Some pretty good minds here and would like to hear from those that have an answer as to exactly how a squib round can cycle the slide and chamber a fresh round in a 1911.
This has been disputed and easy to see how it can't happen.
However it has come up a number of times of it happening, and seeing it happen, so I have to believe it can.
I can only rationalize that it can only happen with a malfunctioning 1911, in addition to a light charge squib.
I'd have to put a no-powder squib cycling a 1911 in the same category with:
"My S&W revolver went off when I dropped it and it shot my wife".
And "The accelerator stuck and I ran right through the liquor store wall".
It didn't happen exactly like the person said it did.
I don't buy the partial-charge squib sticking a bullet in the barrel, and still having enough recoil to fully cycle the slide and load another round either.
I could buy a loose bullet getting jammed in the rifling far enough to pull it out of the case during an immediate action drill.
And the next round feeding fast enough to drive the first bullet into the barrel a little, and telescope the loaded round far enough, to end up with two bullets in the barrel.
But I have never actually seen it happen.
But I have only been shooting & smithing 1911's for about 50 years now, so what do I know.
Hmm. Sounds like a winter project. Too chill and damp to get out and shoot half the day, but a few ptooeys and whacks on the ramrod would be fun and informative. I've got a $40 barrel here somewhere I would not mind abusing.
After having seen it happen... was actually looking straight at the gun when it cycled... with a pistol that had been built by Tommy Abernathy... I'll have to disagree with the notion that it can't happen except with a pistol that isn't functioning correctly to start with.
This is one of those "can't happen" instances that does. Most of us who have worked up loads have gone through the point where the projectile leaves the barrel but the slide only moves back a little before returning to battery. It is hard to imagine what could make the gun fully cycle to eject an empty if the bullet is still in the barrel... but it has.
I didn't see the gun being shot but I have seen an M&P 40 with two squibs in the bulged barrel. The shooter, who was a new shooter, said he didn't rack the slide between shots.
I doubt that you could duplicate it consistently. I have thought that it could be a result of deformation of the bullet where the gas plug gets by but the round stays stuck. I would also think that the round will have to travel a ways down the barrel for the gun to cycle.
Tuner, was the round lead or jacketed/plated?
Not agreeing or disagreeing, just asking for an explanation of how the 1911 short recoil action could unlock and cycle in a fresh round. The squib would be holding the barrel forward with the same pressure that is bearing on the breech face when the pressure dropped to zero. I do believe it can happen, but would like to understand the sequence of events leading up to it, and how to replicate it.
The "correct" or just-right combination of squib powder load, light recoil spring and either a light magazine spring with 1-2 rounds remaining or no rounds (last round squib).
The squib load only has to power the rearward movement of the slide sufficiently for the compressed "light" recoil spring to power the slide forward again, stripping the remaining single magazine round to chamber it. In the scenario of last round squib, there is no requirement for the compressed recoil spring to again drive the slide / strip a cartridge from the magazine, as the slide stop is engaged by the now empty magazine. The danger in the last-round-squib scenario is of course, not recognizing it happened, then load a fresh magazine to yet again fire a round into the now obstructed barrel.
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The "correct" or just-right combination of squib powder load, light recoil
spring and either a light magazine spring with 1-2 rounds remaining or no
rounds (last round squib).
The squib load only has to power the rearward movement of the slide sufficiently for the compressed "light" recoil spring to power the slide forward again, stripping the remaining single magazine round to chamber it. In the scenario of last round squib, there is no requirement for the compressed recoil spring to again drive the slide / strip a cartridge from the magazine, as the slide stop is engaged by the now empty magazine. The danger in the last-round-squib scenario is of course, not recognizing it happened, then load a fresh magazine to yet again fire a round into the now obstructed barrel.
How in this example was the barrel linked down, breaking the engagement with the slide when both the barrel and slide where acted on by the same pressure in opposite directions? Certainly the slide would move slightly if the bullet went half way, but to completely cycle would be a different matter.
