Had a customer drop of a nice Miroku-built Win 92 (or Browning B-92; take your pick..) the other day. He says he "lent it to a friend" who just wanted to try out some of his special "tough" .44 mag handloads.
Subsequent Warning and Educational Experience Outcome:
DO NOT EVER LEND YOUR: 1) CHAINSAW, 2) RIFLE; 3) HANDGUN; 4) SHOTGUN, 5) WIFE; 6) PRIZED FISHING GEAR, OR 7) ANYTHING ELSE YOU TRULY VALUE, TO A "FRIEND" JUST TO "USE FOR A LITTLE WHILE, HONEST!"
Or, as they used to say in New York City, "WHAT COULD POSSIBLY GO WRONG?".
So, this guy handed me his pretty little '92, but it wouldn't cycle worth a crap. All sticky and such. Then he handed me the fired cartridge, which was deformed almost to impossible levels; the case was almost split horizontally in two, the rim was bent, the primer pocket was enlarged to a huge oval, and part of the remnant rim was extruded down in the location of the kidney-shaped extractor. All in all, we later determined that it had probably exceeded 85,000 psi, since even a 65k .454 Casull round fired in the same rifle chambered in .45LC would likely only tear the cartridge lengthwise.
That Miroku receiver has to be praised all to hell though. Forged I wonder? Or just a real good casting. Well anyhow, after I took it all apart (not for the weak of heart with the new '92's; all little balls, springs and coils, and a loose squirrel running in a cage I swear...) and filed off the new "high points" on the bolt, and cleaned all the bits of brass out (he'd obviously fired a few more that had also partially failed, tho' he clams not..), it cycled nicely, probably better than it had new, since I applied a few gunny tricks to sweeten it all up.
But it looked a tiny little bit like there was a bottom chamber bulge, but then again, my own pristine .45 LC '92 has the same slight pseudo-bulge that may be there by design to help with feeding.
Undt zo... I chambered a light cast-boolit .44 mag load, tied it down into my tripod and fired it with a wire from a safe distance. Kah-Boom. No problem, but it did extract pretty rough and gritty hard, like I was dragging something over rough ground. Then I looked at that cartridge, and it looked like a miniature pickle barrel. Well-swelled in it's midsection. Actually, it measured over .135" of an inch larger than an unfired case! Wow! A bit over "spec", huh?
But oddly, the outside of that receiver is still within spec, and didn't bulge at all. A lever-gun specialist I then spoke to said it probably lengthened rather than swelled, and the whole bbl would not easily spin out. Headspace within the rim would be unchanged, but the distance from the back of the case to the front of the bolt would be subsantially bigger. He said to check it (unofficially) by applying some masking tape (which is about 1 thou. or so thick per layer, roughly) to the back of a new case and see if it would chamber. It should go, up to about (max-max) of 3 thou.+ of headspace clearance, but if I could get a lot more than that, it was stretched. In fact, I could get about 12 thou. in there! Ooops!
So, the fact is the receiver had gotten a lot longer, and when metal is stretched like that, the internal matrix is substantially changed, and probably isn't safe any more, esp. with the high-pressure .44 Mag chambering. We talked about re-chambering & re-boring it into .45LC, but again, that metallurgical matrix change is not worth betting on the structural integrity of your brainpan.
Too bad; I only hope he doesn't just try to sell it at a gun show.... He says maybe he'll just leave it visible in his truck so some thief-idiot can steal it. Kah-boom: gotcha?
Moral: not every stupid error can be repaired.