The M16A4 is the first burst-fire weapon unlocked and contains a 30-round magazine. It is unlocked when the player obtains 89,000 Assault Score. The M16A4 is a little different as compared to the M16A3, mainly because it is only burst and semi-auto (M16A3 is full-auto and semi-auto). The M16A4 has significantly less horizontal kick, although small increase in vertical kick compared to most assault rifles.
The M16A4 also shares the unlocks with the M16A3, the only other two guns that do that are the M4 and M4A1 for the Engineer Class. Any kills by the M16A3 or M16A4 total together so any unlocks received for the M16A3 will immediately be available to use on the M16A4 and vice versa.
