The American Tactical ALPHA MAXX AR-15 features the new Gen 2 Alpha Maxx Receiver with an upgraded combination of carbon fiber, steel, and polymers resulting in ATI's strongest and most durable receiver to date. This Alpha Maxx model features a fully-patented metal reinforced polymer upper and Gen 2 lower receiver group. The Alpha Maxx lower features a patented hammer and trigger pin retainment system which prevents movement from the hammer and trigger pin during firing. It also features ATIs patented over-molded metal insert, which reinforces the buffer tube housing and rear takedown pin. This allows for metal-on-metal contact with both the buffer tube as well as the rear takedown pin, thus increasing strength and durability from recoil and consistent firing. This model also features a 16" black nitride barrel and a 13" M-Lok rail.