The SL9 SD is a specialized variant of the HK433 platform chambered in .300 Blackout for the civilian market, optimized for suppressed use with subsonic ammunition. The integrally suppressed SD configuration provides very low noise signature with subsonic loads. Limited production for the European sporting market. Type: Semi-Auto Rifle Action: Short-Stroke Gas Piston Caliber: .300 Blackout Capacity: 30 Year introduced: 2018, Germany Weight: 9.2 oz Overall length: 34.65" Status: Active Intended use: Sport Shooting, Suppressor Host, Hunting