Where the scope claw mount is on the receiver ring I can only read "M 1900". The right side of the barrel has the number 295 and a Vienna proof mark. It appears to have been re-blued.I pushed a slug down the barrel and my groove diameter is .326, 4-grooves, and my land diameter is .308 with 4 lands. Left side of receiver is marked "Oesterr.Waffenfabr.-Ges.Steyr. I have shot it again since my first post and it shoots very well with standard .323 bullets. I guess somewhere along the line someone could have re-barreled a 6.5x54 with this 8x56 barrel and then re-blued it.