The Colt complete upper receivers bring the legendary reliability of the Colt name to your rifle or build with a ready-to-fire 5.56 mm NATO platform, featuring a Black finish and a 16-inch M4-style upper that pairs seamlessly with standard AR-15 lower receivers. This Colt upper includes a robust upper receiver assembly designed for dependable performance, optimized handguard interface, and built-in compatibility with Matech BUIS to enhance field versatility without compromising a clean, streamlined profile. The combination of a conventional government-profile barrel and Colts precision-machined components delivers consistent accuracy and repeatable cycling, making it an ideal foundation for duty, sport, or recreational use. Whether youre upgrading an existing configuration or assembling a new rifle from the ground up, this complete upper offers a straightforward path to a reliable platform capable of handling 5.56 NATO ammunition with confidence. With Colts heritage of durability and thoughtful engineering, you gain a ready-to-install upper that supports quick installation, smooth ejection, and steady performance in a variety of shooting scenarios, from target work to practical field applications.