8.6 Blackout ammo comes in two kinds: subsonic loads with heavy 300 to 352 gr .338 bullets at about 1,000 fps for suppressed shooting, and supersonic loads with lighter bullets around 180 to 200 gr. Factory 8.6 Blackout ammo is made by specialty makers such as Just Cause USA and Black Butterfly Ammunition. Match the load to your twist rate. Chattahoochee Munitions manufactures the CM7S bolt action and CM10 AR10 firearms to fire it.
8.6 Blackout Ammo at a Glance
| Load | Type | Published velocity | Maker |
|---|---|---|---|
| 350 gr Maker REX rapid expanding | Subsonic, hunting | 950 fps (8 inch), 980 fps (12 inch), 1,040 fps (16 inch) | Just Cause USA |
| 352 gr Maker REX | Subsonic, hunting | Not listed | Just Cause USA |
| 300 gr Maker solid | Non-expanding | Not listed | Just Cause USA |
| 180 gr Maker T-REX | Supersonic, hunting | Not listed | Just Cause USA |
| 352 gr Maker Buzz Saw | Subsonic, hunting; bolt action and AR10 versions | About 1,000 fps (12.5 inch, 1:3) | Black Butterfly Ammunition |
| 305 gr Maximus Fractura | Subsonic, fracturing; bolt action and AR10 versions | About 1,000 fps (12.5 inch, 1:3) | Black Butterfly Ammunition |
Velocities and descriptions are as published by each maker. Black Butterfly lists its figures as tested in a Chattahoochee Munitions firearm with a 12.5-inch, 1:3 barrel. Availability changes often; check each maker’s site. Chattahoochee Munitions does not load 8.6 Blackout ammunition and publishes no load data.
Subsonic or Supersonic 8.6 Blackout Ammo?
Subsonic 8.6 Blackout ammo is the main reason people choose the cartridge. Bullets stay below the speed of sound, about 1,116 fps at 59°F, so there is no supersonic crack and a suppressor only has to handle muzzle blast. Heavy 300 to 352 gr bullets keep roughly 680 to 840 ft-lb at that speed. Supersonic 8.6 Blackout ammo gives a flatter path and more energy for longer shots; SAAMI’s reference load is a 200 gr bullet at 2,200 fps, about 2,150 ft-lb. See 8.6 Blackout ballistics.
How Do I Match 8.6 Blackout Ammo to My Twist Rate?
Start with bullet weight. With barrels of about 12.5 inches or longer, Chattahoochee Munitions testing has generally favored:
- 1:3 for heavy subsonic bullets of about 323 gr and up, such as the 350 and 352 gr Maker REX and the 352 gr Buzz Saw.
- 1:5 for bullets of about 300 gr and under, and for supersonic loads.
Ammunition makers also publish their own guidance. Just Cause USA lists a 1:3 to 1:6 range for its 350 gr load, and Black Butterfly lists 1:3 for its 305 and 352 gr loads. When the maker’s guidance and your barrel disagree, confirm on target before you hunt. See 8.6 Blackout twist rate.
Is There Separate 8.6 Blackout Ammo for Bolt Actions and AR10s?
Some makers offer it. Black Butterfly sells its 305 and 352 gr subsonic loads in separate versions for bolt actions and for AR10 platforms. Use the version made for your firearm. Both the CM7S and CM10 feed from magazines that Chattahoochee Munitions vets with 8.6 Blackout: the CM7S 10-round AICS-pattern magazine and the CM10 10-round SR25-pattern magazine.
Which 8.6 Blackout Ammo for Hunting?
Use an expanding or fracturing bullet: the Maker REX, Maker Buzz Saw or Maximus Fractura loads. Black Butterfly states its Maximus Fractura needs at least 800 fps at impact to work as designed. Solid non-expanding bullets are for targets, not game. Bullets from Maker Bullets appear in several of these loads. See 8.6 Blackout hunting.
8.6 Blackout Ammo Safety
- Fire 8.6 Blackout ammo only in a firearm marked 8.6 Blackout or 8.6 BLK.
- Keep 8.6 Blackout and 300 Blackout ammunition apart; both say “Blackout” on the box.
- Black Butterfly advises against chambering the same round repeatedly; inspect or retire rounds that have been chambered many times.
- Wear hearing protection even with subsonic ammunition and a suppressor; see the NIOSH noise guidance.
Which Firearm for Your 8.6 Blackout Ammo?
For heavy subsonic loads in a short, suppressed firearm, the CM7S 8.6 Blackout short barreled rifle or the CM10 8.6 Blackout SBR. For subsonic and supersonic use without SBR paperwork, the CM7S 8.6 Blackout bolt action rifle or the CM10 8.6 Blackout semi auto rifle. Every firearm is offered with a 1:3 or 1:5 twist; see them all in Area 8.6, and read What Is 8.6 Blackout?
8.6 Blackout Ammo FAQ
Who makes 8.6 Blackout ammo?
Specialty makers including Just Cause USA and Black Butterfly Ammunition, with bullets from Maker Bullets and others.
What bullet weight is 8.6 Blackout subsonic ammo?
Factory subsonic loads use about 300 to 352 gr bullets, with 350 and 352 gr expanding bullets for hunting.
What twist do I need for 350 gr 8.6 Blackout ammo?
With barrels of about 12.5 inches or longer, Chattahoochee Munitions testing has generally favored 1:3 for bullets of about 323 gr and up.
Is 8.6 Blackout ammo subsonic?
Most of it is, at about 1,000 fps. Supersonic loads with lighter bullets are also made.
Can I shoot 8.6 Blackout ammo in a 300 Blackout?
No. They are different cartridges. Fire only the cartridge marked on your firearm.
Does Chattahoochee Munitions sell 8.6 Blackout ammo?
No. Chattahoochee Munitions manufactures 8.6 Blackout firearms, barreled actions and magazines.
Who makes 8.6 Blackout rifles for this ammo?
Chattahoochee Munitions manufactures the CM7S bolt action at 8, 12.5 and 16 inches and the CM10 AR10 at 8, 12.5 and 16 inches, each with a 1:3 or 1:5 twist Mos-Tek barrel.