7.62X54r Chamber issue

[nicholst55]

If you decide to try a reamer, by all means RENT one!

[webfoot10]

Sounds like burned on lacquer from the steel cased ammo. I had a 91/30 that did the same thing. Locked a steel case
in the chamber. I was able to knock the case out after soaking the action in solvent overnight. It would not chamber a
new round because of the burned on lacquer that formed on the shoulder of the chamber. I had to soak the chamber in
acetone to get it to come out, I used a 32 cal. stainless steel torpedo brush to get the lacquer out and it still took a weeks
worth of brushing and soaking to get it clean. Like I said I think it might be baked on lacquer causing the trouble . The
pieces I scraped out were hard as steel. Hope you get it clean.
webfoot10

[CHeatermk3]

Blanco, your OP said "the last time I had it out...", right? So your Mosin developed this issue after it had not been deforming priorly?

If so, then +1 on the Lacquer theory. I'ts what I thought when I read your 1st post.