I am looking at picking up a Black Friday ar, but I don’t know much about true quality/ value like a Honda versus an Acura. I am a single dad with no support from ex dead beat. Are radical arms decent rifles, is Ati the same company as American tactical. I am looking for .556 and eventually .300blk which I read uses the same mags; but how can a 220 grain .300blk round fit in a mag that fits 45-60grain .556 rounds and feed them well. Also do .223 mags hold and feed 5.56 ammo( I am aware that 5.56 rifles will shoot .223 but not the other way around. Any help on this busy day is much appreciated, now that the divorce is over and my cash flow is getting close to positive I will be giving some stuff away on here line I used to. Also I keep reading differing info on if my 7.62x51 can shoot .308 safely or is it the other way around?