Most often the squib does not cycle the slide at all. I have purposely loaded and fired them to no avail, but a stuck bullet in the bore.
It was a 200-grain lead SWC Kruz. The man said 4.5 grains of Bullseye.
He and his wife were sporting his and hers TommyGuns... Abernathy's trademark. I was talking to him while she ran the plate racks, practicing for a match the same afternoon. I was watching her shoot because I was impressed by her mowin' the plates down and with her recoil control... standing behind and slightly to her right... when I heard the light report. A plate didn't fall and I didn't see a strike in the dirt berm. I did see the empty case dribble out... and before I could yell for her to stop, she pulled the trigger again.
There was no kaboom. There wasn't even a report. The gun just went pop- pffffft... and locked up. I saw a bullet nose about a half-inch from the muzzle, and the barrel was split up the sides at 3 and 9. I got the slide to move about a quarter-inch and that was as far as it would go.
Like most people, I was skeptical when I heard of it, thinking... like everybody else... that the shooter did a fast tap-rack and simply forgot... until I actually watched it happen in real time. Her left hand never moved. She just pulled the trigger.
I was also on hand for another one, but I didn't see it happen. The bullet didn't make it quite far enough to let the next round chamber... and thank his stars that he was shooting hardball instead of short hollowpoints... and the gun failed to go into battery. When he jacked the live round out and let the slide go... it failed again. He stopped and examined the gun, and found the problem. I knocked it out with a rod that I keep in my range bag, and he carried on.
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How in this example was the barrel linked down, breaking the engagement with
the slide when both the barrel and slide where acted on by the same pressure
in opposite directions? Certainly the slide would move slightly if the bullet
went half way, but to completely cycle would be a different matter.
You're gettin' warm...
Warm, yes it happens with a 1911.
Just perhaps not any 1911.
For reasons that I can only fantasize about the bullet affects a very poor seal as it leaves the case? and an imbalance in pressure momentarily occurs and in the right set up, cycles. Okay great. I can easily debate against this fantasy occurrence. If the bullet goes far enough to allow the next, it was sealed most of the time. There is always an imbalance, the bullet engraving and sliding out the barrel under the same force as the case is being held against the breech face is an imbalance, and causes the side to begin movement and the momentum that carries it through.
Poor or limited radial lug contact to allow the slide to move prior to a full link, down would help to allow it. Direct blow back, weak recoil spring, can do.
Since the thread on another forum, I've been all over the web looking for stories of this happening. I found them with just about all calibers. I've seen posts of first hand accounts of a .22, a few 9's, a .38 (in a 1911), a 40, and more than a few .45's.
There is one consistency in all the reports... lead projectiles. I can't find any "reports" of this happening with jacketed rounds.
I've never given thought to inspecting a stuck bullet before grabbing the brass rod but maybe there is an answer there. ?
Okay, so a scenario would be it won't happen primer only but a low charge, the bullet doesn't seal as fast as normal and the gas jet cuts the bullet directing all the thrust to the breech face enacting link-down and closing cycle, somehow the bullet migrates down the tube leaving room for it's mag buddy. Boom, or psssssssst bulge, burp. Maybe closer to possibilities, of possible happenings.
I just don't see how a "Squib" that leaves the bullet in the barrel can cycle a 1911.
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There is one consistency in all the reports... lead projectiles. I can't
find any "reports" of this happening with jacketed rounds
Maybe I should repeat the test with lead, but I just don't see how it would do it.
Okay three different sources have said they had only seen it with lead. Perhaps an important clue. Hard lead and a soft charge is a no-no, just as a hot load with soft. So the hard doesn't obturate with the soft load and gets cut.
In 9mm, it happened to me with a lightly sprung comp pistol and a 125gr JHP.
The bullet went 3/4 of the way down the barrel and the next rd chambered. Really. I heard the different sound and froze, luckily. The RO also heard it and yelled. No noticeable blow-back.
I believe the powder/primer got contaminated by a bad reloading practice I have since ceased to do.
The initial bullet movement and blow-back must have been enough to cycle the pistol?
