Colt Colt M4 to M5 Carbine Upper Reciever Kit 5.56 Nato 16.1 in. Heavy Barrel Black CM556-16-CK

The Colt M4 to M5 Carbine Upper Receiver Kit is a complete 5.56 NATO upper receiver assembly designed to modernize legacy M4 platforms. It features a 16.1-inch chrome-lined heavy barrel, a one-piece free-floating M-LOK handguard, and a continuous MIL-STD-1913 top rail for mounting optics and accessories. The M5 upper incorporates an improved barrel retention interface with a self-centering barrel nut and keyed barrel extension for enhanced rigidity and accuracy. The kit includes an ambidextrous Radian Raptor charging handle and Troy folding metal sights. Complete upper receiver assembly;Chambered in 5.56 NATO;16.1" chrome-lined heavy barrel;One-piece free-floating M-LOK handguard;Continuous MIL-STD-1913 top rail;Improved barrel retention interface with self-centering barrel nut and keyed barrel extension;Free-float barrel system for increased rigidity and accuracy;Includes: Ambidextrous Radian Raptor charging handle, Troy folding metal front sight, Troy folding metal rear sight;Colt low-profile pinned gas block;Carbine-length direct impingement gas system;HP/MPI tested bolt carrier group with chrome-lined carrier and properly staked gas key;Compatible with legacy M4 lower receivers