Ruger AR-556 in 6.8 SPC with 18-inch barrel, an accessible direct-impingement AR-15 offering in the SOCOM-developed intermediate cartridge. Type: Rifle Action: Semi-Automatic Caliber: 6.8 SPC Capacity: 26 Year introduced: 2016, USA Weight: 96 oz Overall length: 35.5" Status: Active Intended use: Hunting, Sporting