Ok, just bought an old Mauser from a buddy. It's a 1915 GEW 98 by C.G. Haenel in Suhl, Germany. I assume it fires 8x57 mauser ammo. My buddy never shot it, he got it from his bro-in-law years ago. Is all the ammo for this old rifle corrosive? Am I correct on the caliber? Any help would be appreciated.