8.6mm Blackout (8.6×43 mm), sometimes referred to as 8.6 BLK, is a centerfire rifle cartridge developed by the firearms manufacturer . It utilizes a shortened case from the 6.5mm Creedmoor necked up to an 8.6mm caliber (8.585mm or 0.338in diameter) projectile. 8.6 Blackout is designed for use in bolt-action rifles or as a caliber conversion for AR-10 style rifles.

The only required modification to convert an existing .308 Winchester-chambered rifle to 8.6mm Blackout is the replacement of the barrel. The 8.6 Blackout shares the same case head and bolt diameter as its parent cartridge, 6.5mm Creedmoor. All other components of a standard AR-10 rifle are compatible. Modifications to the operating system such as the buffer, buffer spring and gas system may be made in order to optimize functionality of the firearm. 8.6 Blackout fits in standard, unmodified .308 Winchester or 6.5 Creedmoor magazines with no effect on capacity.

The 8.6 Blackout is designed for barrels using a 76mm or 102mm (1:3 in or 1:4 in) twist rate and bullet weights between 10.4–14.6g (160–225gr) for supersonic loads and 18.5–22.7g (285–350gr) for subsonic loads. The "fast" twist rate 8.6mm Blackout was intended to create better expansion and more terminal energy transferred to the target through the "blender effect" of a rapidly-spinning subsonic bullet.

Platforms

ManufacturerModelTypeCountry
QFixBolt action rifleUnited States
QBoomboxSemi-automatic rifleUnited States
Chattahoochee MunitionsCM7SBolt action rifle and pistolUnited States
Chattahoochee MunitionsCM10Semi-automatic rifle and pistolUnited States
Faxon FirearmsSentinelSemi-automatic rifleUnited States
Gorilla AmmunitionGF-10Semi-automatic rifleUnited States
Bear Creek ArsenalBC-10Semi-automatic rifleUnited States
RossiLWCSingle shot rifleUnited States
Robinson ArmamentXCR-M (Mini & Mid)Semi-automatic rifleUnited States

See also