Jacketed or lead. The only difference is that lead bullets are more likely to drive far enough into the barrel to let the next round chamber.
"What you believe is irrelevant. Stick to the evidence."
Call me a doubting Thomas, but I'm still having a really hard time envisioning how this could happen with a "no powder" squib.
A 1911 or any other locked-breach pistol simply must have enough recoil imparted from the moving bullet to cycle the slide and unlock the barrel from it.
Unless that happens, there is no way the case can get out of the chamber.
A primer only squib doesn't move the bullet fast or far enough to do that.
So that rules out normal recoil operation.
Or blow-back operation either, because the slide & barrel are locked together.
Gas cutting past the bullet leaving it stuck in the barrel doesn't float my boat either.
If the bullet never reached escape velocity due to gas cutting, it didn't produce enough recoil to cycle the slide on a normally sprung gun either.
At least in my mind.
Of course, I didn't believe that about the guy that could load his Glock by jabbing it foreword through the air real fast during the draw either, until I saw it!
If I can grap the slide of my 1911 and rack it, against a spring tension, why cannot a squib produce enough force to cycle the action?
It's right in front of ya, RC. So simple that you can't see it because you're lookin' for a zebra amongst the horses.
Here's the explanation.
If the bullet moves, the slide moves. The slide only has to move a quarter inch to drop the barrel. Once that happens, the bullet's location is irrelevant. If there's a little pressure left in the system, it escapes through the open breech... giving a "POP" that leads the shooter to believe that the round fired normally. The slide moves, and the shooter believes that the gun has recoiled normally. If the bullet goes deep enough to allow another round to chamber... and he's in the trigger-pull mode... he pulls the trigger.
If there was enough force to drive the bullet halfway through the barrel, there was more than enough to drive the slide fast enough to give it the momentum needed to overcome the recoil spring.
The slide doesn't require a lot of force to cycle without the bullet's influence. You can hand-cycle it as fast as it moves when it's fired... or faster if you're reasonably strong and quick. Try it.
Force requirement demo:
Dump 10 grains of Bullseye into a primed case and stuff a piece of cotton on top to hold the powder in place so you can work it into the chamber. Fire it. You may be shocked to see how far the side will move. I got one to put a hammer on half-cock with 6 grains once... with a piece of toilet tissue lightly holding the charge. The gun had a 16-pound recoil spring... a 23-pound mainspring... and a 1/16th radius on the firing pin stop.
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, 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.
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.
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...
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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
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.
Very well and clearly put Jenrick.
Better yet, whack the bullet from the front with less pressure, and watch the slide move.
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Better yet, whack the bullet from the front with less pressure, and watch
the slide move.
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.
The barrel being locked to the slide was a given.
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just doubt it would be easy to replicate, which isn't any evidence that it
doesn't happen.
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.
Now then... Anybody wanna take a shot at how the barrel gets bulged when a live round is fired behind a stuck bullet?
Just FYI... Stainless barrels bulge and split. Carbon steel barrels only bulge.
compressed air?
Wow! We've got a winner already! Kudos, Chuck!
That will happen when you compress that little column of air... enough pressure to bulge a barrel...
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 kinetic energy dump.
Barrels have been sectioned after being subjected to this and found to have 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 layman's 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.
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.
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There is heat, but not enough to anneal the barrel.
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 slide is moving before the bullet exits... Fun stuff.
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And in the 1911, the true reason the slide is moving before the bullet
exits
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 Newton's Law?
No sweat agreeing on the slide moving. Its in the video.
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.
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These are all one mass now, driven rearwards by pressure exiting the barrel,
forward of the bullet.
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)
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)
Ok, then we'll go back a little.
Let's for the moment ignore the gas effect created when the bullet leaves the case and start immediately after the bullet obturates.
You now have the bullet, case, barrel and slide locked together. In reality they are already moving due to the event Log described.
