Adams Arms' P1 is the company's entry-level piston-driven AR-15, featuring the Adams Arms retrofit piston kit in a complete rifle package. The P1 was designed to bring piston reliability to the AR-15 at a mid-tier price point, appealing to military veterans familiar with piston-driven M16A2 variants. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2011, USA Weight: 108 oz Overall length: 33.5" Status: Active Intended use: Service, Law Enforcement, Home Defense