is it true, or just myth?

[Deaf Smith]

How far down the barrel is the bullet before the powder is engulfed completely? What is the pressure like at that point? One could then easily calculate the rough "fixed bullet" pressure level by examining the difference in available volume for the two. Since there is no movement, the rate of powder burn is likely to have no effect on the peak pressure, either, unlike the case for a moving bullet (since I understand all nitro powders have roughly the same energy content & make the same gas volume)

TCB

Think about what you are saying. If they have the same 'gas volume' but there is no place for this volume of gas to expand, then the pressures spike drastically.

Example. Firecracker explodes in you hand while the hand is open. No biggie. But let it explode while your hand is tightly clenched. Now the gas 'volume' will be the same, but with the fist clenched there will be no place for the gas to expand. The pressure will rise so high the hand will be torn apart.

See in the barrel of a gun pressure lowers as volume increases (in this case as the bullet goes down the barrel.) The gun is designed to work with the maximum pressure that the round develops with the presumption the bullet will exit the barrel. If the bullet does not move forward (as happens when a 7.92x57 Mauser round does when it is fired in a 30-06) the gun will blow up.

Deaf

 

[Jim K]

With all that expert testimony, if I didn't know better, I wouldn't believe me, either.

I say I did it. You say I am, well, mistaken. I should be PO'd, but I am just amused at being told that what I have done many times is impossible.

So how many of you guys have done it? Remember, the gun has to be a locked breech; I used a Norinco 1911 and a WWII Colt. The barrel has to be blocked so the bullet can't move. I used a threaded plug, machined at the rear to the shape of the bullet nose. The ammunition was US GI (R A 65).

C'mon, guys, you are calling me a well, stretcher of truth, but NONE of you has even tried to duplicate the experiment.

Jim

 

[grampajack]

With all that expert testimony, if I didn't know better, I wouldn't believe me, either.

I say I did it. You say I am, well, mistaken. I should be PO'd, but I am just amused at being told that what I have done many times is impossible.

So how many of you guys have done it? Remember, the gun has to be a locked breech; I used a Norinco 1911 and a WWII Colt. The barrel has to be blocked so the bullet can't move. I used a threaded plug, machined at the rear to the shape of the bullet nose. The ammunition was US GI (R A 65).

C'mon, guys, you are calling me a well, stretcher of truth, but NONE of you has even tried to duplicate the experiment.

Jim

Not a WWII Colt...please say it isn't so...

 

[barnbwt]

If they have the same 'gas volume' but there is no place for this volume of gas to expand, then the pressures spike drastically.

In an enclosed volume, pressures rise predictably, as in, it can be predicted, calculated, determined, and from that we could actually make a guess as to what would happen.

A kaboom from a double charge is gonna be a whole heck of a lot different than what is being described here, because there is double the energy applied in total to the action, vs. less than half that for a properly working situation. Pressure is roughly proportionate to volume, so the question is "how many more case-volumes is the system normally at when the powder is fully burned?" If pressures are say, 5X higher, a 45acp isn't gonna blow up anything. If pressures are 10X higher, even then we're only into the ~110,000psi range or so, and there's a chance the brass could hold on long enough for it to dissipate through leakage & heat transfer before being squished out around the breech face. I don't know if a normal 1911 even has enough barrel for 10X the case volume, were we to assume powder only finishes burning at the very instant the bullet leaves (lack of fireball in 45acp disproves this). If someone's pulled this off & not blown the case or gun apart, I'm inclined to believe the pressure spike, while dramatic, is clearly not catastrophic (at least, not without other stuff like a fast-moving projectile involved)

TCB

 

[Bobson]

I'm less interested in what the result would be, and more interested in how this bizarre scenario was ever thought up in the first place. How would a bullet ever be completely and perfectly retained after firing under anything resembling normal conditions?

 

[Jim K]

"Dinna fash yousel'," as the Scots say, Grampajack, nothing happened. The barrels were not original; they were old barrels I had bought just for experiments, though they had plenty of rifling left

Deaf Smith wrote, "If the bullet does not move forward (as happens when a 7.92x57 Mauser round does when it is fired in a 30-06) the gun will blow up."

Have you actually done that? I bet not, because (assuming you could close the bolt on the 8mm) the results are not what you think.

Jim

 

[Jim K]

"Firecracker explodes in you hand while the hand is open. No biggie. But let it explode while your hand is tightly clenched...".

