.308 jackets will be about .304-.306... So yes, you will need a press/dies to expand the jacket while pushing on the shot. You can "swage" it together, or with graphite, a common coating anyway, or other lube or teflon or mica or talc or
flour keep the pellets from sticking.
The relative inbalance does not recommend this for long range target shooting but for blasting pests at reasonable ranges... Works great. Glazer. magsafe. Same thought. CH4d,.com has a fairly cheap set of dies for a more blunt bullet. enjoy.