But, using a spring piston analogy as you brought up and eliminating any gas effect, you now have pressure expanding,and moving the bullet down the barrel, consequently applying pressure to the air column in front of it. This transferrence of energy and pressure is exiting the barrel and pushing the whole assembly rearward, before the bullet exits.
Quite simple and evident.
You saying it has little effect is where your figuring goes wrong.
Lets say the slide assembly weighs 2 lbs. Spring pressure at 16 lbs. Atmospheric at 15 lbs.
That would mean the air pressure exiting the barrel only needs to overcome 34 lbs of resistance to start the slide assembly moving.
Wanna bet the air pressure in front of that moving bullet is significantly higher than that?
Regardless of how the bullet obtains its velocity in the barrel, the pressure cannot be negated. Thats where your theory goes wrong.
You not only asked the question but answered it as well.
The Lawnmower thing was... well... lost.
Perhaps CW overstated the affect of vacating the air column effects on the slide, often an overstatement is the only way of expressing the influence. "You keep eating like that and you'll kill yourself." Another example of the column of air being pushed out is to hold an air hose and release a short burst, overstated perhaps, not the same, yes, but ponder. That column of air is resistant to the bullets venture out the tube and that resistance is visited on the barrel and slide. A 1911 will fire in a vacuum and will venture that the velocity at bullet exit will be higher in the vacuum, due to not having to push the air out. If you are pushing against something, it is pushing back.
The stock car would be able to attain higher speed if it weren't forcing it's way through the air's resistance. No?
I see what the points are. I just disagree strongly with the notion that the gas blowby initiates the slide's movement... or that it even adds anything significant to its acceleration during the bullet's trip. Unless I'm reading it all wrong, that seems to be CW's theory.
Whatever it adds... and I know that everything means something... in this case, it would be so insignificant that it can be ignored. If there was zero gas escaping past the bullet, it wouldn't make a whit of difference in what the slide does.
If we're going to argue that it adds 1/100,000th of a foot-pound of energy... I'll agree... but that would be some pretty serious nit-pickin' and not worth the bandwidth.
I never stated the gas blowby initiates the slides movement.
quote:
"Whatever it adds...and I know that everything means something...in this
case, it would be so insignificant that it can be ignored. If there was zero
gas escaping past the bullet, it wouldn't make a whit of difference in what
the slide does."
This is incorrect. The bullet's velocity, before termination in the barrel,even without blowby, would determine pressure exiting the barrel. Obviously enough additional thrust to cycle a fresh round into the chamber.
This you pointed out very clearly with the spring driven theory.
The blowby is merely evidence of the thrust applied to the breech via the casehead. That is the initial thrust that starts the slide moving. Once the bullet obturates, the momentum is continued by the compression of that blowby and air column forward of the bullet, and exiting the barrel.
..while we have been breaking it down into seperate segments, it really is one fluid event given the time frame it happens in.
The whole impetus was to explain how a squib could be fired and another round loaded. Once the bullet obturates and stops, by your own definition, nothing would happen. My own point was that with enough pressure escaping the barrel forward of the bullet, it can, and explains how it does.
We have wholeheartedly agreed that it does happen.
The mass of the gas (kinda catchy) is insignificant compared to the mass of the moving bullet. Most of the momentum is from the moving projectile. The "bang" starts the motion and the bullet's momentum is conserved by moving the slide back. When the bullet starts moving from the bang, the slide starts moving.
As I see it, the "pregnant question" is how far does the bullet have to move down the barrel and at what velocity to enable the slide to cycle with a XX (pick a number) lb. recoil spring?
I'd say you could easily use a trigger pull gauge attached to the slide to determine how much force is needed to pull the slide back far enough to eject and chamber a round. Simply apply the same amount of force to a lead bullet (or any bullet for that matter) and see how far it goes into the bore. If it goes into the bore past the chamber now you know it's possible and how little energy is needed.
Why should it not? The 1911 is a RECOIL-operated* pistol. And recoil begins the instant the bullet begins to move, so if the bullet moves at all, recoil begins. Since enough slide momentum to operate the gun takes place before bullet exit, any squib load that is enough to move the bullet to the end, or just out of, the barrel will operate the gun and load another round.
