M4 Carbine Gets A Makeover / by RANGE R.A.T.S.

In footage taken at Ft. Riley, KS, Program Executive Office Soldier's Product Manager Individual Weapons explains what it is doing to "up-gun" its standard carbine. Changes include adding an automatic trigger and heavier barrel, and making the gun more ergonomic. Once an M4 undergoes these modifications, it becomes an M4A1.