[BobWright]

Somewhat unusual and I'm not sure what conclusions to draw:

I examined a burst barrel at my gunsmith's shop recently. The barrel was from a Smith & Wesson .38 Special revovler, and I'm guessing it was a Model 10, 5" in length. Don't know where the rest of the gun was.

The rupture was caused by a squib load, maybe 158 gr. JHP. The first bullet was about 1/8" back from the muzzle, I could touch the nose. The second bullet was jammed up against the base of the first. Immediately behind the second bullet was the most forceful rupture, blown out to a gap of maybe 3/4" or so, and tapering back about two inches to unsplit barrel.

Now, it would seem that the force would dissipate through the barrel/cylinder gap to vent the pressure, maybe cutting the cylinder face and barrel stub. But the point where the barrel let loose was immediately behind the bullet, admittedly the thinnest part of the barrl, but where I would have expected the pressure curve to drop off.

I did not see the remainder of the revolver, nor get to ask my gunsmith about that.

I'd be interested in some explanations/discussion here.

Bob Wright

 

[Oyeboten]

Sounds like there had been a third Bullet, which coincided with the bursting of the Barrel, and, that the third Bullet went out the side of the burst-open part.

I wish we had some pictures of it to review!

 

[dfariswheel]

High pressure doesn't escape out a barrel-cylinder gap as fast as you might think.
You have a lot of gas and it builds up a lot of pressure in a revolver barrel very quickly even though there is a gap between the barrel and cylinder.
The situation gets even worse when a bullet is stuck near the muzzle. Then you have the air in the barrel being compressed between the stuck bullet and another bullet coming down the barrel. The sudden shock wave of the compressing air can do surprising things.
Once the barrel started rupturing, likely the split continued even though the bullet had mostly passed.

A danger in black powder muzzle loading rifles is if you fail to get the bullet rammed down until it's resting on the powder charge.
If you fail to fully seat the bullet and leave an air gap, the barrel will often rupture.
Similarly, you can fire a pistol underwater AS LONG as you make sure the barrel is fully filled with water.
Leave any air in the barrel and it blows.
In this blown revolver barrels case, the "killer" was the air in the bore.

Still, I wouldn't expect the revolver barrel to actually burst unless the barrel was a thin old "pencil barrel" or someone was shooting some really hot, possibly over-loaded ammo.

 

[WIL TERRY]

THAT IS PRECISELY how two bullets act when they meet in the bore unexpectedly, front to back. THAT is exactly how inertia operates. THis is easily demonstrated in any lab with any standard pistol and bullets. The barrel breaks, bursts, due to compression and expansion of the front bullet being impacted in it's rear by the second bullet at high speed. No big deal, you could shoot more until the BBL is full and they'll look much the same.
DO NOT FORGET: The maximum pressure from the propellent and the propellent was consumed COMPLETELY before the back of the SECOND projectile cleared the front of the case.
And so it goes...

 

[BobWright]

THAT IS PRECISELY how two bullets act when they meet in the bore unexpectedly, front to back. THAT is exactly how inertia operates. THis is easily demonstrated in any lab with any standard pistol and bullets. The barrel breaks, bursts, due to compression and expansion of the front bullet being impacted in it's rear by the second bullet at high speed. No big deal, you could shoot more until the BBL is full and they'll look much the same.
DO NOT FORGET: The maximum pressure from the propellent and the propellent was consumed COMPLETELY before the back of the SECOND projectile cleared the front of the case.
And so it goes...

Will Terry,

If I understand correctly what you are saying is that compressed air, and compressed air alone, was the cause of the rupture?

Seems to me the compressed air might have blown out the stuck bullet, as surely that would have offered less resistance than the tensile strength of the steel?

Bob Wright

 

[kenhwind]

Two bullets with no powder followed by a triple charge

 

[Oyeboten]

Or one Squib, followed by 2nd Bullet of normal charge ( which stressed the Barrel )...followed by a 3rd of normal or double charge ( which exceeded the elastic limits, of that section of Barrel ).


I saw a Cut-Away S & W 'M&P' .38 Special one time, pretty sure it was a model of 1902 ( 'Four Screw', pre-five-Screw ) which had six Bullets in the Barrel, each mashed into the one ahead. It was like a stone cold 'Mint' example too.

The Barrel had not split or noticeably bulged.

I think this was some sort of Test Revolver or formal Experiment, as the side of the Barrel was milled away, to half the depth of the Bullets jammed together in it, and done very nicely like a Factory Cut-Away would be.

I find it hard to imagine, that the pressure of the 2nd Bullet, would not cause the 1st, stalled one, to be pushed out of the Revolver Barrel, but, of course, we all know, that is usually not how things go, so...

I guess the Air in front of Bullet No. 2 and behing Bullet No, 1 just somehow squeezes on by the arriving Bullet somehow...maybe the Barrel Bulges out a little, within it's elastic limits, and, springs back...or, in some cases of course, exceeds it's elastic limit, and, does not spring back, or, it splits open even.

I do not think I have ever seen any ( actual or images representing ) Split Open Revolver Barrels from older ( or 1940s on back ) S & Ws or Colts...and or the only ones I have seen, far as I recall, were ( or tended to be ) newer ones which did that, where, the older ones seemed to 'Bulge' instead.


Seems like there were more .32-20 Revolvers with Bulged Barrels, than any other Chambering, too. Which come to think of it, is a lot more thickness of Barrel TO 'bulge' than is the case for .38 or .41 or .44 or .45 of course.

