1911 Squib Cycle

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O.K. then.
I guess you convinced me it "could" happen.

I should go do some experimenting to see if I can get it too.

But I got a ton of leaves to clean up today, and a gazillion more tons on the way!

rc
 
RC, the question does not limit the squib to a "primer only" squib. The bullet is not the only factor as the case/breech face is at the other end, and it is at that end that the momentum is given to the slide and greater, than what the bullet imparts as the bullet is slowing the slide down, not speeding it up. The funny catch in the short recoil is the pressure that imparts the momentum to the slide is also the same pressure that slows it through the bullets drag in the tube.

So, granted the bullet is a required part of the action/reaction, as a blank will not cycle due to low pressure, not imparting enough resistance.

Too many have claimed a cycling squib, to deny it may have happened at all. The how and why is the question.

A major problem is you may go a lifetime without even having a squib, and undoubtedly 99.9% do not cycle. When one does the evidence of why it happened is most certainly lost in an instant.

Okay, I have used the analogy of the 1911 recoil cycle being like a tug of war between equally strong competitors, but one has sweaty hands. Kind of goes like this. They start the pull on signal, and they both have exactly the same strength, only one has sweaty hands, and the rope slips in his grip, but he is still pulling with the same force. What happens is as the one that is slipping moves away from the opponent that isn't slipping who is also moving in the opposite direction. When the sweaty guy reaches the end of the rope the opponent falls back from the momentum gathered during the pull.

So a squib cycle tug of war might leave the loser standing if the rope never got that tight to begin with and he let it slip with just enough resistance for the winning opponent to fall back. The winning opponent will not fall back if the weakling drops the rope on signal as there isn't any stress to begin with.

Saturday morning humor.

LOG

Hadn't seen the last two entries as was taking my time, peck one, peck another. Kinda have an answer now, just doubt it would be easy to replicate, which isn't any evidence that it doesn't happen.
 
My take on a Great thread...

One of the rarely mentioned facts of operation in the 1911, is that , even though there is equal pressure between the breechface and bullet base once the cartridge is fired, There is a small source of pressure still acting on the slide via the FRONT of the bullet and the now sealed pressure vessel Behind it.

Hang in there with me and laugh when Im done...lol

In the following links, if you observe closely, you will see a column of expanding gas and compressed air exiting before the bullet...

http://www.youtube.com/watch?v=EFhGgYq3 ... e=youtu.be
http://www.youtube.com/watch?v=ltyEyNfd ... re=related
http://www.youtube.com/watch?NR=1&v=iTc9Oky4mzA

What does this amount to?
I don't know how to measure it. But its clearly there in every barrel or tube launching a projectile. Its big science and a known quantity in large guntubes. This is what has the slide moving before the projectile leaves the barrel. Its what causes recoil in sealed guntubes. A cannon has recoil before the projectile leaves the barrel and its sealed.

This initial gas in a 1911 comes from the millisecond after ignition and before the bullet engraves the rifling. Its a fact, not theory. This expanding gas, in addition to the compressed air column still has pressure as the bullet seals in the rifling. This pressure is exiting the end of the barrel and applying pressure to the nose of the bullet, and the breach face via the higher pressure between the bullet and case. With the right balance of light load and possible other factors, this force cares not whether the bullet leaves the barrel or not.
Its also evident in the higher pressure signs as a result of short throated barrels. not enough gas is escaping and pressures rise

But its just acting against air right? Yes. But much like the shuttle rockets that we have all seen(best example I could find) what keeps them going at 30,000 feet? thrust against the air mass. Its there and evident.

I think this goes to Logs theory on one slippery side of a tug of war.

If you factor this in to the squib cycling the slide, it becomes more plausible and may further explain how it happens, not if.

I suspect that there are a lot of factors coming together to make this happen.

With a lighter load the case doesn't seal as fast, the bullet doesn't engrave the rifling as quick, and in the milliseconds we are talking about, more gas than normal may escape past the bullet to act on the slide assembly once the bullet engraves the rifling.
Factor in the chance of a long case, overcrimping,undersized bullet, slight bullet deformity of a sloppy reload and light loads due to the application(bullseye/gamers?) and the possibilities rise.
It would be interesting to duplicate.

I suspect the squib cycles others experienced were due to a higher probability of these factors coming together. Nothing more. I also think it could be duplicated mechanically, but thats a whole nother ball o' wax

Thats my $.42 rant....

