A 12 inch barrel is the honest sweet spot for a suppressed 8.6 Blackout. The cartridge finishes its powder burn in roughly 8 inches, so the extra four inches buy stiffness and sight radius rather than velocity, and the whole rig stays shorter than a bare 20 inch hunting rifle once the can is mounted.
| Component | Specification |
|---|---|
| Chambering | 8.6 Blackout (8.6x43mm) |
| Barrel | 12 inches, 1:3 twist |
| Platform | AR-10 pattern, SR-25 magazines |
| Gas system | pistol length, adjustable block |
| Primary load | 342gr expanding subsonic, roughly 1,035 fps |
| Muzzle energy | roughly 815 ft lbs |
| Suppressed length | roughly 32 inches with a 7 inch can |
| Intended use | suppressed hog and deer inside 150 yards |
The 1:3 twist is the part not to compromise on. It spins a 342gr bullet past 250,000 rpm, which is what drives expanding and fracturing designs to open at subsonic speed instead of pencilling through. A slower twist barrel will still fire the ammunition and still be quiet, and it will quietly delete the reason you bought the cartridge.
Zero this build at 100 yards and hold for the drop past 150. Exact figures for your barrel and load are in the ballistics calculator, and the full reference tables sit in the 8.6 Blackout ballistics chart. Loads to feed it are on the 8.6 Blackout ammo shelf.
