The M4 carbine is a variant of the M16 assault rifle. Developed in 1994 in the United States, it became the primary infantry weapon in the US Army and US Marine Corps, especially its M4A1 fully-automatic variant, which could add the M203 grenade launcher. The weapon has seen action with both the US military and its allies since the Kosovo War in 1998, including the Afghanistan War, Iraq War, July War, and Syrian Civil War.