I have a Mauser Oberndorf sporter that does not have a caliber marking on it. It appears to be 8x57 Mauser. It chambers the 8x57 perfectly but I dont know if it is the J round or S round. The following numbers are stamped on the gun. 240.7,85.8,2. Does this mean anything? Besides me slugging the bore does anyone know what it is? Thanks in advance