I've seen Sten mags and "grease gun" mags advertised for dirt cheap prices. Are there any good, reliable semi-auto weapons that use these guns? Valkyrie Arms makes a semi-auto grease gun that costs about $700, but the general consensus seems to be that they are junk. I know the STEN was a submachine gun, but have not heard of any semi-auto carbines that utilize these magazines. I really like the so-called assault weapons largely because they don't batter me to death like high-powered weapons. So is there anything out there that I should consider?