 

[BobWright]

Here are a few photos of the blown barrel:







According to WILL TERRY's explanation, the rupture likely occured while the second bullet was somewhere behind the ruptured area.

My gunsmith told me only a new barrel was required.

Bob Wright

 

[Oyeboten]

Pretty bizzare..!


What vintage was/is this S& W 'M&P'?

 

[jrprich]

That is one nasty looking rupture.
Wonder why the shooter would fire the follow shot(s)? I have always been able to tell when I have a squib just by the feel and the lack of report.

 

[pecosriver]

I rapid fired an Army Special in 38 special because the action was so smooth.I was wearing hearing protection so I didn't notice any thing different.When I saw no hits on the box I was shooting at,I tried to open the cylinder.There was a bullet wedged between the barrel and the cylinder and a bullet was sticking part way out of the barrel.All six bullets were backed up in the barrel. 158 gr.reloads I bought at a gunshow.,There was a slight bulge in the barrel,but no additional damage.A friend drilled out the barrel so it could be removed.I replaced the barrel with an Official Police barrel and it continued to shoot fine.No more rapid firing ,however. I was very lucky that the Army Special is obviously a very strong gun.Confession time----When I first reported this on the Forum,I claimed it happened to a friend.I've since gotten past the embarrassment

 

[BobWright]

Pretty bizzare..!


What vintage was/is this S& W 'M&P'?

I have no idea, never saw anything more that the barrel.

Bob Wright

 

[BobWright]

That is one nasty looking rupture.
Wonder why the shooter would fire the follow shot(s)? I have always been able to tell when I have a squib just by the feel and the lack of report.

My guess is rapid firing.

Bob Wright

 

[skyliner]

Reminds me of a story I read about years ago from someone who worked in a military armory department (I can't find the original, or I'd post it here). It was in relation to a discussion on the strength of various revolver frames and barrels.

The guy mentioned that they had received a 4" S&W model 10 that had been carried aboard a river rat boat in Vietnam. It was completely jammed, couldn't even get the cylinder open at first. Turns out the soldier/sailor who carried it attempted to make his own "soft point" ammo by cutting the tips off military FMJ ball ammo. It was then used in a firefight with attempted boarders-- the jacket stripped off the first round and stayed in the barrel, and the next five rounds piled up behind it, with the last stuck halfway between the cylinder and barrel. The armorer remarked at how the gun had not blown up; the barrel was bulged, but there was no splitting of the barrel or frame. I don't know whether it was a HB model or not.

 

[Oyeboten]

I had a squib one time with a older S & W Snub Nose .38 Special...the Bullet literally bounced weakly off of the Paper Target ( which was taped to a Cardboard Box...outdoor Range ).

Nice thing about a Snubby, most any 'squib', if one were to have one, would tend to exit the Barrel just fine.

 

[Oyeboten]

Bob Wright

It looks like the FMJ Bullet which is visible, ( which would be mashed up against the previous round, which is in the end of the Barrel ) has some of it's FMJ crunched up or roughly peeled back, from it's encountering the ragged split of the Barrel rupture there.

If there was an additional round fired after the visible one, I will guess it more or less exited through the open side then, since the rear of the visible FMJ round, does not appear to have been mashed into.


Unusual that someone would have been re-Loading FMJ for .38 Special...unless this was a factory 'dud' round anyway...or old Ammo who's Powder had somehow deteriorated.

 

[BobWright]

It looks like the FMJ Bullet which is visible, ( which would be mashed up against the previous round, which is in the end of the Barrel ) has some of it's FMJ crunched up or roughly peeled back, from it's encountering the ragged split of the Barrel rupture there.

If there was an additional round fired after the visible one, I will guess it more or less exited through the open side then, since the rear of the visible FMJ round, does not appear to have been mashed into.


Unusual that someone would have been re-Loading FMJ for .38 Special...unless this was a factory 'dud' round anyway...or old Ammo who's Powder had somehow deteriorated.

Neither bullet was a FMJ, both were JHPs. I think the jacket of the second bullet split when impacting the base of the first round.

From my information, only two rounds were fired, the first squib, then the second round.

Bob Wright

 

[jimmyjlofton]

At indoor ranges where several firing lanes are in use, and every shooter wearing ear protection, it is quite possible not to hear a squid round especially with light target loads.

 

[Oyeboten]

Neither bullet was a FMJ, both were JHPs. I think the jacket of the second bullet split when impacting the base of the first round.

From my information, only two rounds were fired, the first squib, then the second round.

Bob Wright

Ahhhh, okay...JHP...not FMJ.


What I can see, it does not look like the FMJ jacket had split from mashing up against the lodged Bullet in front of it - it looks like Jacket material crinkled back or torn back by the upper open edge of the burst Barrel...since the Jacket material is scraped up on to the cross-section of the open Barrel split there.

This does suggest then, that the opening-up of the Barrel , was running ahead of the Bullet we can see.

 

[BobWright]

A little off the topic, but in response to a comment about being unable to hear a squib load while wearing wearing protection such as ear muffs: Not too long ago I was on a range where the shooter next to me was shooting a Hawken rifle replica. I marveled that even though I was wearing hearing protection, I could still hear the cap pop before the rifle fired. It not unlike the sound of a bullet passing over prior to hearing the muzzle report. Sort of "pop BOOM!"

Bob Wright