CW
 
While it does the require just the right circumstances to happen...and those circumstances are different for any given pistol...it happens more often than might be suspected. Most of the time, the shooter catches it before he wrecks his gun...knocks the bullet out, and carries on...and doesn't give it much thought. With the others, the bullet doesn't drive in far enough to let the next round chamber...with the same response. We mostly hear of the ones in which the shooter is doing a fast double, and yanks the trigger before his brain can process the fact that the previous round felt and sounded funny. Those .15 splits can cause trouble.
 
I'd say an easy test/experiment

Take a lead bullet and whack it half way down the bore using a range rod and with one swing of the hammer. Probably a fairly solid whack right? Now place the rod against the breech face (with something to prevent marring or damage to the breech face of course), and give it the same power whack with the same hammer. I'm pretty sure you'll see the slide cycle no problem.

I'm certainly not an expert on the 1911 (or any firearm for that matter), but the idea of equal and opposite reaction seems pretty reasonable in this case.

-Jenrick
 
Better yet, whack the bullet from the front with less pressure, and watch the slide move.
Click to expand...

That's because the barrel will move. The barrel lugs impact the lugs in the slide, and push the slide backward until the barrel hits the vertical impact surface...about a quarter-inch of travel...and it'll stop. You can do the same thing by just pushing on the muzzle.
 
...Illustrating exactly the movement and the little amount of pressure, comparatively speaking, required to keep the slide assembly moving before bullet exit.

CW

The barrel being locked to the slide was a given.
 
just doubt it would be easy to replicate, which isn't any evidence that it doesn't happen.
Click to expand...

Start with 2 grains of Unique and a 230-grain lead bullet. Point the muzzle up to settle the charge around the flash hole before you pull the trigger. Adjust up or down in .1 grain increments until you find the sweet spot.
 
Yep. Think of a diesel engine. Air that gets compressed fast and tight super heats. The steel anneals and expands just a little, and the bullet obturates to fill the gap...which further compresses the air and the cycle continues until the bullet stops obturating. Stainless barrels don't bulge as much as carbon barrels because they split and release the pressure. They show a small bulge. Carbon barrels get a dog knot.
 
I agree with that except for the heat annealing the metal. Even with a kinetec energy dump.
Barrels have been sectioned after being subjected to this and found to have no heat effects other than that imparted when bulged(minor). It is that very thing that allows metals to reach a certain speed, be collided together, and become one without ever melting. Its based on a compounded pressure wave.

In laymens terms its explosive welding, or clad. Part of that study has included studying bulged barrels to discern at what point cladding occurs.

The end result is no heat deformation, just pressure.

Its the same phenomena that allows brass and aluminum to be combined, or any two metals, without melting a thing.
Bulging occurs before a cladding speed can be reached, but its the same principle.

A neat link that helps a little.
http://www.youtube.com/watch?v=QDNX6PcKr7I&feature=pyv&ad=5295696183&kw=explosive cladding
 
I had doubts of the heat deformation theory too, until a guy showed me a bulged barrel that he'd cross-sectioned. It showed evidence of heat, like a HSS lathe bit that "blues" from staying on a grinding wheel a tick too long. I'm not sure if air pressure alone could bulge a barrel to that degree, and a bullet can't obturate unless it has space to flow into.
 
There is heat, but not enough to anneal the barrel. Warm to the touch...maybe. An interesting aspect of that, is that in firing one projectile behind another, both will move, while moving closer together, until the barrel bulges and the pressure drops...leaving a bulge with two bullets, one on either side, and occasionally, two slammed together on the far side of the bulge.
I ,too, thought that a bulge was the result of extreme heat caused by pressure. I was shown otherwise and surprised.

The eye opener was a hardness test of the interior of the bulge when the barrel was split lengthwise.

Compressed air alone would not be quite as dramatic, but the gas escaping around a bullet travels at about...for conversation sake and not exact..
1500-2000? meters a second.

I know cladding can occur at about 2100 meters per second

This would be a fairly low Velocity of Detonation(VoD)

The second bullet is compressing an already highly pressurized area.

The bulge in a barrel caused by a stuck bullet illustrates the moving gas in front of a bullet....And in the 1911, the true reason the sllides moving before the bullet exits.....

Fun stuff.
 
.And in the 1911, the true reason the sllides moving before the bullet exits
Click to expand...

Um...Nah. You've still got a little studyin' to do. If zero gas escaped past the bullet, the slide would still move while the bullet was in transit.

Interesting about the hardness tests after, though. Makes me wonder what caused the bluing in the one that I looked at.

