doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrel Burst- Beretta 682?

My cousin's son had a ring bulge at the end of the chamber of the right barrel of his almost new, vintage Sears Laurona. He to was shooting cheap factory loads. I do not remember the exact manufacturer. but the only possibility I could come up with was a base wad separation. It is good that barrel held as he shoots left handed and it would have been right in front of his face. Sometimes we loose focus and don't think to glance into the bores when reloading. I wish the injured party well, and am trying very hard not to make snide comments about dangerous modern guns that are proofed etc. but I won't. Sorry it had to happen.

There have been a number of threads on Trapshooter.com regarding both barrel bursts, and what have appeared to be catastrophic explosions destroying entire guns. Some posts have been illuminating but many simply a repetition of the unknowable and unsubstantiated

Anyway, here are 3 for those interested:
Shotgun Blowups
http://www.trapshooters.com/threads/shotgun-blowups.244114/
Smokeless Powder DDT (I am a believer therein but THIS EVENT WAS NOT DDT)
http://www.trapshooters.com/threads/smokeless-powder-ddt.245629/
Base wad obstruction
http://www.trapshooters.com/threads/base-wad-in-barrel.220936/

Bruce Bowen's experiment is referenced, and he was using a H&R single barrel. His failure to burst the barrel, and Sherman Bell's effort published in DGJ show the intrinsic safety margin of UNOBSTRUCTED barrels
DGJ, Vol 18, Issue 1, Spring 2007 -
1. Destructive testing on a Damascus barrel with thinned walls; calculated by O.D. - I.D., not measured
2. Destructive testing using various obstructions, including a 20g shell
3. Destructive testing using a shell loaded with 3 1/4 Drams by volume or 56 grains of Unique (similar to �Infallible�) with 1 1/4 oz. shot.


"where the empty cartridges went"
Just wanted clarification that BOTH cartridges were empty.

I believe the initial event was obstruction in the lower barrel, and at the moment of the burst the shooter involuntarily pulled the trigger firing the top barrel. All this happened in milliseconds, so it's impossible to know. The (presumed) detonation destructions and obstructional bursts that I've reviewed, when both barrels were loaded, have not been associated with the shell in the other barrel firing.
The recoil from the initial burst (unless a double powder handload) is not greater, so it would seem unlikely that the sear would release the top barrel hammer.

One would expect that the shooter would have noticed a shell looking like this Winchester Universal



And can see how the deformed wad could certainly obstruct the barrel



BTW: A study by the Royal Military College of Science, sponsored by the Birmingham Proof House and the British Association for Shooting and Conservation, showed that an obstruction by 2 fibre wads (total weight of 4 grams) was sufficient to bulge or burst a 12 gauge barrel shooting a 28 gram (slightly less than 1 ounce) load. Peak pressure occurred 22mm (.866�) past the leading edge of the obstruction.

Buck Hamlin�s attempt to destroy a barrel, courtesy of Tom Archer
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=422672&page=2

Buck Hamlin was given an extremely well-used damascus barrel Lefever with a burst right barrel just past the forend tip. The barrel wall thickness at the rupture point was .010�, and the chamber was 2 5/8�.
With the intent to rupture the left barrel, Buck measured the bore diameter and started his effort with a box of 2 3/4� 1 5/8 oz. short magnums. After 25 shells the left barrel had no change in bore diameter. He then lengthened the chamber to 3�, and following 25 1 7/8 oz. magnums (lead #2 and BB) there was still no change in bore diameter.
Buck then lengthened the chamber to 3 1/2� and used 3 1/2� 2 1/4 oz. lead turkey loads. The left barrel blew after only a few shots. The wall thickness at the rupture point, which was almost aligned with the bursting point of the right side tube, also measured .010�.

Note this statement in Drew's post. This would explain why the two bulges are not exactly aligned. Burrard explains it by the fact when the charge hits the obstruction & is checked by it, it is in fact still moving very rapidly. The charge has actually moved forward before the pressure stacks up sufficiently to cause the bulge. This would seem to be the exact situation here as the ring in the top barrel is slightly forward of the one in the lower barrel.
Drew & I Both seem to concur on the solution what more do you want

Joe nailed the best pieces of advise. I have also heard the stories of Fed base wads and have now developed the habit of "blow and peek". Not saying that was the problem, but as widely known as the Fed base wad separation is, I wonder why Fed hasn't addressed it?

