  Why are we poo-pooing full auto? It has it's place - in a crew served weapon. Generally speaking, it's not to kill a lot of people, but rather to deny and enemy UNIT manueverability. It's called "suppressive fire," making the enemy put thier heads down, and reducing the accuracy of thier direct fires. US Army doctrine calls for the use of three-round burst mode once the enemy is on the verge of breaching the lines.  As far as full auto ARs and SMGs go, they have a very narrow tactical application, and anre generally reduced to "spray and pray" use in untrained hands.  You want a bitchin' AR, look up the Barret M-000, sexy, sexy rifle with a sexier round.  