A completely re-engineered line of modern sporting rifles representing the latest evolution in AR-pattern firearms. Nitrided bolt and bolt carrier group feature a staked gas key. Magpul M-LOK accessory attachment slots at the 3:00, 6:00, and 9:00 positions, with 8 intermediate slots at the muzzle end. Threaded barrel features a 1/2X28 muzzle thread and is fitted with an A2 flash hider. Upper and lower receivers are machined to mil-spec dimensions from 7075 forgings and Type III hard coat anodized. Lower receiver includes a tension screw to eliminate play between the upper and lower receivers.