With one bullet in the barrel, at or close to the muzzle, and another fired behind it, the result will be a bulged or burst barrel. If, in some way, the first bullet is back against the second, with no significant gap between them, the two bullets will act like one heavy bullet; the recoil will be excessive, but there will be no damage to the gun or barrel.
Jim
quote: the thrust applied to the breech via the casehead. That is the initial thrust that starts the slide moving." Nope. In a recoil-operated pistol, recoil starts the barrel-slide unit moving, not the pressure of the case head on the slide, which only tries to separate the barrel and slide. It can't do that because of the locking lugs.
Pressure on the breech face pushes back the slide on a blowback pistol, but not on a recoil-operated one.
Yep. It does and was widely covered in this thread. If the cartridge doesn't cause recoil, what does?
Recoil is a result of cartridge ignition and the resultant chain of events.
That would be a good start, but you would also need to attain velocity to get a true measure. Thats where it would get tricky.
Good thinking though.
Recoil backward is the result of the bullet moving forward. Of course the bullet doesn't move without pressure, but it is interesting to note that if on, say, a bolt action rifle, the barrel is totally blocked so the bullet cannot move, there will be no recoil.* And if that is done to a M1911 type pistol, the slide will not move.**
Jim
*Hatcher did it with a Model 1903 Springfield.
** My own experiment, using a strain gauge between barrel and frame to prove the slide doesn't move.
You clearly agree with whats stated then. No bullet movement, no exit pressure=no recoil.
Simple.
Glad we could agree on something without petty insults.
I was shooting steel plates with a freind who suddenly found that the slide on his 1911 would not open. He had a bulged barrel which apparently resulted from firing a round after a squibb/semi-squibb load. Luckily he was firing a 45ACP with mild lead bullet loads and the only issue was a barrel replacement.
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I was shooting steel plates with a freind who suddenly found that the slide
on his 1911 would not open. He had a bulged barrel which apparently resulted
from firing a round after a squibb/semi-squibb load. Luckily he was firing a
45ACP with mild lead bullet loads and the only issue was a barrel
replacement.
Good example, all the prime ingredients. The key for me to grasp this anomaly is the pressure that is holding the barrel and slide in opposite directions drops to zero when the bullet stops and the momentum of the slide carries it through.
I didn't know that you can have a squib/semi-squib shot and have the slide cycle completely. Are you sure the operator did not manually operate his slide thinking that it simply didn't cycle properly?
It would seem that there are too many paths for the blowback gas to escape instead of causing the gun to completely overcome the recoil spring force and cycle the next round.
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I didn't know that you can have a squib/semi-squib shot and have the slide
cycle completely. Are you sure the operator did not manually operate his slide
thinking that it simply didn't cycle properly?
It would seem that there are too many paths for the blowback gas to escape instead of causing the gun to completely overcome the recoil spring force and cycle the next round.
The slide isn't acted on by blow back gases so much as the momentum acquired during bullet travel in the barrel. As I'm sure you are aware the slide and barrel travel to the rear .100" and it is a fast .100" travel in which the momentum is imparted to the slide.
My take on it... maybe it could happen.
It would require a precise (or lucky) combination of details.
My understanding of the physics:
The force pushing the projectile down the barrel exerts equal influence on pushing the slide/barrel (cannon) to the rear.
When the projectile stops moving in the barrel, no further force is exerted on the slide/barrel (cannon).
When the projectile exits the barrel, no further force is exerted on the slide/barrel. (cannon).
Once the projectile stops moving or exits the bore, the slide continues it rearward path soley from the momentum given it, in its first 1/8" of movement.
The greater the friction encountered in pushing the projectile down bore, the greater the force exerted on the slide/barrel (cannon).
FWIW, I have deliberately created squib loads that would cause the bullet to stop just short of barrel exit, and I can do it just about every time. The slide cycles almost normally and loads the next round (a dummy - I am not into bulging good barrels).
