RedofTx,
Your rifle was built from a surplus military action by someone in or around Zella Mehlis and was proofed in June 1932, with the ledger number 427. The 7.9/57 means it is 8x57, but could have either .318" or .323" groove diameter. You can "slug" the barrel to determine which. If you fire a cartridge in it and a .323" bullet will go into the fired case, base first, without effort, you can load it with .323" bullets.
Mike