The Colt LE6921CK M4 upper group is a .223 Remington/5.56 NATO complete upper receiver with a 14.5-inch barrel. This complete upper is ready to mount to a complete lower receiver and includes a charging handle and a complete bolt carrier group with a properly head-spaced bolt, featuring a chrome-lined bolt carrier and barrel with 1/7 right hand twist barrel rifling.
This upper assembly features a gas-block mounted fixed front sight post with bayonet lug and a flip-up backup rear sight, with Colt’s standard 14.5″ chrome lined M4 barrel and an A2 flash hider up front. The upper receiver allows for a free-floated barrel with an uninterrupted full-length front rail, delivering enhanced accuracy and modularity for AR platform builds.
Equipped with an M4 contour 14.5″ barrel, carbine length polymer handguards, and convenient F-marked front sight, this factory-original Colt component integrates seamlessly with standard AR-15 lower receivers. Whether you’re building a tactical rifle or upgrading an existing platform, the LE6921CK delivers the reliability Colt has been known for since 1836.
