The Colt 9mm SMG, also known as Colt Model 635, is a 9x19mm Parabellum submachine gun based on the M16. Manufactured by Colt beginning in 1982, this firearm is closed bolt and blowback operated giving the Colt 9mm SMG more accuracy compared to open bolt weapons such as the Uzi. Almost identical in look to the M16, the Colt SMG uses an M16 style upper receiver and retained M16-style fire controls.