The Colt Automatic Rifle-15 Military Weapons System or CAR-15 was a family of AR-15 and M16 rifle–based firearms marketed by Colt in the late 1960s and early 1970s. Due to their compact size, the short-barreled Colt Commando and XM177 versions of this family continued to be issued to the U.S. military after the Vietnam War.
The CAR-15 name was an attempt to re-associate the AR-15 name with Colt, since the AR initially stood for ArmaLite Rifle, the original manufacturer. Colt later abandoned the CAR-15 concept, but continued to make variations, using the M16 brand for military-oriented models and the Colt AR-15 brand for law enforcement and civilian models. However, in present usage, CAR-15 is used as a generic name for carbine-length M16 and AR-15 variants.
Specifically, "Colt Commando" currently refers to the ultrashort 11.5-inch barrel assault rifle of the Model 733 series, marketed as the M4 Commando (formerly M16A2 Commando). By comparison, the M4 Carbine has an 14.5-inch barrel, while that of the M16 assault rifle is 20 inches.