Just exactly what is a 300 AAC Blackout?
Just exactly what is a 300 AAC Blackout? It’s a caliber that had its beginnings as the 300-221, a wildcat cartridge popularized by J.D. Jones of SSK Industries as the 300 Whisper®.
The cartridge is built on a 5.56×45 case shortened and necked to accept a 30-caliber bullet. When loaded with a 200 to 250-grain bullet the Whisper is subsonic; producing muzzle velocities of 960 feet per second from a 9” barrel to 1030 feet per second from a 16” barrel. There’s also a version loaded with a 125 grain projectile that achieves supersonic muzzle velocities of over 2200 feet per second in a 16 inch barrel.