The 8.6 Blackout, also known as 8.6 BLK, is a relatively new cartridge designed for use in a variety of firearms, including AR-10 platforms. It is developed by the firearm company Q, headed by Kevin Brittingham, who also developed the popular .300 AAC Blackout. The 8.6 Blackout uses a necked-up .308 Winchester case to accommodate an 8.6 mm (approximately .338 inch) bullet.
Designed with modern shooting requirements in mind, the 8.6 Blackout is optimized for subsonic performance, making it suitable for use with suppressors. This makes it particularly appealing for hunters and tactical shooters seeking a quiet but powerful round. The cartridge can also be used in supersonic configurations, offering versatility for different shooting scenarios.
The intended uses of the 8.6 Blackout are diverse and include hunting medium to large game, tactical operations, and recreational shooting. Its ability to deliver high energy at subsonic speeds sets it apart, combining effective terminal ballistics with reduced noise levels.