8.6 Blackout promises hunting power, but twist-rate confusion looms

Q Firearms, the company behind the 300 AAC Blackout, has developed a new short-action cartridge called the 8.6 Blackout, built around a shortened, necked-up 6.5 Creedmoor case, and Shoot-On's Richard Mann has put it through a detailed technical and field evaluation.

Snapshot

Mann explains that the 8.6 Blackout shares the .308 Winchester's rim diameter and was designed to improve on the .300 Blackout's terminal performance and range at both subsonic and supersonic speeds. He details its unusual 1:3 twist rate and its 2026 SAAMI approval, which complicates how the cartridge will actually be loaded and built going forward.

Key points

• Case design: Mann notes the cartridge necks a shortened 6.5 Creedmoor case up to 0.338-caliber, loaded to 62,000 psi max average pressure.
• Supersonic edge: He reports supersonic loads push 185-grain bullets to about 2200 fps from a 16-inch barrel, outpacing .300 Blackout and 338 ARC in energy.
• Subsonic advantage: According to Mann, factory subsonic loads run 285 to 352 grains, giving substantially more energy than comparable .300 Blackout or 338 ARC subsonic rounds.
• Twist rate complication: Mann and Q engineer Nick Schafer explain that the ideal 1:3 twist boosts bullet rotational speed and terminal upset, but SAAMI's approved spec uses a slower 1:6 test barrel, creating compatibility questions across ammo brands.
• Field use: Mann says he's hunting deer this season with a Q Fix SBR using Just Cause Solutions' 350-grain Maker RX subsonic load inside 75 yards.

Quick take

Mann makes clear the 8.6 Blackout offers real ballistic advantages over the .300 Blackout and 338 ARC, especially for hunters wanting flexible subsonic and supersonic performance from one rifle. But he's candid that SAAMI's approval path leaves twist-rate compatibility murky, meaning buyers need to pay close attention to barrel specs and ammo labeling before committing to a build.

Read the full story: shoot-on.com