The PWS MK109 is an 18-inch .308 Winchester long-stroke piston rifle in the AR-10 platform. The long-stroke piston system provides reliable operation with the higher-pressure .308 cartridge and is favored by users operating in adverse conditions. The MK109 ships with a PWS-designed muzzle device and adjustable gas system. It is one of the more expensive production .308 ARs but commands a loyal following among piston-platform enthusiasts. Type: Rifle Action: Semi-Automatic Caliber: 308 Winchester Capacity: 20 Year introduced: 2012, USA Weight: 120 oz Overall length: 38.5" Status: Active Intended use: Hunting, Long-Range Shooting, Precision Rifle