I don't want to give a powder charge, but a little experimenting will find it.
So, in my test, I needed to have a charge that sent the bullet almost all of the way to the end of the barrel (between 1.5 and 2 Grs) to get my 1911 to cycle the slide and load another round by the logic put forth here. Problem is, charges that got the bullet out of the barrel (2.0, 2.5, and 3.0) did not cycle the slide either, leaving the fired brass in the gun.
I still don't see how a squib that stuck a bullet could cycle the gun.
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I don't want to give a powder charge, but a little experimenting will find
it.
And it'll vary from one gun to the next. I've had better luck duplicating it with 200-grain lead bullets and Unique. Jacketed 230s will cause the slide to cycle, but they don't usually drive quite far enough into the barrel to let the next round chamber.
The slide doesn't have to make the full trip backward. All it has to do is uncover the magazine. If the gun is a smooth feeder, it'll chamber the next one... and if you're in the trigger pull mode, you may not realize that something was wrong. If you hear a light *pop-hissss* you might as well start shoppin' for a new barrel.
It also seems that the common denominators are ammo loaded on a progressive machine and action/speed shooting. Slow fire gives the shooter's brain time to process the bloop and they usually stop and look.
Walkalong... That's the kicker. If the bullet exits...even if it hits the ground 2 feet from the muzzle...the slide won't make a full cycle. Only if it sticks, and just about the mid-point seems to be the sweet spot.
By the way... Thanks for steppin' up, Jim. People were startin' to say I'm plumb looney tunes for tellin' about this little trick.
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My own experiment, using a strain gauge between barrel and frame to prove
the slide doesn't move.
Jim, your experiment/demo was flawed. By using a steel rod against the bullet, and a screw threaded into the muzzle... you locked the system up.
The bullet was pressing on the rod, which was pressing on the screw, which was threaded into the muzzle. The slide didn't move... not because the bullet couldn't move forward... but because the barrel couldn't move backward, and thus, neither could the slide.
In the attempt to demonstrate that Kuhnhausen's "Balanced Thrust/Force Vector" description was wrong, you actually created one.
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The slide isn't acted on by blow back gases...
Well, sure it is. Objects are accelerated by force. In this case, the force comes from the expanding gases... the only force that's available... the same ones that accelerate the bullet. Until the object is moving, it doesn't have momentum. It only has inertia... resistance to acceleration. Momentum is the product of mass and velocity. No motion... no momentum.
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the slide and barrel travel to the rear .100" and it is a fast .100" travel
in which the momentum is imparted to the slide.
The barrel moves backward because the slide is driven backward and grabs the barrel by the lugs and drags it backward with it.
Technically, even the straight blowback is recoil operated. Force forward is force backward. Or... if you prefer... gas pressure forward is gas pressure backward. The only real difference is that the breechblock and the barrel in the blowback aren't mechanically tied together. Aside from that... it's pretty much the same.
See the photo below of an early Norinco barrel with insufficient upper lug engagement. Note the the lugs are deformed on the front faces... because the slide was dragging the barrel backward against the bullet trying to drag it forward. This one only had about .020 inch of lug overlap. The damage was incurred within 200 rounds.
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So, in my test, I needed to have a charge that sent the bullet almost all of
the way to the end of the barrel (between 1.5 and 2 Grs) to get my 1911 to
cycle the slide and load another round by the logic put forth here. Problem
is, charges that got the bullet out of the barrel (2.0, 2.5, and 3.0) did not
cycle the slide either, leaving the fired brass in the gun.
I still don't see how a squib that stuck a bullet could cycle the gun.
I have to agree while a physical test failure does not rule out the possibility it does further raise the question.
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Walkalong... That's the kicker. If the bullet exits... even if it hits the
ground 2 feet from the muzzle... the slide won't make a full cycle. Only if it
sticks, and just about the mid-point seems to be the sweet spot.
By the way...Thanks for steppin' up, Jim. People were startin' to say I'm plumb looney tunes for tellin' about this little trick.
