The M4, sometimes called the M4 carbine, was a selective-fire assault rifle chambered in 5.56x45mm NATO. It accepted STANAG magazines with a standard capacity of thirty rounds.
The M4 was a descendant of the legendary M16, but shorter and lighter than that rifle, with a telescopic stock. It was favored by counter terrorist and special forces units due to its combination of lightness, compactness and all-around solid performance, particularly in close-quarters engagements. The M4A1 variant had a fast rate of automatic fire and was impressively accurate at all but extreme distances. The rifle used the Knight's Armament modular rail system that allowed the attachment of specialized components such as a detachable grenade launcher, infrared illuminator, night-vision sight, and visible laser. (CTU Operations Manual, 24: The Ultimate Guide, The Game)
In the United States, the M4 saw use by numerous military and law enforcement groups, including the United States Marine Corps and the United States Air Force. ("Day 4: 12:00pm-1:00pm", "Day 9: 11:00am-12:00pm") As of Day 6, the Counter Terrorist Unit used the M4 as the standard assault rifle for its TAC teams, supplemented with a PentagonLight tactical laser light system, a Wilderness Giles 3-point shoulder sling, and a TangoDown forward hand grip. (24: The Ultimate Guide)
- For a full list of appearances in 24, see Rifles on 24.