http://www.floridaconcealedcarry.com...owulf-interest
It was mentioned above that .458 Socom fits 9 rounds into a standard 5.56 magazine. So a .458 Socom upper would mean you wouldn't need to get rid of any 30 round 5.56 magazines. For as much as some have invested in Pmags a .458 Socom upper might be a legal way to hang on to them.