Your cases shouldn't split unless the chamber has been modified, a chamber cast might answer some questions.
The rifle appears to be a M91 Mosin nagant by the date on the barrel shank and the M91 style front sight blade, 91/30s have a front post built into a sight hood. Its too bad that someone turned what could be a $100-150 rifle into a $50 rifle or something worse. that being said...
can a gunsmith fix that?
...It ain't worth it.