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

Big castings made from third world steel are terrible for inclusions. Vises, anvils, big gear blanks, etc.
You buy them cheap, and throw 1/3 away.
It's the new world marketplace.

Chuck, did they find the cold lap using MPI? Obviously it leaked at less than proof pressures. And the number of cycles wasn't in the 10's of thousands.

Miller was quite correct when he spoke of seam defects in steel. That is just one of many internal defects that can and do occur in modern fluid steel. There are laps, cracks, porosity, rolled in slag or scale, slivers, other impurities and inclusions, alligatoring, etc. Generally, under the enormous forces of hot and cold rolling, these defects become very much elongated as Bill Schodlatz mentioned earlier. I recall a guy showing me this by tossing a copper penny onto a coil going into a five stand Tandem Mill where the rolling tonnages were around 800 metric tons force on the rolls. The penny ended up as a copper colored smear several feet long and rolled into the surface of the steel.

As such, we are probably getting way out in left field when it comes to what caused the burst in Rob't. Harris' friend's Beretta since such defects are typically longitudinal, and therefore will not develop ring bulges before they finally rupture. The questions here are... what was the obstruction, and was the bulge from that enough to cause a second obstruction in the top barrel, and why did the top barrel unintentionally fire?

But I always get a kick whenever we have a discussion on the safety of shooting Damascus barrels. Inevitably, one or two guys always chime in about the extreme danger of shooting those old tangled masses of welded strips of iron and steel. They seriously think their modern fluid steel is some perfect homogeneous structure. Overall, it is pretty good stuff. But they really ought to take a minute to Google "internal rolling defects in steel" and look at some of the images they will find. Or maybe ignorance is bliss, and we're all very lucky.

Good morning,

Thought I'd provide a quick update re: the burst barrel. The unfortunate owner/shooter does have the remaining 2+ boxes of factory ammo and will be contacting Federal Cartridge to provide lot number and a link to this thread - if only to point them toward a potential risk to other shooters. If they care to read it, they'll have a better description of the matter than him trying to cram it all into a letter to them. Though the SC course people called to say they found some of the pieces of missing forend wood scattered around the stand, there is no hope of recovering the two associated empty hulls.........which sure would have been nice to have.

Also wish we were better at photos here, as we could show you a definite upper barrel dent at six o'clock where the lower barrel wall plowed into the upper tube upon bursting. Keith's second paragraph above pretty much nuts it, and until such things can be known, there'll be uncertainty. The owner is also likely to contact Beretta just as a courtesy to apprise them of the situation, and provide them this link as well.

As for myself, I'm still more fascinated 'why' the bottom barrel rent along the two weld/braze lines connecting the side ribs.....and a few of you might be right about them being more heavily struck along the side ribs. I recognize that a catastrophic event such as what happened in the lower barrel is likely going to have it opening up someway/somehow, yet was puzzled to find the two perfectly linear tears.

If anyone cares at this point, we can keep you informed of how this shakes out once the manufacturers' have been notified. Again, it's very much appreciated that you guys with expertise have taken the time to post has you have......you've provided a wealth of information for sure, and it may be of much help before it's all sorted out.

Thanks again,

Rob

Have been out of the loop, but just finished reading this thread in its entirety. W/o getting into the semantics of terminology and zero pretention about anything on my part, I can add this:

Federal Top Gun hulls until very recently used a wound paper base wad, not a card wad, per se. It was from all appearances the same wound paper base wad used in their paper hulled target loads. There are now Federal Top Gun loads using a different hull w/a separate plastic base wad and a larger dia. primer than the original Top Guns. It was not stated which hulls were in use at the time of failure.

On another note, I know of a catastrophic failure that occurred some years ago involving a single bbl. 12ga. gun and a new factory 32gram target load cartridge that was presumably loaded w/a ball propellant. Said cartridge had been on the dash of a farm/ranch truck for several years.. in the triple digit heat of summer and hard freezing cold of winter and rolling back & forth on the dashboard countless times before finally being loaded to dispatch a snake the owner took exception with. After much thot & discussion, some of it here, we likely correctly concluded that the powder had become 'dust' and it's surface area expanded by some large and unknown amount or multiple and the deterrents, if any had been worn off of the powder's granules and the cartridge had essentially become a bomb, exceeding the gun's receiver and barrel strength [design limits]by some margin. FWIW, the owner was not litigious and honestly, it wasn't anyone's 'FAULT'. Rather it led to a better understanding on our part how it possibly came to occur.

I have come to a better understanding, or perhaps I should say an expanded understanding of the term 'seam' in reading this thread, thanks to all the players/contributors here.

Thankful that the owner did not sustain more serious physical damages. As to exact cause(s), it will likely never be more than conjecture. A ring bulge, to me, says obstruction and once catastrophic failure occurs it would not be unlikely for any trace extreme pressures to work on the next weaker link which might be something like a braze line for a side rib in the immediate proximity. I dunno, but if the joint where the barrels were fitted to the monoblock is damaged as stated, essentially pulling them partially from the mono-block(!), you can bet the pressures involved were off the map for design criteria.

FYI

I have a 12 ga 687 Beretta Barrel that burst in roughly the same place on the top barrel. I was shooting my reloads (Rem STS, Clays, 1oz)I was shooting 5 stand when the barrel let go breaking the forearm. No injuries to myself or bystanders. I never had a squib or any unusally heavy recoil from any other of that lot of reloads.
There was virtually no recoil when the barrel burst.

Excellent job of 'detective' work here Robert! I commend you for your effort. Also thanks for all the other opinions.
I also 'really' wish the fired hulls were in hand!

I think that(possibly) overlapping shear stress might have caused the tear lines to follow the silver braze line between the lower barrel and side plates as they did.

Again as a speculation...... I believe the sear engagement for the upper barrel hammer was jarred free from the violent nature of the rupture in the bottom barrel. Thus firing the upper barrel load which quickly met the upper barrel damage induced by lower barrel rupturing.... This climax causing the upper barrel bulge.

Please keep us informed what you find out Robert!

doubleornothin

True, we're getting out in left field, but the metallurgy education I'm getting is very interesting and informative. I had no idea the kinds of inclusions and defects being talked about - which are on a macro scale, not micro - could even exist in fluid steel. When I worked the line in an iron foundry back in '79 - we made pipe fittings - my first job was with a hand grinder cleaning up sprue and such. We'd get the occasional piece with voids or which hadn't filled the mould entirely, but I don't recall anything like what we're talking about. Thanks to all for the education.

Macro inclusion and void, courtesy of Robert Rambler. 1895 Ithaca Crass with damascus barrels that were being cleaned up for reblueing. Initially just a small pit on the surface of the barrels, quickly grew into what you see here as polishing continued. Inside the barrels are bright and smooth, giving no indication of a flaw.



Machined barrel segment loaded in the tensile machine and fitted with an extensometer at METL. One of the machined segments from a Smith Twist barrel fractured at a much lower tension than the others, and there was a visible inclusion at the fracture. The inclusion was felt to be slag (silicates, phosphorus, sulfur and metal oxides) based on the appearance and Energy Dispersive X-ray Spectroscopy (EDX) spectrum.

Re factory ammo, several years back I received a flat of 12ga AA skeet loads from Winchester. Grabbed a box to take to the range. As soon as I opened the box--which was properly marked--I knew someone had screwed up. High brass heads. Turned out the flat contained one box of buckshot in a box marked as skeet loads. I contacted Winchester with the lot # etc.

With all that was said I still think it was caused by somebody inserting a 20 gauge shell, did not notice and put in a 12 gauge shell. The damage is exactly the same.