"Barnes Suppressor Series .308 Winchester 205 Grain Sierra GameKing Subsonic Rifle Ammo is optimized for use with suppressor-equipped hunting rifles. The Sierra GameKing projectile is designed to expand reliably even at subsonic velocities. If you're looking for great .308 subsonic ammo, you've found it. Note: Not optimized for cycling in semi-auto or full-auto platforms. It will fire from semi-auto and full-auto firearms, but will need to be cycled manually. Optimized for use with suppressors Clean-burning propellants to reduce buildup and fouling Sierra GameKing projectile with a jacketed lead core No supersonic ""crack"" when shooting"