If you're looking to build something on an AR15 platform and want the absolute best semiautomatic tactical rifle upper, consider building around this POF-USA Minuteman upper. The Patriot Ordnance Factory Minuteman provides the end user with some of the most impressive innovations in the industry, from the 4150 nitride-treated steel barrel with three-pronged flash hider to the Strike Eagle ambidextrous charging handle that is built for speed & comfort. This complete Minuteman 16.5" upper receiver assembly is chambered for 5.56x45mm Nato, E Squared chamber and utilizes semiautomatic direct impingement technology. It features a Renegade rail that's M-LOK compatible. It also has four integrated quick-detach sling mounts. This MILSPEC upper receiver will make your build something special.