Barrel is shorter...and the muzzle velocity is lower. Aiming a
carbine requires a bit of practice, since its shorter, and the
barrel tends to climb a bit when shooting. The audible "crack" is
much louder and sharper with the carbine, whereas the M16 goes
"blam"... 
Of cos'....its easier to clear SOC with the carbine. Its a good
compact weapon, meant for spec ops, scouts, cdos, armour crewmen,
and anyone that requires an assault rifle sans length and weight.
