The M4/M4A1 5.56mm Carbine is a lightweight, gas operated, air cooled, magazine fed, selective rate, shoulder fired weapon with a collapsible stock. A shortened variant of the M16A2 rifle, the M4 provides the individual soldier operating in close quarters the capability to engage targets at extended range with accurate, lethal fire. The M4 Carbine achieves over 80% commonality with the M16A2 Rifle.
The m-4a1 m203 assualt rifle is similar in design and functioning to the M16 family of rifles. Compared to the M16A2 rifle, the M4 Carbine is 1.3 pounds lighter, 6 5/8 inches shorter with buttstock extended, and almost 10 inches shorter with the buttstock collapsed.