The Aero Precision M4E1 pistol with 10.5-inch barrel is a compact AR pistol for home defense and suppressor use. The pistol-length gas system and 10.5-inch barrel deliver reliable cycling with standard 5.56 NATO ammunition. The M4E1 enhanced lower accommodates a pistol brace in the standard configuration. Ships with an Aero ATLAS handguard. Type: Pistol Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2017, USA Weight: 56 oz Overall length: 26.5" Status: Active Intended use: Home Defense, Suppressor Host, Duty Use