That was the Standard bullet weight of the 8x57I (.318") cartridge from 1888 on. Remington 8mm Mauser 170gr loads use compromise .321" bullets and are downloaded from European specs to make them safe if used in I Barrels.Hmm, whatever calibre it is, it shoots a 216gr steel-jacketed bullet.
I took the stock off, here are the markings I found, the bolts/screws that hold the trigger to the barrel are stamped with the same number that is engraved on the inside of the stockThese CROWN - crown/N proofmarks, indicating use of the "4000 atm proof powder", were used by the Zella-Mehlis proofhouse up into the 1920s, as Long as stocks lasted. There should be more proofmarks and numbers under the Barrel, showing bore/land (not groove/bullet!) diameter, case length, proof date (numbers for month, year) and, if Zella-Mehlis proof, a ledger number for the month. Maybe even trademarks of the gunmaker and barrelmaker. As the bolt is mismatched and Shows no civilian proofmarks, the rifle should be checked as iskra noted.
No there is not anything on the rear wall of the magazine box. thank you very much for the info. Any recommendations for stock repairs, the stock has a crack and I am looking for a trustworthy gunsmithThis rifle was proofed at the Zella-Mehlis proofhouse 2,20 = February 1920, gun number 738 of that month. The Gew.98 large ring receiver was made late in WW1 by the electric equipment concern Siemens & Halske, who forged and machined many such Receivers and sent them to the Suhl and Zella-Mehlis gunmakers to be completed there into the star-marked Gew98 rifles. The many marks under the receiver ring are internal factory quality control marks that documented the many machining steps. The magazine box-triggerguard-set Trigger assembly seems to be a leftover from a commercial rifle of Mauser, Oberndorf, pre-WW1 make, as it shows the typical Long set Trigger mainspring and the trigger parts are set directly into the machined bottom metal, without a seperate housing like the aftermarket double set triggers. Is there another Serial number on the rear wall of the magazine box?