You can get a Mauser for $325 at a gun show, pick related.>>35842075
There's like...a billion of them on GB ATM. They'll disappear on your birthday.>>35843288
Every gun has it's own history. You can't say something like "All the Russian ones will be corroded" without looking stupid because there's plenty of Russian ones that are just fine.
Post-war rifles will probably be in better condition, but Russia made them post-war too.
The exception is Chinese because the Chinese used them extensively post-war, so a lot (but not all) of the Chink Mosins are beat to shit.>>35843610
They don't usually rebarrel them, they just take the existing barrel and modify it. Ream out the chamber more or cut it down a couple inches and basically put a new chamber in.>>35843940
If a pawn shop won't haggle turn 360 degrees and walk out of there.