Okay, i know this has been on here before, but forgot where i saw it. Anyways, .223 and 5.56, i'd like some help. 5.56 is hotter than .223 right? so .223 can fire out of a rifle chambered for 5.56 but 5.56 should not be fired out of a rifle chambered for .223 right? I've found an AR-15 i like, it's chambered for 5.56 and would like to find stuff out before I purchase.