The Adams Arms P1 Mid is a piston-driven AR-15 with a mid-length short-stroke gas piston operating system that keeps propellant fouling away from the bolt carrier group. Adams Arms is one of the most established piston conversion kit manufacturers in the AR-15 market and the P1 represents their complete rifle platform built around the piston system they developed for the AR-15 community. The piston system reduces carbon buildup on the bolt and reduces heat transfer to the shooter's hand during extended hog-hunting sessions. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm Capacity: 30 Year introduced: 2012, USA Weight: 105 oz Overall length: 32.5" Status: Active Intended use: hunting, hog_hunting, tactical