'93 mauser from Oliveti, look at the bolt face, should be squared at the bottom to act as guide comming through bolt races in reciever. 7X57?
The enlarged gas escape looks like two holes drilled connecting to each other. This was done at the arsenal. If over all condition of the gun appears ok, I would'nt junk it. I've shot a couple of deer with '93's, if the cock on closing doesn't bother you, they usually shoot fine.