doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Blow Up Post-Mortem Part 2

IMO from reloading rifles for a long long time, the shell on the right side of the most recent photo is the one with the highest pressure. That primer was forced back into the breechface and flattened by that breechface. Saw it on rifles all the time. Difference with a rifle brass is you could also measure the sides of the cartridge case as additional evidence of high pressure as well. IMO the overload took the path of least resistance and it appears the metal of the barrel/breech/chamber gave way before the excessive pressure would have pushed the shell back against the left side breechface. Short version of the above is IMO there may have been quite a few over pressure loads involved.

Just the comparison. Here is a picture of primers.
From the left, 10ga RST factory, Rem. Gun Club Factory, Rem. Gun Club with AA209 reload 5800psi.
I personally don't see much difference to the shells in question. Doesn't the upset around the firing pin have more to do with the length and shape of the firing pin? I believe the extrusion you see around the brass cup is a reflection in both photos. Craig

Thanks Craig, and by comparison the subject primer is clearly backed out of the primer pocket slightly. Is the primer cup made of brass or copper?

Youz guys R killin' me but I do appreciate the (contradictory) help. I'll get to measuring this morning, and will work on more ultra close up images of the shell heads, and the indentation made by the extractor which is quite obvious.

I get that recipe, if we use the "ballpark" formula of LUP + 1,000 = psi, as being pretty close to the modern CIP standard service pressure (NOT proof pressure) maximum of 10,730 psi. Higher pressure than I'd want to go in a vintage gun. I've seen the same blown steel barrel as Mark II, and would definitely wonder about a possible double charge.

Drew, thanks for the latest update.
The Mec #32 bushing would be the right one for 17.5 grs of Clays, mine throws on average 17.6 grs. on my 8567 Grabber and 17.4 on a 600 Jr Mark V.

Looking at all the loads available with using a Remington hull, 1 oz. shot, Clays powder, Win. 209 primer and just substituting a different wad, he could have been in a much lower pressure and not in LUP, which is not very informative now.

In my opinion, clays is not a large flake powder and I still do not believe it bridged and threw a double load. If that was the case, one shell out of that box would have had no powder and would have left the wad in the bore.



I am just glad that he wasn't seriously hurt.

Thanks David. I'll take a pic of the powder also.

Several have alluded to the "chrystalline" appearance of the edges of the burst metal. It is my understanding that burst metal, whether damascus or steel, usually has this same appearance. It is the result of the type of failure, a bursting rather than a tearing and not indicating a prior defect in the metal.

Thanks for the suggestion Joe. I measured the steel case heads, just above the rim:
Loaded shell .806"
Empty (from right chamber) .809
Blown shell (from left chamber) .821

I have about an hour of barrel de-resting and scrubbing before I can even start measuring, but this strange wet stuff is falling from the desert sky, so nothing else much to do

I am sure more than a few people have not or do not pick up on the lup not psi data in the Hodgdon Data Center. Worse some may not understand the difference and "assume" which is always very dangerous. I agree that lup data should be separate or have a footnote attached to it to bring its' difference to easy visual recognition.

It is this reason and my natural paranoid nature that cause me to try to verify reloading information by two different sources.

NOW I remember why I hated Chemistry Lab on Thursday afternoon at MU in an old building looking out at the Columns on Francis Quadrangle where coeds were sunbathing and my Frat brothers were starting the weekend early

THAT was an ordeal. Harvesting the shot was pretty easy. The powder however needed to be gently brushed off the bottom of the wad, and out of the shell case. It's very likely a few flakes are still floating around my office.

Shot: .95, .95, .95, and .90 oz.
Powder: 17.4, 17.6, 17.6, and 17.8 grains and what David posted

Barrel scrubbing next.

BTW: was it black powder that the army fed the soldiers to make them impotent? Hopefully inhaling Clays won't do the same thing