BCG Optional, Phosphate or Chrome no cost difference.1:8 twist rate, will shoot anything you can buy, including Tracers.5 Different Muzzle Devices to choose from, no cost difference.Muzzle Device is not pinned, easily removable.Three different Upper Receiver styles to choose from (Slick Side, M16A1 or C7).Production ran only about one year (1966-67), with possibly less than 3,000 fielded before replacement in 1967 by the longer (and better known) 11.5 inch XM177E2.Īir Force version (model 610) ran concurrently with Army models feature for feature, but did not have a Forward Assist ('Slick Sides').
The 10 inch barrel Colt XM177 (model 609) was essentially a fielded prototype - and the first Colt CAR-15 SMG version to see limited issue to SEALs, Special Forces and the CIA.
