Daryl S: The bulge I'm talking about doesn't go all the way around the case, it's more of a "bump", so I don't think it's caused by normal case expansion. Also, the bulge and indentation is both the same distance from the base, on the same half of the case if you understand what I mean.
And after finding some better tools to examine the chamber I found some really ugly scratches and markings near the entrance of the chamber that seems to fit the pattern on the fired cases.

To answer you other questions; yes, loaded ammunition chambers without problem, fired brass does not, unless speed was below 1900fps.

Anyway, I have decided to find a capable gunsmith to even out the chamber before I go any further, it feels like this rifle is worth the time and money.
Thank you all for your answers!