Colt 9mm SMG

Colt M635


Colt R911

Left side view of Colt 9mm SMG with flat top receiver.
Source: - © Copyright lies with original owner

United States
Sub machine gun
Entered service
Mid 1980's
Limited service
1982 - 1984
United States - Colt
Mid 1980's - 2010's?
United States - Colt
Colt 9mm SMG
Notable users
United States - Law enforcement



The M635 is a late Cold War era sub machine gun of US origin. The name M635 refers to the most common variant of this sub machine gun. At a later stage this range of sub machine guns was marketed as the "Colt 9mm SMG". Development started in 1982 to compete with the MP5 as a sub machine gun for the American law enforcement market. The upside of the M635 is that manual of arms is fairly similar to the AR-15 platform, even though it uses a different operating mechanism. This comes at the drawback of shoehorning a rather basic blowback operating mechanism in place of the


The M635 is a simple blowback operated weapon, unlike the other weapons in the AR-15 family of rifles. Externally it looks similar to the Colt Commando in having a retractable stock, a lower receiver with regular size magazine well, and a short handguard with short barrel. Early production models have the distinctive carry handle with integrated rear sight and triangular front sight post. Modern variants feature a flattop upper receiver with Picatinny sight rail.


The M635 fires the 9x19mm Parabellum round from 20 or 32 round magazines. Cyclic rate of fire is very high at about 1.000 rpm. A hydraulic buffer exists that lowers rate of fire to 650 to 850 rpm. Law enforcement and civilian carbines are semi-automatic only. Since the M635 fires from a closed bolt it is easier to fire accurate shots than with an open bolt sub machine gun. Effective range is about 100 meters.


The M635 was acquired by various local and national law enforcement agencies in the USA. It was also exported and is most popular in South America. Many versions have been produced and even within a designation over time various small features have changed. It is still marketed today as the Colt 9mm SMG.


Colt R635

R635 = 0-1-F, retractable, 10.5 inch R639 = 0-1-3, retractable, 10.5 inch HB suffix = hydraulic buffer for lower 650 to 850 rpm cyclic rate

Colt R991

The R991 is an updated variant of the R635. It has a flattop receiver fitted with a Picatinny rail for mounting optical sights. It has a 0-1-F trigger group and a 10.5 inch barrel. A quad rail handguard is optional. The R992 is similar but features a 0-1-3 trigger group.

Colt R633 "briefcase model"

The R633 is the most compact variant in the 9mm SMG family. Reportedly it was developed of the US Department of Energy. It is also known as the briefcase model. A short 7 inch barrel is fitted and a hand stop doubles as front sight post. There is no muzzle device.

Colt "DEA model"

The so-called DEA model is a R635 or R639 rebuilt with an integral suppressor by Knight's Armament Company. More than one type of suppressor configuration exists.

Colt R6430

R6430 = civilian semi-auto carbine with fixed stock and 16 inch barrel, Colt Sporter Lightweight model R6450 = civilian semi-auto carbine with retractable stock and 16 inch barrel MT6430 = Match Target Lightweight, 16 inch, fixed handle sights

Colt AR6460

AR6460 = law enforcement semi-auto carbine with retractable stock and 16 inch long barrel and bayonet lug AR6951 = law enforcement flattop semi-auto carbine with retractable stock and 16 inch long barrel and bayonet lug


Facts Colt M635
United States
Sub machine gun
9x19mm Parabellum
Feed system
20 or 32 round detachable box magazine
Barrel length
267 mm
254 mm, right hand twist
Muzzle velocity
About 400 m/s
Blowback operated, fires from closed bolt
Fire selector
0 - 1 - F
Rate of fire
1.000 rpm
Stock type
Retractable stock
0.73 m stock extended
0.65 m stock retracted
2.6 kg empty
Post front and two position flip-aperture rear
Range adjustment
50 or 100 m
Sight radius

Related articles

Heckler & Koch MP5

The Colt 9mm SMG was developed to compete with the MP5 in the American law enforcement market.

Colt Commando

The Colt 9mm SMG looks very similar to the Colt Commando, especially when no magazine is fitted.