on the end of a 9 lb rifle with 22" barrel, with about 6" of can telescoped back around the barrel, to handle rapidfire with full charge ammo. You'd need 2 lbs of steel scope base, mt, and scope. Such a can will render the rifle useless for anything but slowfire from the bipod or some sort of rest. So choosing 308 means no silencer. No silencer, no .22 unit, no GI rd, parts, mags, no concealment, etc, = stupid for shtf.