Please don't do this; you are in dangerous territory. Firecracker powder is usually a true explosive, a fulminate or perchlorate. I can pretty well guarantee that a moderate size (cigar butt) firecracker will blow off at least some of your fingers, and mutilate your hand whether your fingers are open or not.

Jim

 

[rskent]

Jim K
Any chance of a video?

Of the gun I mean. I don't want to see someones fingers get messed up.

 

[RetiredUSNChief]

"Firecracker explodes in you hand while the hand is open. No biggie. But let it explode while your hand is tightly clenched...".

Please don't do this; you are in dangerous territory. Firecracker powder is usually a true explosive, a fulminate or perchlorate. I can pretty well guarantee that a moderate size (cigar butt) firecracker will blow off at least some of your fingers, and mutilate your hand whether your fingers are open or not.

Jim

OK, I don't know about the immovable-bullet-in-the-barrel thing by experience, but I DO know the black-cat-firecracker-in-the-fist thing by experience.

I did it, way back when I was in junior high school back in the 70s. Some kids thought it was funny during lunch recess to throw Black Cat firecrackers at me...the shy, quiet kid.

And it WAS funny to them...right up until the moment I snatched one out of the air with my hand and held it in my clenched fist while I looked the guy in the eye as it went off.

Hurt...stung pretty badly. Numbed fingers and a portion of my palm for a while. But other than the black mark and shredded paper in my hand, there was no visible damage. And in a day or two all the pain/numbness was gone.

(And, since I had one-upped the kids considerably, they left me alone.)

I wouldn't recommend that, of course. Pretty stupid. But the common firecracker isn't going to blow anybody's fingers off, even in a clinched fist. A LARGER firecracker? All bets are off.


If anybody wants to set up an experiment with a 1911, there's a cheaper, less costly-to-a-firearm way of setting up the experiment. And that's to use only a barrel.

Since we're simulating no movement at all with the gun parts, then it would be a simple matter to rig up a barrel clamp which would secure the barrel in both the fore and aft positions. Inserting a steel rod cut to size to keep the bullet from moving down the barrel at all would be easy.

Here's how I would do it:

Cut/machine a steel rod, sized to fit the barrel, and just long enough to contact the inserted bullet with the other end flush with the barrel muzzle.

Build a jig which would use two steel blocks firmly bolted to a steel frame. The steel blocks will sandwich the barrel, muzzle to breech, between them.

The breech block, which will necessarily be clamped up against the base of the .45 ACP round inserted into the breech of the barrel, will be drilled out to accept a spring loaded firing pin, which can be tripped by string from a distance.

Set it up in a safe place, start the cameras rolling, and pull the string.


My predictions:

1. The bullet, being soft lead, will effectively deform at the base and swage itself into the barrel and seal it. This is a normal event, but the effect will be magnified since the front of the bullet will not be allowed to move.

2. The brass case will expand in the chamber and seal the chamber from gas leakage between the case and the chamber walls. This, too, is a normal effect, but will be greatly magnified because the bullet and the case will not be allowed to move.

3. The brass case may rupture near the base, as the pressure spike will be too large to contain and will not be "vented" at any appreciable rate around either the bullet or the chamber walls surrounding the expanded case.

4. The primer will flatten in response to the pressure spike and may, depending on how the breech block is designed around the firing pin hole, unseat and possibly partially deform itself into/around the firing ping hole.

5. The barrel will bulge and possibly split around the chamber region in response to the unvented pressure spike. It may or may not "catastrophically fail", with respect to peeling open or flying pieces.


Cost?

A new replacement barrel can be obtained for as low as about $50. I'm sure used barrels could be obtained much cheaper.

The steel for the jig could be obtained for free from various sources.

Common tools and other stuff may be on hand and not cost anything: hand drill, bolts, nail/spring for a makeshift firing pin, drill bits, etc.

And, of course...a video camera.


Heck...I may do it myself, if I can find a cheap used .45 barrel and some time. I'd consider it if I ran across a barrel for, say, $20 or so.

 

[tark]

Hi, Jim. Wondered when you would weigh in. I know you have done it several times. (Well, at least two) but none of us SAW you do it and we are skeptical. Remember, I want evidence admissable in a court.

A little description would help., How you rendered the bullet immovable, stuff like that. Please be a little more detailed.

I know you think we should shut up and go do the test ourselves.... well, I believe I'll take you up on that. I have an old mongrel of a 1911 with S.A. (the Geneseo bunch), and modern colt parts. The barrel is colt. the Frame is Springfield Armory and the Slide is the same.

