Colt Commando

XM-177 | GAU-5



USAF airman with GAU-5/A compact assault rifle in 1992.

Source: US Air Force (Tech. Sgt. Marvin Lynchard) - © Public domain

United States
Compact assault rifle
Entered service
Limited service
1965 - 1966
United States - Colt
1966 - 1970
United States - Colt
CAR-15 Commando
Marketing name used by Colt
XM177 (R610 in US Army service)
XM177E1 (R609 in US Army service)
XM177E2 (R629 in US Army service)
GAU-5/A (R609 in US Air Force service)
GAU-5A/A (R649 in US Air Force service)
Notable users
United States - US Army
United States - US Air Force



The Colt Commando is an early Cold War era compact assault rifle of US origin. In the mid 1960's Colt had developed the short barrel M16 SMG as part of its family of rifles centered around the M16A1. The Commando is a further development of the M16 SMG in order to make it simpler to produce and more reliable. The Commando is best known under the XM177 and GAU-5 designations used by the US Army and US Air Force respectively.


The Colt Commando is a very short variant of the M16A1 assault rifle. The dimensions and shorter effective range make more akin to a sub machine gun than an assault rifle. The Commando features a two position retractable stock. The Commando retains the direct impingement action and rotating bolt as used in the M16A1. The Commando is gas operated with a gas tube leading from near the end of the barrel down to a piston attached to the top of the bolt. The large flash hider also acts as a sound moderator.


The Commando fires the 5.56x45mm M193 round from 20 and 30 round magazines. The fire selector allows for semi-automatic and full automatic fire at a cyclic rate up to 950 rpm. The maximum effective range is over 200 m.


The Colt Commando was adopted in quite small numbers by the US Army and US Air Force for specialist use. It is famous for being used by Special Forces and Navy SEALs during the Vietnam war. Small numbers were exported to US allies in Asia and South America.


Colt Commando

US Navy SEALs with Colt Commando compact assault rifle in 1985.

Source: US Navy - © Public domain

Colt Commando

The first models of the Colt Commando featured a 10 inch barrel. The Commando differs from the earlier M16 SMG in having a simple two position retractable stock that wraps around the buffer tube at the rear of the receiver. It also features a round handguard instead of the triangular shape used on the M16A1.

In 1967, a year after the introduction of the first Colt Commando models, an updated model with 11.5 inch barrel was introduced. This was done to improve the reliability and the ability to mount the XM148 under barrel grenade launcher was introduced.

List of Colt Commando variants

Colt Commando R609
Colt Commando with 10 inch barrel and forward assist. Known as XM177E1 in US Army service.
Colt Commando R610
Colt Commando with 10 inch barrel but without forward assist. Known as the XM177 in US Army service and GAU-5/A in US Air Force service.
Colt Commando R629
Colt Commando with 11.5 inch barrel and forward assist. Known as XM177E2 in US Army service.
Colt Commando R649
Colt Commando with 11.5 inch barrel and no forward assist. Possibly the actual Colt index for this rifle is R630.


Facts Colt Commando R609 Colt Commando R629
United States
Assault rifle
5.56x45mm M193
20, 30 round detachable box
Barrel length
254 mm
6 grooves, right hand 305mm twist
Muzzle velocity
808 m/s
Gas operated, direct impingement, rotating bolt
Fire selector
0 - 1 -F
Rate of fire
700 - 900 rpm
Stock type
788 mm stock extended
719 mm stock retracted
2.15 kg empty
Iron sights, flip aperture

Related articles

Colt M16A1

The Colt Commando is part of the M16A1 family of rifles. These short barrel carbines uses the same operating mechanism and M193 series of 5.56mm ammunition.

Colt CAR-15

The CAR-15 bridges the gap between the Colt Commando and the M16A1. The CAR-15 has a longer 14.5 inch barrel than the Commando, but features the same retractable stock in order to reduce its dimensions.

Colt M4 Commando

The M4 Commando is a more modern iteration of the Colt Commando. It is based on the M16A2 platform and fires 5.56mm NATO ammunition.