The M&P15 OR (Optics Ready) is a factory-configured AR-15 built specifically for optics use, shipping with a low-profile gas block allowing a free-float rail handguard and no iron sights installed. The flat-top upper provides a clean Picatinny rail for mounting any optic. Features a 16-inch barrel, 1:8 twist, and mid-length gas system. Designed for shooters who plan to mount an optic and do not need factory iron sights. Type: Rifle Action: Semi-Automatic Caliber: 5.56 NATO Capacity: 30 Year introduced: 2016, USA Weight: 6.4 oz Overall length: 35" Status: Discontinued Intended use: Sport Shooting, Tactical