The Adams Arms P2 is a short-stroke piston AR-15 built around Adams Arms' proprietary micro-sized piston system that fits into standard-dimension handguards without modification. The 16-inch barrel and carbine-length piston make it one of the most accessible piston ARs in terms of aftermarket handguard compatibility. Type: Semi-Auto Rifle Action: Short Stroke Piston Caliber: 5.56x45mm Capacity: 30 Year introduced: 2015, USA Weight: 6.9 oz Overall length: 32.5" Status: Active Intended use: Home Defense, Range, Duty