M4 Carbine

The standard US carbine of the post-Cold-War era — a compact, 5.56 mm direct-impingement select-fire weapon that served across Afghanistan, Iraq and dozens of allied forces.

Overview

The M4 Carbine (and the full-auto M4A1) is a lightweight, magazine-fed, gas-operated, direct-impingement carbine chambered for 5.56×45 mm NATO. A direct descendant of the M16 rifle, it mates a 14.5-inch barrel with a collapsible stock and a MIL-STD-1913 rail mounting interface. It has been the individual weapon of the US Army, Navy, Air Force, Marine Corps, and Special Operations Forces since the mid-1990s, and is widely exported or licence-produced for over 60 allied countries. The weapon remains in large-scale service although the US Army is introducing the SIG XM7 (6.8 mm) to replace the M4 in close-combat units.

Development

Colt’s Manufacturing Company developed the M4 in the early 1990s as a shorter-barrelled evolution of the M16A2, intended for vehicle crews, airborne troops and personnel operating in confined spaces. The original M4 entered US service in 1994 with a three-round-burst trigger group. From the 2011 timeframe, the US Army began converting its fleet to the M4A1 configuration across a Product Improvement Program, replacing the burst mechanism with a full-automatic fire mode and adding an ambidextrous safety/selector, improved barrel profile and heavier-duty extractor. Both Colt and FN America have produced the rifle under US government contract, sustaining a production run that now numbers in the millions estimated.

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