The PDS (Piston Driven System) Pistol was RRA's AR pistol built around a short-stroke piston system — an unusual choice for an AR pistol at a time when most were DI. The 8-inch barrel and piston drive were designed to run more reliably suppressed, and the pistol configuration avoided NFA restrictions. Type: Pistol Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2008, United States Weight: 80 oz Overall length: 22" Status: Active Intended use: Recreational Shooting, Home Defense