The Colt Machine Gun-1 or CMG-1 was an open bolt belt-fed machine gun that fired 5.56x45mm cartridges designed by Colt Manufacturing Company in 1965. Colt hastily developed the CMG-1 to complement the CAR-15, a Colt branding of the M16 rifle, so that Colt might offer both of them as an alternative to the Stoner 63 weapons system. It failed to achieve any sales, and was replaced by the Colt CMG-2, which also failed to achieve any sales.