NO! NO! NO! Where you have gone a little astray is the assumption that because someone sold you "8mm mil-surp" you actually got 8mm cartridges. 8mm DOES NOT EQUAL .308 or 7.62x51!!! 8mm is a different cartridge that is used in the 8mm Mausers that you see advertized everywhere. The 8mm is about the same size as .308 at the back end, but the case is quite a bit longer ... I don't think that it would chamber in a .308 rifle. But ... your ammo purchase is suspect and you should compare those rounds to some real 8mm and real .308 at your local sporting goods store. You want .308 or 7.62x51 nothing else!