This Smith & Wesson AR-15 Stripped Lower Receiver is marked M&P 15 and utilizes .223 Remington / 5.56 NATO cal. If you have an AR-15 build planned, this lower is a great place to start. 6061-T6 Aluminum Lower. This lower is constructed of 6061-T6 Aluminum and features a black finish and an open trigger guard. This lower provides good bang for the buck and should present no problems using after market parts and all mil-spec parts to make a nice Mfg: Smith & Wesson
