Ruger AR-556 Pistol in .300 Blackout with 9.45-inch barrel and SB Tactical pistol brace, Ruger's take on the compact .300 Blackout pistol market. Type: Pistol Action: Semi-Automatic Caliber: .300 Blackout Capacity: 30 Year introduced: 2019, USA Weight: 80 oz Overall length: 26.5" Status: Active Intended use: Suppressor Host, Home Defense