ArmaLite M-15A4 in 5.56x45mm NATO with 16-inch barrel, representing ArmaLite's modern production AR-15 carrying the original manufacturer's lineage. Type: Rifle Action: Semi-Auto Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2000, USA Weight: 102 oz Overall length: 32.5" Status: Active Intended use: General purpose, home defense, patrol