The 300 Blackout (300 BLK) was designed by Remington/AAC to create a reliable, compact .30 caliber round for the AR platform that uses a standard bolt and magazine. 300 Blackout is optimized for suppressed fire with heavy bullet subsonic loads but can also be used with supersonic ammunition when extra range is needed. The 1-8” twist will work well for subsonic and supersonic loadings alike and there is typically no need for an adjustable gas block when switching back and forth between the two loadings.