The Colt 9mm SMG is a 9x19mm Parabellum submachine gun manufactured by Colt, based on the M16 rifle platform.
The Colt 9mm SMG is a closed bolt, blowback operated SMG, rather than the conventional direct impingement gas operation of the standard 5.56x45mm M16 type rifle.
The overall aesthetics are identical to most M16 type rifles. Changes include a large plastic brass deflector mounted toward the rear of the ejection port. Factory Colt 9mm SMGs are equipped with a 10.5 inch length barrel and have an M16 style upper receiver, which means they feature a fixed carry handle, no forward assist and A1 sights (with 50 and 100 meter settings). The magazine well of the receiver is modified using a special adapter to allow the usage of smaller 9mm magazines. The magazines themselves are a copy of the Israeli UZI SMG magazine, modified to fit the Colt and lock the bolt back after the last shot.
Current Colt production models are the RO635 which features a Safe/Semi/Full Auto selective fire trigger group and the RO639 which features a Safe/Semi/3 round Burst selective fire trigger group. Both are equipped with a 10.5 inch length barrel. The 633 was a modified compact version with a 7 inches (180 mm) barrel and simplified front sight post used by the DEA.
The most common model is the 635, the latest version of which are simply marked SMG 9mm NATO.
Weight 2.61 kg (5.75 lb) w/o magazine
Length 28.9 in (stock extended), 25.6 in (stock retracted)
Barrel length 10.5 in
Cartridge 9x19mm Parabellum
Action blowback, closed bolt
Rate of fire 700-1000 round/min
Muzzle velocity 396 m/s (1300) ft/s)
Effective range 100 m
Feed system 32 round detachable box magazine