The One Horse 5.56 NATO Complete Upper Receiver is a purpose-built AR15 upper designed to deliver dependable accuracy, smooth cycling, and modular versatility. Built around a 16-inch 5.56 NATO barrel, this complete upper arrives fully assembled and ready to pin onto any Mil-Spec lower receiver. Whether you’re upgrading an existing rifle or completing a new build, this upper provides a reliable, work-ready foundation for range use, training, and defensive applications. Proudly made in the USA, it reflects a no-frills approach focused on performance and durability. What sets this One Horse upper apart is its balanced component selection and attention to real-world function. The free-float 15-inch handguard enhances accuracy by eliminating barrel contact while offering ample M-Lok real estate for lights, grips, and accessories. The included nitride bolt carrier group delivers smooth operation, excellent corrosion resistance, and reduced maintenance—ideal for high-round-count use. A full-length Picatinny top rail provides plenty of space for optics and iron sights, ensuring flexibility for a wide range of setups.

Specifications:

Manufacturer: One Horse

Platform: AR15

Caliber: 5.56 NATO

Barrel Length: 16 inches

Handguard: 15\" Free-Float M-Lok

Bolt Carrier Group: Nitride BCG (included)

Charging Handle: Included

Upper Rail: Full-length Picatinny

Compatibility: Mil-Spec AR15 lower receivers

Country of Manufacture: USA