I've said it before and I'll say it again, why would you want a carbine in a pistol calibre that negates all the potential advantages of a carbine, such as longer barrel, greater pessure tolerances etc.? The same holds true in reverse. What possible advantage do you get in a sub 16" barrel M-4 that wouldn't be compensated for by the extended burn time, stabalization etc. of the longer barrel? Its not like you're going to stick the thing in your pocket. I don't even know if the .556 was geared for short barrels.It was designed as a RIFLE round. If you want high cap out of a hand gun buy a glock 17 (availble now on this board for just $350 with free oriental bamboo steamer) and a 33rd mag. If you want an assaualt carbine there are many to choose from. Why buy this wierdness and have to put up with all the ATF BS that goes with owning a "short barreled rifle" over this abortion? Buy a 16" M-4 or get a glock with a high cap. Ths just screams "tacitcool bs" to me.
FQ13