Phantom Defense 8.6 Blackout 300gr Sierra Match King HPBT Subsonic Rifle Ammo - 20 Rounds - 8.6 Blackout 300 gr subsonic Sierra Match King Hollow Point Boat Tail rounds in new Starline brass. This round is in our product lineup in an effort to bring you 8.6 Blackout ammo at an economical price point. The 8.6 Blackout (8.6 BLK) is the next evolution in high-performance ammunition, designed by Kevin Brittingham and his team at Q LLC. Building on the success of the .300 Blackout, the 8.6 BLK was developed to provide superior energy, range, and versatility, especially for AR-10 platforms. This groundbreaking cartridge applies the design principles of the .300 BLK to a larger, .338-caliber bullet, offering dramatically enhanced performance while maintaining compatibility with .308-sized platforms. A simple barrel swap is all that's required to convert AR-10s and .308 Winchester bolt guns to 8.6 BLK, making the transition seamless. What sets the 8.6 BLK apart is its ability to fire a wide range of bullet weights, from 160 to 210 grains at supersonic speeds, and 280 to 350 grains at subsonic velocities. The cartridge excels in short-barrel rifles and is highly effective in suppressed applications, making it ideal for hunters and tactical shooters alike. The supersonic rounds deliver up to 2,400 feet per second and impressive energy transfer, while the heavy subsonic bullets deliver tremendous stopping power, with energy exceeding 830 ft-lbs.