The LWRC IC-PSD (Personal Security Detail) is a piston-operated pistol-configuration AR-15 with an 8.5-inch barrel and SB Tactical brace. The piston system is particularly advantageous in short-barrel configurations where DI creates excessive pressure and carbon fouling. Type: Semi-Auto Pistol Action: Piston-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2013, USA Weight: 6.1 oz Overall length: 24.5" Status: Active Intended use: Home Defense, Patrol, Tactical