Sons of Liberty Gun Works M4-L89 Upper Receiver Group Features The Sons of Liberty Gun Works M4-L89 Upper Receiver Group is built around a Liberty Fighting Barrel a component the company designs and manufactures specifically for consistent accuracy and reliable function under hard use. The 14.5 threaded barrel is chambered in 5.56 NATO giving builders a compact maneuverable profile suited to close-quarters and general-purpose applications alike. A forged upper receiver provides the strength and durability expected of a mil-spec-pattern AR-15 build standing up to years of hard training and range use. The matte black finish resists wear and corrosion keeping the upper looking clean through repeated cleanings and rough handling. The included 13.75 L89 seven-sided rail gives shooters a slim lightweight handguard with plenty of real estate for lights lasers and other accessories in whatever configuration the build calls for. Its forend design keeps the profile close to the barrel for a natural ergonomic grip during rapid target transitions. This upper is sold without a bolt carrier group or charging handle letting builders select their preferred components for the rest of the rifle. For AR-15 owners who want a proven purpose-built barrel and rail combination from a respected manufacturer this upper receiver group offers a strong foundation for a dependable rifle build. Sons Of Liberty Gun Works M4-L89 Upper Receiver Group Specifications Manufacturer: Sons of Liberty Gun Works Model: M4-L89 Upper Receiver Group Caliber: 5.56 NATO Barrel Length: 14.5 Barrel Type: Threaded Compatible Hosts: AR-15 Handguard: 13.75 L89 Rail Finish: Matte Color: Black Available At: GrabAGun