If you could take a photo with the bolt closed on a cartridge, that would be helpful. I don't know how you wouldn't be able to see it looking at mine but it could be stretched or something. The bore is one of the best milsurp bores I have so it wasn't shot much or if it was, it was well maintained.
On a side note, I was reading this morning that both Italyand Germany
have proof tested these rifles with 20% over cartridges and they passed. Obviously word of mouth with no evidence to support it.