Colt SMG

Colt SMG

Colt SMG

Colt SMG

The Colt 9mm SMG is blowback operated rather than the conventional direct impingement gas operation of the AR-15 series rifles, and it fires from a closed bolt.

The overall aesthetics are relatively similar to most AR-15 rifles. Changes include an enlarged brass deflector which replaces the standard AR-15 brass deflector. The magazine well of the receiver is modified using a special adaptor to allow the usage of smaller 9mm magazines. Factory Colt 9mm SMGs are equipped with a 10.5 inch length barrel and M16A1 style upper receiver. The magazines are a copy of the Israeli UZI SMG magazine with a modified locking slot to fit the AR-15's different magazine release button.

All Colt 9mm SMGs have an M16 style upper receiver, which means they feature a fixed carry handle with A1 sights and no forward assist. Current Colt production models are theRO635 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 latest version of the 635 is simply marked SMG 9mm NATO.