Thomas
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No problem. It was a big help. Rigorous critical peer review makes for good science.

Back then I was competing and keeping sort of a shooter's diary every time I went to the range. These days I just I try to make detailed notes of anything unusual or unexpected.
 
A 1911 isn't delayed blowback.
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Well...Yeah, it is...technically. But I won't argue the point.

I've also seen pigs fly...
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For some people...because they've never seen it happen or because they don't believe it can happen...it logically follows that it can't happen, despite the numerous accounts that it does happen. While I can accept that a few perceived that it was a misfire and instinctively executed a malfunction drill so quickly that they "forgot" they did it...the notion that everybody who has experienced a squib forgot that they did that is a bit of a stretch.

A squib absolutely can cause the slide to move far enough to uncover the magazine and strip another round. I was looking straight at a pistol that did it once. Watched it happen. The shooter was in the quick trigger mode on a plate rack and didn't catch it...and pulled the trigger before I could stop her. The result was a bulged, split barrel and a solidly locked-up pistol.

Maybe the jacket and core separated. Leaving the jacket in the barrel as an obstruction for the next round.
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It happens with cast bullets, too...like the one that I described above.
 
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