Even though it's slightly off-topic for this thread...I'll do this...once.

Go back to Log man's tug of war analogy, and use a little different mechanism.

Grasp a broomstick in both hands in front of your chest. Pull in opposite directions. Loosen your grip with one hand just enough to let the stick slip. The instant the broomstick starts to slip in one direction, the hand that you loosened starts to slip in the other direction. A simple action/reaction system.

The difference is, or course, that there are actually two action/reaction systems, but the illustration is the same.

To further clarify...the broomstick is the "bullet." The loosened hand is the "barrel." The arm pulling the slipping hand is the "slide."

Note also that while this slippin' is goin' on...both the hand and the stick are offering frictional resistance to the other's acceleration...the same as bullet and barrel offer to each other...and whatever resists the barrel's rearward movement, resists the slide's rearward rearward movement. This is the secret to the delay in the locked breech, short recoil operated system.
The recoil/action spring, the hammer and mainspring, and even the slide's inertial mass take a distant back seat to the bullet/barrel effect in delaying the slide.

The proof of this last statement lies in the fact that you can fire a 1911 pistol repeatedly without a recoil spring without ill effect, and without early barrel disengagement. This, even with a chopped variant like the current 3-inch models, with slide mass roughly half of the standard model.

If you decide to test this, I suggest using a full-length guide rod.
 
...I never said it wouldn't. The escaping, compressed column of air, forward of the bullet, is what drives it even without the aid of escaping gas.

Quite elementary when the videos are looked at
I would suggest doing a little further studyin' yerself!

Explain what the compressed air in front of all projectiles is doing, if not observing Newtons Law?

No sweat agreeing on the slide moving. Its in the video.


CW
 
I've seen the videos. I've also seen the ones that show gas blowby ahead of the bullet...but it's not what lets the slide move...or am I misreading what you wrote?

Hypothetically, you could construct a gun that used a spring to drive the system...with a bullet that accelerates to a mv of 800 fps...and the slide would do exactly what it does when driven by gas and pressure. Gas blowby...or the lack of same...has nothing to do with it. If it did, when a lead bullet fully obturates and seals off the gas...the system would come to a stop.
 
I think we are agreeing from two different directions.
Gas blowby is limited and brief and simply aids what happens forward of the bullet.

I agree with the hypothetical spring driven system.
Once the bullet obturates, you now have an expanding pressure vessel contained by the slide, barrel, case and bullet.
These are all one mass now, driven rearwards by pressure exiting the barrel, forward of the bullet.
Whether spring driven or propelled by gas, the effect is the same, that assembly moves rearward, propelled by the only escaping pressure able to act on it....

:)
 
One realization of visualizing what can't be videoed is the bullet/case separation. The case head is already against the breech face, but the bullet must move forward through the freebore to begin engraving, the case gets a head start. The bullet engraving and sealing says, "Hold on I'm not done yet". And agreed, every nano second of bullet movement, is slide movement.

LOG
 
log man said:
One realization of visualizing what can't be videoed is the bullet/case separation. The case head is already against the breech face, but the bullet must move forward through the freebore to begin engraving, the case gets a head start. The bullet engraving and sealing says, "Hold on I'm not done yet". And agreed, every nano second of bullet movement, is slide movement.

LOG
Click to expand...
I completely agree.
 
Gas blowby is limited and brief and simply aids what happens forward of the bullet.
These are all one mass now, driven rearwards by pressure exiting the barrel, forward of the bullet.
Click to expand...

Uh...I'm a little confused. Explain exactly how gases that are traveling forward under pressure in front of the bullet aid in driving the slide backward? The last time I checked, in order to make an object move in a given direction, I had to apply force in that direction. Your claim is rather like saying that I can mow my yard by running away from my lawn mower.

I understand that gas exiting the barrel at high speed has mass and causes a certain jet effect...but the tiny amount of gas blowby would have virtually zero effect. A little like slapping a stock car as it passes on the backstretch at Talledega. You've added a little...but not enough to make any sort of practical difference on the outcome of the race. OR...conversely...having a fly sitting on the top of the slide when the gun fires. The fly's mass will have some effect on the slide's acceleration...but to what degree?

If we assume that the entire (typical 5-grain) gas plug exits the barrel behind the bullet at 2,000 fps...which I seriously doubt...the recoil impetus of 5 grains of gas at 2,000fps would be roughly equal to an eighth of that imposed by a standard-velocity .22 short.
(32 grains at 1,000fps)
 
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