The Ruger AR-556 Multi-Purpose Rifle with 18-inch barrel, free-float M-LOK handguard, and Magpul MOE fixed stock. Designed for precision shooting at extended ranges with a longer sight radius and improved accuracy over 16-inch variants. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2017, USA Weight: 6.7 oz Overall length: 38.3" Status: Active Intended use: Hunting, Long Range, Range