Post how you set your gun up and I'll set mine up the same way. Better yet, post some pics of the gun, so I can see myself.

 

[RecoilRob]

Lots of people believe that firing a pistol underwater will blow it up...but that's not so and many videos exist of people successfully firing both pistols and rifles without catastrophic damage immediately being done. There HAVE been some AR's that let go dramatically underwater but the AK's seem to tolerate it a bit better.....though this might actually be over-stressing things enough to begin the process of destruction that will happen after more cycles of even normal pressures. It only takes ONE excursion well into 'Danger'-land to damage and turn a limitless durability into a finite one that WILL fail eventually.

We were told in Water Survival Qualification during Marine Bootcamp that should you be in the water and large toothy type fish should be harassing you...to put the .45 close to them and let them have it. They stressed that nothing bad would happen to the gun and if you fired close enough the fish would have a bad day...which sounded fine with me. So perhaps the .45 ACP isn't like a super-high pressure round and could very well tolerate things that would wreck other guns. I'd like to see the test though!

The Ruger P-85 demonstrations were pretty interesting when they first brought out the gun. Fired a bunch of ammo (20K sticks in my mind) with no wear, then they sliced the slide through front and rear of ejection port on one side so there was only one rail holding it together...then fired another 20K without fail. Then they blocked the barrel with threaded rod about .015" from the nose of the 124 Nato ball and fired it. Blew out the extractor when the case failed and burned the area from the resulting flame but after replacing the missing extractor and spring it went back to working just fine.

The 45 ACP runs at much lower pressures and if the chamber is well supported enough...along with tough enough brass, I'd not bet against it withstanding the pressure though I don't know about how the primer would fare. I've extruded them back into the firing pin hole enough that after 5 or 6 the gun (Browning HP) wouldn't fire anymore because all the extruded bits of primer that had been sheared off when the gun unlocked were blocking the hole. None of those cases showed any signs of excessive or dangerous pressures either. But, of course, these were 9mm's so it doesn't count here.

 

[barnbwt]

Firing underwater has the added issue that you're essentially firing an ultra-heavy 'bullet' as water is driven from the barrel, which I have to assume means the slide comes back a whole lot faster than usual & at higher breech pressures (due to slower moving projectile mass). That, I could see causing some problems, depending on how much timing margin there is.

TCB

 

[Deaf Smith]

Deaf Smith wrote, "If the bullet does not move forward (as happens when a 7.92x57 Mauser round does when it is fired in a 30-06) the gun will blow up."

Have you actually done that? I bet not, because (assuming you could close the bolt on the 8mm) the results are not what you think.

Jim,

No but.. Don't put 20 gauge ammo in a 12. It will blow up the 12 (barrel obstruction.) That one is well known. And...

http://www.leverguns.com/articles/taylor/blowups.htm

"Speaking of P.O. Ackley again, he once took a standard .30-06 chamber, enlarged the throat so it would accept .35 caliber bullets, then seated .35 caliber bullets into the .30-06 and fired them through the .30 caliber bore. Using standard .30-06 charges behind the .35 caliber 180 gr. Barnes bullets, no undue signs of pressure were noted. The bullet was re-sized to .30 caliber by the time it had moved very far, then passed through the rest of the bore easily. But if the cartridge case does not seal the chamber, all that pressure comes rushing back into the action and destroys it. This was a controlled test in a laboratory."

Why Guns Blow Up Part I
http://www.starlinebrass.com/articles/Why-Guns-Blow-Up-Part-I/

"Another cause of blowups is firing a gun with the wrong cartridge. A good example is shooting the 8 X 57 in the 30-06. The 8 X 57 is short enough to chamber, but upon firing it, you are doing two bad things. First, shooting an 8 mm bullet down a 30-caliber barrel is a very bad idea and since the case is shorter, the head won’t be properly supported. If it doesn’t actually blow up the gun, it will destroy the magazine and stock because the gases have to go somewhere. "

Deaf

 

[barnbwt]

There have been Blackout's shot through 223 barrels (and silencers) that didn't do anything catastrophic. It's possible to resist the forces, but always to a point.

This is making think about how we need more squeeze bores, now (best of both worlds for large-bore sabots and necked-cartridge advantages)

TCB

 

[Nuclear]

I've seen the pictures of a revolver with multiple lead bullets stuck in the barrel, but the gas can vent out the cylinder gap.

