The M16 is an assault rifle like the AK 47. After completing the game on Hard, you can use the upgraded version of the M16, the M16A2 that has an attached, underslung M203 Grenade Launcher. It has an (unrealisticly) large magazine size of 95 rounds, the largest in the game for an assault rifle. It is accurate, reasonably powerful, and has a fast rate of fire, making it an all round weapon. Actually, the game's version is one of the M16 rifle series, Colt AR-15 A2 Government Carbine.