What Caused This?

[Singer B]

I acquired a pretty nice 1891 Argentine Mauser a few weeks ago. It is all matching except for the missing cleaning rod. It was in pretty good shape and just needed a new top handguard and a good conservation cleaning/treatment. After I finished servicing it, I took it out for a test fire session using PPU 7.65x53mm Rifle Line ammo. The first round chambered perfectly and the round fired with no perceived problem. When I tried to extract the casing, the bolt was stuck and I had to pound it open. The case was stuck in the chamber and I had to pound it out with a rod. I took the gun back to my gunsmith (who also sold it to me) along with the spent casing. He ran a camera into the chamber and you could see that the chamber had been gouged with some tool and the marks in the chamber matched those on the casing. The edges of the chamber were chipped and cracked. Basically, the gun should not be fired and I have now retired it which is too bad because it turned out pretty nice! My gunsmith did offer me my money back, but he is a pretty good person and the gun still fits in my collection. My question is, has anyone seen this before and if so, what caused it and why would someone do this? Was this part of decommissioning process? Thank you for any information you can provide.

[ssgross]

I've seen several stuck case issues with Mosin's before. In fact there is a YouTube video somewhere of a somewhat popular guy that compares rifles using a plastic hammer to beat the bolt open after every round. The one's I've handled the issue is always caused by prior or active rust and pitting in the chamber.
Owner scrubs out all the active rust till it's clean, thinks all is well, then goes to shoot it. Case sticks, beat on the bolt, shear the rim off the case, then scratches up the chamber trying to get the stuck case out. The correct thing to do is address the issue before all this...after cleaning all the rust out, lightly polish the chamber with a bit of emery cloth on a slotted dowel and a little oil. Not trying to polish out the pitting, just soften all the jagged edges. There was a thread on here somewhere with a video of a guy with a Lee Enfield and a stuck case that he was shoving all sorts of tools in to.

So I don't know how bad your chamber actually is. Could it have been plugged, and then drilled out? Marks on brass can easily look way worse than the chamber actually is, especially if there are burrs. Do you have one of these yet? https://www.amazon.com/Teslong-Bores.../dp/B07XDYN296
It fired fine, and any roughness of the chamber wasn't bad enough to fail your gunsmith's safety inspection. He should have at least peered inside after cleaning it up for sale, and checked the chamber with a field gauge. If there are burrs in there caused by a tool, have your gunsmith chase the chamber by hand with a finish reamer, then lightly polish the chamber, and fire again. Worst that could happen is you get another stuck case, but not stuck quite as bad - assuming he has a proper stuck case remover it's no real time out of his schedule. Best case is the weapon is some sense of serviceable again. If this doesn't work, he should pour a lead plug in the chamber so that 3 owners and a hundred years later the next guy knows there is an issue.

[Aragorn243]

My guess is that it had a plug in it that someone used a rotary tool of some sort to get out. It looks like some of them are pretty deep, not sure that could be buffed out without having case seperation.

[ssgross]

I think you're right on Steve with regards to polishing it, removing too much material. The best I think that could be hoped for is to lightly polish to smooth over any hard edges and see if extraction improves...enough. He did not get a case head separation yet, but that was only one round. Regardless, it will always be terribly hard on brass.

Or....barrels seem to be out there. Found these two in a few seconds.
https://www.ebay.com/itm/364065611756
https://www.ebay.com/itm/304400494262

half dozen or so more when I kept scrolling.

[browningautorifle]

I'd replace the barrel if possible/feasible. That chamber has been opened up so fat you'll always have problems. Who knows exactly what the issue was, what goes on in the heads of some.

[Singer B]

Well, I guess I need to reevaluate this! A $150 barrel isn't too bad since I pay more than that for my AR barrels.

[ssgross]

similarly...
https://www.milsurps.com/showthread.php?t=78433

[Singer B]

similarly...
https://www.milsurps.com/showthread.php?t=78433

I had a 2 stroke go-kart that sounded like that bolt! At least the buttplate cleaned up great!

[browningautorifle]

At least the buttplate cleaned up great!

That was brand new issue...

[jamie5070]

If polishing doesn't work, you could install a sub caliber insert and have an easy shooting rifle.