Ask to see the ammo he shoots out of it. The SKS shoots a .7.62x39 round and I've never seen it chambered for anything else. 7.62x39 is technically .30 caliber, but there are many different .30 caliber rounds. the 7.62x39 is not interchangeable with any other .30 caliber round.
Technically they're .310"-.311" not the standard .308" that we're use to calling "30 caliber" but that being said Ruger does make their Mini-30's with .308" rifling so they're a bit different then the Com-Boc weapons.
Yes I ran about 60 rounds through it no problems whatsoever. It has after market stock and original hand guard. Don't know what I am going to do about that yet. I have attempted to load a pic but the app on my phone keeps saying that it is crashing.