What is 8.6 Blackout?
8.6 Blackout is a .338-caliber (8.6mm) cartridge developed by the same team behind the wildly popular .300 Blackout. It was designed from the ground up for one job: delivering devastating terminal performance from short, suppressed barrels — both subsonic and supersonic. Think of it as the big brother to .300 Blackout, built around a shortened 6.5 Creedmoor-based case so it feeds from AR-10/SR-25-pattern magazines and short-action bolt guns.
The 1:3 twist rate — why it matters
The defining feature of 8.6 Blackout is its extremely fast 1:3 inch twist rate. Most rifle cartridges use twist rates between 1:8 and 1:12. By spinning the heavy .338 projectile far faster, 8.6 Blackout generates enormous rotational energy. Even at subsonic velocities, that spin drives dramatic expansion and fragmentation on impact — the kind of terminal effect that subsonic rounds traditionally struggle to produce.
Subsonic vs. supersonic 8.6 Blackout
- Subsonic (typically 285–342gr): Quiet, suppressor-friendly, and ideal for close-to-mid-range hunting where noise matters. The fast twist makes subsonic loads hit far harder than the bullet weight alone suggests.
- Supersonic (lighter projectiles): Flatter trajectory and more energy at distance for open-country hunting and target work.
What is 8.6 Blackout good for?
8.6 Blackout shines for suppressed hog and deer hunting, predator control, and any scenario where a hunter wants heavy-bullet terminal performance with minimal noise and a compact rifle. Its short overall length and AR-10 compatibility make it a natural fit for suppressed truck guns and brush rifles.
8.6 Blackout vs. .300 Blackout
.300 Blackout uses a .30-caliber bullet on a 5.56-based case and runs in AR-15s. 8.6 Blackout uses a larger .338 bullet on a 6.5 Creedmoor-based case and runs in AR-10s. In short: 8.6 Blackout carries more bullet weight and energy for larger game, while .300 Blackout remains the lighter, more compact option for the AR-15 platform.
Rifles and platforms
8.6 Blackout runs in AR-10/SR-25-pattern semi-autos and purpose-built bolt actions. Because of the heavy bullets and fast twist, it is best paired with a quality suppressor and a barrel cut specifically for the cartridge.
Shop 8.6 Blackout
Browse our full lineup of 8.6 Blackout ammunition, including subsonic loads and bulk buckets.
8.6 Blackout FAQ
Is 8.6 Blackout subsonic or supersonic? Both — it is offered in subsonic and supersonic loadings.
What twist rate does 8.6 Blackout use? A very fast 1:3 inch twist.
Can I shoot 8.6 Blackout in an AR-15? No. It is built on a 6.5 Creedmoor-based case and runs in AR-10/SR-25-pattern rifles, not AR-15s.
Is 8.6 Blackout good for deer and hogs? Yes — heavy .338 bullets and the fast twist make it an excellent suppressed hunting cartridge for medium and large game.