Ok, got some bad news for you.
First, 168gr 30 caliber bullets are .308 in diameter, you need to buy 30 caliber bullets that are .311 inches in diameter.
Second, Re22 is totally useable in your 7.62x54r, however expect very low velocities and quite a bit of sooting as you will have a hard time getting complete burn with such a slow powder. Next time reach for the Reloader 15.
Machine guns are awesome until you have to carry one.