Hello all, I have an old Mauser that a friend owns, and I am trying to determine what caliber it is. The receiver ring is stamped "Amberg 1918". The serial # is 1327, and the barrel matches the receiver. Now according to all I read online, this should be in one variation or other of 8MM Mauser. BUT, a partial slug of the muzzle gives me .292". Now thats really tight for an 8mm, and really loose for a 7mm. I know they made a .318" bore 8mm, but even those #'s don't jive. Anyone have a theory? Thanks.