We've all seen the pictures of Glock kabooms, with the chamber section broken open. We've also seen rifles come apart from bore obstructions, some that you would expect instead to just be ejected or destroyed, like bore sighters or cleaning rods.

The only argument I can see for a 45acp is the low pressure and relatively larger case volume. But even if the gun survived one instance of this, as an engineer I wouldn't trust the gun again until a comprehensive non-destructive exam were made of all pressure and load bearing components.

There is no such thing as a free lunch, all that energy has to go somewhere. The other thing to consider is power, or energy divided by time. Normally a gun has all the time of the bullet traveling down the barrel, and it is then dissipated (mostly). If the bullet doesn't move, the energy is generated over a much shorter period of time (smokeless powder has a positive feedback loop between pressure and burn rate), and then not effectively dissipated.

 

[Deaf Smith]

There have been Blackout's shot through 223 barrels (and silencers) that didn't do anything catastrophic. It's possible to resist the forces, but always to a point.

You mean .300 Blackout through a 5.56 barrel?

How can such a round even chamber?

Deaf

 

[azrn]

this is a waste of time.if you get a bullet stuck in the barrel then stop shooting and get the barrel clear before shooting your next round. you as a shooter will know form the sound of your shot if the bullet even left the barrel. I hope for your sake that you can tell the difference. AZRN

 

[Sistema1927]

Here is what I would say to the person who claims this: "You first."

 

[barnbwt]

this is a waste of time.if you get a bullet stuck in the barrel then stop shooting and get the barrel clear before shooting your next round. you as a shooter will know form the sound of your shot if the bullet even left the barrel. I hope for your sake that you can tell the difference.

Examine just about any surplus 9mm SMG barrel sometime...

TCB

 

[Jim K]

Hi, Deaf:

"That one is well known." Or not. I have done very little work with shotguns, but there are two important differences. One is that there will be space between the shot charge of the 12 gauge and the base of the 20 gauge. The other is that the 20 gauge is not inert like a lead bullet; its own powder charge will be ignited and its shot mass will have an effect.

In the case of the .358 bullets in the .308 bore, that is exactly what would be expected. At even the .45 ACP standard pressure (21k psi), a bullet acts like silly putty as it is forced through a smaller hole. (That, after all, is how bullets are made in the first place!) Have you ever swaged bullets? It doesn't require Superman, just an ordinary bench press.

As to your third example, have you ever fired .308 W in a .30-'06 chamber? What happens? Nothing. In fact, I once saw a man pick up the wrong M1 and fire a full clip of 7.62 NATO without even noticing. (Yes, I have done that too, but in my case it was fully intentional.)

The 8mm bullet is c. .323" vs. .308", but it will still swage down under even moderate pressure (far less than it would take to blow the barrel). Yes, I have done that. Sorry, no blowups. Note that it was done with a LEAD core bullet; I never tried with iron or steel core bullets; I believe the results might be different., but I would not want to say so without checking.
Jim

 

[Jim K]

Boy, barnbwt, I haven't thought of Messrs Ernst August vom Hofe bei Halbe and Hermann Gerlich for many moons (not to say that I continually think about other inventors). For those who may not have encountered the duo, they were German gunsmiths and inventors who developed the idea of the "squeeze bore", a rifle barrel in which the bore diameter was gradually and uniformly decreased from the chamber to the muzzle. The result was that more pressure was put on the bullet as it moved down the bore (or at least that was the theory) leading to very high speed bullets. There was some doubt that such a thing really happened, or if it did, whether it was the result of constricting the barrel or the use of more powder. Whether it really worked or not, the additional cost of making the barrels meant the idea had a short life.

That was in the 1920's and 1930's and I understand the idea was revived at the start of WWII by the German army for an anti-tank/anti-aircraft weapon. Apparently, manufacturing problems killed the idea before it really got off the ground, and it has not been seen since.

Jim

 

[Jim Watson]

See also British Littlejohn Adapter for another take on the squeeze bore concept.
Or the .22-.17 Myra Extruder from Australia, also .22-20 Extruder.
http://fmgpublications.ipaperus.com/FMGPublications/GUNS/GUNS0111/?page=18

Mythbusters blew a 20 ga shell clear through a 12 ga barrel without damage.
Parker did it to demonstrate the strength of their barrels.