Sure glad your buddy is ok Rob. I jammed a piece of re-bar in my hand, in the exact location as his wound, and it wasn't any fun.

There is a lot to be said for his character, as there are a lot of scumbags looking for the money trail.

Best,
Bill

Hello Gentlemen:

I am not an expert, but I will expose my opinion.
I think that the probabilty to ocurr 2 ring bulges at the same event (one in each barrel with a double discharge) is very small.
Why not to think that the problem could be "overpresured" shells?
The shoter was concentrated in breaking clays and he do not notice that his shotgun start to develope bulges in the barrels, then, when the last "overpresure" shot was fired, the barrel finally burst.
Well, please forgive me if I am wrong.
This theory could be easy verified if there are some left shotshells from the same lot/box.

Best,

Here's Sir Gerald's opinion Jose, from the second edition of The Modern Shotgun, 1948, �The Diagnosis of a Burst�

�In order to give the investigator every possible chance of arriving at the truth the gun should be sent up for examination as soon as possible, and without being cleaned. Accompanying the gun should be the fired case of the cartridge which actually cause the burst; if possible the fired case of the round immediately preceding the burst, a few fired cases, and as many unfired cartridges as possible�of the batch which was being used at the time.�

�With this evidence available it should be possible to diagnose the cause of the accident with certainty. By far the most common cause of burst is some obstruction in the bore, and so the first thing to do is to look for evidence of an obstructional (sic) burst, that is for a ring bulge. If a ring bulge is detected the cause of the burst becomes established beyond any shadow of doubt.�

He also observed that lifting of the rib was typically found with a ring bulge.

Ithaca1 Bill Johnson

People that are injured by defective products used in the way they are designed and intended are not scumbags.

The price of a box of cartridges already has his redress packed into the price.

Well, having picked up the barrel group a bit earlier today to actually �fly-speck� it, I can tell you the following:

That the owner and I should have taken a photo of the bottom barrel�s under-surface (near forend lug) as the bulge there is a dramatic 1.35� in width. (I don�t have a digital camera or i-phone here at the moment or I�d provide you all with one, but it looks like the python that swallowed the pig.) The center of that bulge (at its widest 1.35�) is a measured 5- 1/4� forward of the breech�..and I apologize for not having these measurements closer to correct in my first post�..being without tape or tools yesterday.

That the more concentric ring bulge in the upper barrel is .935� at its widest, that occurring right at 5.0 inches forward of the breech in spite of the photos seeming to suggest otherwise. My first glance yesterday left the impression that they were spread further apart. So, in reality the two bulge centers are almost atop one another. Also, the barrel's top rib popped loose from its stanchion just downstream of the upper bulge, and you can no doubt see that the connecting side ribs have been pushed around like spaghetti.

That the first photo (with the injured hand) shows a strap of barrel wall blown upward into the open recess between the two tubes. Though I cannot finagle a micrometer onto it for a more accurate wall thickness number, I can - under magnification � get a pair of needle-tipped dividers onto it for a pretty good measurement. Taken as such, thickness of the barrel wall at 5.0� forward of breech is .095� (+/- .005�) and only .070� thick (+/- .005�) at 6.0� forward of breech. Owner is the original purchaser of the gun and had no aftermarket work done such as forcing cone lengthening, etc.

I promise I�ll leave it at that, but thought you should have the better data to surmise from. We know not to expect anything too conclusive as to actual cause without the fired hulls having been recovered.

Again, much appreciation from this end for those who weighed in with thoughts and well wishes��

Rob

Thanks for the extra effort Rob. Those wall thickness numbers are well within the CIP recommendations

Commission Internationale Permanente pour l'Epreuve des Armes � Feu Portatives (C.I.P)
Standard CIP proof pressure of 850 kg per sq. cm. (BAR) = 13,920 psi proof pressure = 10,730 psi service pressure (SAAMI)
Shotgun recommended minimum wall thickness (p.4) for Standard Steel with tensile strength 700 - 849 N/sq. mm = 101,526-123,137 psi
http://www.cip-bobp.org/sites/default/files/new_file/A-4-1_EN.pdf

10 & 12g
End of chamber - .079�
4� from breech - .075