Colt M4 to M5 Carbine 5.56 X 45mm 16.1" Bbl Matte Black Conversion Kit CM556-16-CK

The Colt M4 to M5 Carbine Conversion Kit is a complete upper receiver assembly designed to upgrade any Colt M4-pattern lower to the next-generation M5 platform. It features a 16.1" chrome-lined M4 barrel with an A2 flash hider and a gas-block-mounted fixed front sight post with bayonet lug. The proven carbine-length direct gas system eliminates the conventional operating rod, reducing parts count and weight while accommodating the full range of 5.56mm ammunition — including NATO M855/SS109 and U.S. M193 — via a 1-in-7" right-hand twist barrel. The free-float rail and upper receiver system maximizes rail space and shooter comfort without sacrificing lethality or accuracy. The kit ships complete with the upper assembly, M4 Full Auto Bolt Carrier Assembly, charging handle, fixed post front sight, folding rear sight, and manual.