So less power than is required to cause a bullet to not exit imparts more energy to the slide, and cycles it, than a charge that does exit the barrel, and doesn't cycle the slide.
Please explain, why less is more, and more is less.
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I don't want to give a powder charge, but a little experimenting will find
it.
Because I suspect you can't. What would be any kind of violation to share this phenomenon that you have such a great handle on. And why haven't you shown a video since it is so easy for you to duplicate this?
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Please explain, why less is more, and more is less.
Simple. Because when the bullet stops in the barrel, it no longer exerts a forward drag ON the barrel... which means that it also stops resisting the slide sooner. If it's moving, it's moving slow... which means that it offers resistance for a much longer time period. If it keeps resisting during the barrel linkdown, it brings the slide to a stop.
Again... The slide only has to move about .200 inch and the barrel drops. Once the barrel drops, the location of the bullet is irrelevant. It can be stuck in the bore, or it can be a hundred yards downrange... or it can be in China. It's all the same to the slide.
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Because I suspect you can't. What would be any kind of violation to share
this phenomenon that you have such a great handle on.
Log... I don't wanna be a jerk... but if you resort to snark and condescension, I'll delete your remarks. If Jim says that he can duplicate the squib cycle, it's because he can. I've been aquainted with him for several years here, and I've never caught him in a lie. I've done it a couple times, and I won't share the data either... for reasons of liability. If you'd like to experiment, feel free...but you'll have to find it on your own. No two pistols will produce the same results with a given load/bullet combination anyway. Each one is a law unto itself.
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Again... The slide only has to move about .200 inch and the barrel drops.
Once the barrel drops, the location of the bullet is irrelevant. It can be
stuck in the bore, or it can be a hundred yards downrange... or it can be in
China.
Closer to .250" for complete link down, but that distance is not sufficient to complete the chambering of another round. Getting started is not the same as completing the cycle, and falling short.
.250 for complete linkdown to the bed. Less for complete lug disengagement, depending on how tall the upper lugs are.
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.250 for complete linkdown to the bed. Less for complete lug disengagement,
depending on how tall the upper lugs are.
True, but does not mean the slide will cycle enough to eject and load a fresh round. That takes more momentum.
The question is not answered.
Log... You've got people on this thread telling you that it's happened to them. I understand that there was a thread on 1911 forum by a guy that had it happen to him. You've got others here telling you that they've seen it happen. You've got two that are telling you that it can be arranged with a little time and effort... and that they've done it.
I don't know what else it'll take. I give up.
I reckin' I am just going to have to experiment a little more...
Somewhere between 1.5 and 2.0 Grs of W-231, with that particular bullet anyway.
I found it with Unique and a Hensley & Gibbs #68 of my own makin'. I cast'em a little softer than most commercial bullets. Nothing means everything, but everything means something.
Most of the ones that I've had reports of were loaded with the same bullet and Bullseye... and always on a progressive loader.
I did hear of one... but had no contact with the shooter... that happened with Wally World Winchester ball... but the bullet didn't drive in deep enough to let the next round completely chamber.
There's a pretty narrow window with this thing. Might take a while.
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I don't know what else it'll take. I give up.
Didn't say it didn't happen, nor that it can't. Just asked how, I don't believe the contradiction in energy does. I also find it interesting we have just about every wild elusive experience to mankind documented in film and video, but no squib cycling in a fresh round in a 1911. Still, I do believe it could happen, just not near as predictable as has been stated. Why not further the 1911 experience to all and video and explain the requirements for it to happen.
I've tried to explain the requirements, and I probably don't have all of them in spite of wracking my brain 'till my head hurts. I only know that it can... it does... and it happens much more frequently than you'd suspect. I'd heard of it many times before I actually saw it. Like so many other things... they go unreported outside of a small circle of friends, especially if it doesn't result in a damaged gun.
Like you, I couldn't understand how it could happen... didn't believe that it could, and when I saw it happen, I pondered on it long and hard until I had it figured out. It may not contain all the details, but it's the only explanation I could come up with.
Fair enough!