 

[Deaf Smith]

See also British Littlejohn Adapter for another take on the squeeze bore concept.
Or the .22-.17 Myra Extruder from Australia, also .22-20 Extruder.
http://fmgpublications.ipaperus.com/FMGPublications/GUNS/GUNS0111/?page=18

Mythbusters blew a 20 ga shell clear through a 12 ga barrel without damage.
Parker did it to demonstrate the strength of their barrels.

Well folks just mosey on over to the rifle board here on THR and I posted about the question of 8mm through a 30-06. You would be interested in replies. Basically it depends on the action strength. Some do blow up. Jacketed bullets ain't silly puddy.

Deaf

 

[barnbwt]

The result was that more pressure was put on the bullet as it moved down the bore (or at least that was the theory) leading to very high speed bullets.

There's actually quite a bit going on;
1) You start with a very large driving area for pressure compared to the projectile weight (it's short & fat) which means it accelerates incredibly fast, just like a sabot round
2) You also have a large diameter whose leverage can more easily get the round spinning without shaving off metal (similar benefit as gain-twist rifling)
3) You end up with a long, skinny projectile
3a) Extremely high sectional density makes it highly penetrative (i.e. tank killer rounds)
3b) Much higher ballistic coefficient for projectile than could otherwise be accomadated by cartridge overall length
4) Just a hypothesis, but there may be sonic flow effects in having the bore taper; there should be no internal shockwaves disrupting flow so long as there is a converging taper, and a similar effect should keep the stagnation layer flow adhered to the walls much thinner and more laminar (generally more efficient)
5) The taper should result in a more constant acceleration curve throughout the barrel travel (pressure will not fall off so quickly compared to a non-tapered barrel of the same starting bore size)
6) Chamber pressures can be kept lower than for equivalent performance from a necked round, due to vastly higher initial driving area on the bullet
7) For solid slug bullets, as they are swaged down, their CG shifts backward rapidly, accelerating the mass dramatically (same leverage acceleration effect that accelerates a roller-delay gun's bolt carrier faster than its bolt head)

So you basically get the benefits of a sabot round, without having to waste energy accelerating the sabot which is discarded before impact, and the powder burn efficiency & throat erosion benefits of a large bore round, but muzzle ballistics of a bottlenecked barrel-burner. Now, on the big guns like the German or Little John, the swaging force was high enough that the bores were short lived (like dozens of rounds, though IIRC the Abrams barrel doesn't last but a hundred rounds or something already). But remember that artillery type rounds are typically quite hard, and very dense, and pressures & temperatures quite high. My hypothesis is that a pistol with a squeeze bore setup could allow a short barrel setup to extract far more energy from a given powder burn, and deliver projectiles that would be impractically long & skinny to fit pistol grip magwells.

You basically load in a number of 45acp or 10mm type cartridges with bullets that have one or two deep cannelures or ridges which are what is squeezed down, probably either a solid soft copper or thick skinned lead bullet (though the dramatic increase in sectional density from the swaging would make ferrous, aluminum, or even polymer core projectiles more attractive than at the starting diameter, for even higher velocity). Loads & fires same as ever, only what's coming out of the muzzle are long, skinny javelins like you'd see from the 5.7x28, only going much, much faster for a given barrel length, and with less muzzle flash due to not being nearly so over-bore in powder burn. The ~2Kfps 5.7 rounds are on the cusp of greatness compared to other service rounds, so a slight bump higher in either velocity or mass or both would definitely put the round in a respectable place vs. 9mm, for instance.

A tapered tank rifle barrel is expensive since I imagine hammer-forging is the only way to pull it off consistently, but the cost of doing so isn't terribly dramatic for a small pistol barrel (and often as not the chamber, rifling, any chamber fluting, and everything else is done all in one whack, so a bore taper would at best make the forming mandrel incrementally more expensive). Might even be a way to get around NFA regs on >50cal projectiles, too, so long as they get formed to under 1/2" in the end. I think the idea might work even better for smoothbores, as far as bullet acceleration & energy efficiency potential, but unfortunately small bore smooth bore guns are just too dangerous for ordinary Americans...

TCB

 

[tark]

Jim K, have you read my latest post, # 35? I have decided to take you up on your challenge. I am ready to try this test on my own 1911. A bastard mongrel of a gun, but with quality parts, Colt and Springfield armory (Geneseo, Ill) parts.

I have asked you for a detailed description of exactly HOW you set up your gun for this test and some pics would be helpful.

Still waiting. Pics.... descriptions... anything?