8.6 Blackout Gains SAAMI Approval, But Twist Rate Confusion Remains

A new short-action cartridge from the creator of the 300 Blackout aims to do both subsonic and supersonic duty with more punch than its predecessor, and it just cleared SAAMI approval.

Snapshot

Richard Mann, writing for Shoot-On, breaks down the 8.6 Blackout, a Q LLC cartridge built from a shortened, necked-up 6.5 Creedmoor case that shares the .308 Winchester's rim diameter. He explains how its design and unusually fast twist rate are meant to improve on the 300 Blackout's terminal performance and range, while noting that SAAMI's standard specs don't match the cartridge's original intent.

Key points

• Lineage: Developed by Kevin Brittingham, the same designer behind the 300 AAC Blackout, the 8.6 Blackout is built on a case derived from the 6.5 Creedmoor.
• Dual performance: Supersonic loads push 185-grain bullets to about 2200 fps, while subsonic loads run heavier bullets (285 to 352 grains) for more energy than the 300 Blackout or 338 ARC offer.
• Twist rate complication: Q designed the cartridge around an extremely fast 1:3 twist for best bullet stability and terminal effect, but SAAMI's approved test barrel uses a slower 1:6 twist, meaning guns and ammo may not be optimized the same way.
• Bullet compatibility: According to Q engineer Nick Schafer, the 1:3 twist can strip jackets off some bullets, so shooters need to match ammunition to their barrel's twist rate carefully.
• Growing market: Wilson Combat, Just Cause Solutions, Fort Scott Munitions and Gorilla Ammunition are among the companies now offering 8.6 Blackout rifles and loads.

Quick take

For armed citizens and hunters tracking new chamberings, Mann's reporting flags a real tradeoff: the 8.6 Blackout offers more energy and reach than the 300 Blackout, but buyers need to understand twist rate before choosing a gun or ammo, since SAAMI's standard doesn't match the cartridge's original 1:3 design.

Read the full story: shoot-on.com