375 Raptor vs 8.6 Blackout compares two large-bore cartridges from the .308 Winchester family, and both are made for short-barrel subsonic shooting behind a suppressor. The short answer: the 375 Raptor, designed by Arne Brennan, fires a heavier, wider bullet (400 grains at .375 inch in Chattahoochee Munitions subsonic ammunition) and also carries a true supersonic hunting load, while the 8.6 Blackout fires .338-caliber bullets, is SAAMI standardized, and goes down to an 8-inch barrel. Chattahoochee Munitions manufactures complete CM7S bolt action and CM10 semi-automatic firearms in both cartridges, so this comparison comes from the same factory, the same actions, and the same suppressor testing.
375 Raptor vs 8.6 Blackout at a Glance
| Feature | 375 Raptor | 8.6 Blackout |
|---|---|---|
| Bullet diameter | .375 inch | .338 inch |
| Case family | .308 Winchester, necked up to .375 | .308 Winchester family, derived from the 6.5 Creedmoor case and necked up to .338 |
| SAAMI status | No SAAMI specification published | SAAMI standardized |
| Heavy subsonic bullet | 400 gr Maker REX (Chattahoochee Munitions load) | Roughly 300 to 330+ gr |
| Supersonic load | 190 gr Maker T-REX, 2,450 fps, 2,533 ft-lb (16-inch bolt action) | Lighter bullets, about 300 gr and under |
| Chattahoochee Munitions twist | 1:8 | 1:3 or 1:5 |
| Chattahoochee Munitions barrel lengths | 12.5 and 16 inch | 8, 12, 12.5, and 16 inch |
| CM10 semi-automatic | Centerfeed system with modified MDT metal magazine | Conventional AR10 architecture with customized feed ramps |
| CM7S bolt action | Yes, including PLACID OTB integrally suppressed models | Yes |
| Chattahoochee Munitions ammunition | Yes: subsonic and supersonic, loaded separately for bolt action and semi-auto | Not currently offered |
Watch: 375 Raptor vs 8.6 Blackout
Desk Pop filmed a 375 Raptor vs 8.6 Blackout comparison using a Chattahoochee Munitions 375 Raptor rifle.
375 Raptor vs 8.6 Blackout: Which Hits Harder Subsonic?
The 375 Raptor carries more energy at subsonic speed because it fires a heavier bullet. Below the speed of sound, both cartridges are limited to roughly the same velocity, so bullet weight decides the energy. Chattahoochee Munitions’ 400 gr Maker REX subsonic load averages 1,012 fps from a 12.5-inch barrel, about 910 ft-lb at the muzzle. At the same velocity, that is roughly 20 to 35 percent more energy than a 300 to 330 gr 8.6 Blackout bullet, and the .375-inch bullet starts wider before it expands.
The Maker REX is a solid copper expanding projectile. Maker Bullets designs it to open well at subsonic impact velocity, which is what makes a heavy subsonic bullet a hunting bullet rather than only a range bullet.
375 Raptor vs 8.6 Blackout in a Short Barrel
Both cartridges are made for short barrels, and short-barrel subsonic shooting is where Chattahoochee Munitions focuses. A subsonic load does not need a long barrel to reach full velocity, so a 12 to 12.5-inch barrel keeps the suppressed firearm compact without giving up performance.
- Choose 8.6 Blackout when overall length matters most. Chattahoochee Munitions offers 8.6 Blackout down to 8 inches in both the CM7S and CM10.
- Choose 375 Raptor when bullet weight matters most. The 12.5-inch CM7S and CM10 375 Raptor SBRs put the 400 gr subsonic load in a compact host, and the 16-inch rifles add the full supersonic load for longer shots.
For barrel length and twist choices in 8.6 Blackout, see the 8.6 Blackout subsonic guide.
375 Raptor vs 8.6 Blackout Supersonic Performance
Arne Brennan’s 375 Raptor is the stronger supersonic cartridge of the two. Chattahoochee Munitions loads a 190 gr Maker T-REX supersonic bullet at an average of 2,450 fps from a 16-inch bolt action barrel, 2,533 ft-lb at the muzzle. That gives a 375 Raptor owner a true supersonic hunting load and a heavy subsonic load in the same rifle. The 8.6 Blackout also fires lighter supersonic bullets, but most shooters choose it for subsonic use.
375 Raptor vs 8.6 Blackout Twist Rate: 1:8 vs 1:3 and 1:5
A subsonic bullet spins slowly because it travels slowly, so heavy subsonic bullets need a fast twist to stay stable. The 8.6 Blackout relies on extreme twist rates; Chattahoochee Munitions offers 1:3 for heavy subsonic bullets of about 323 grains and up, and 1:5 for bullets of about 300 grains and under. The 375 Raptor’s wider bullet needs less twist for the same job. Chattahoochee Munitions 375 Raptor barrels, made by Mos-Tek from 416R stainless steel with 5R rifling and finished in E100 Blackout Cerakote, use a 1:8 twist, well inside Maker Bullets’ guidance of 1:11 or faster for the 400 gr REX.
Bolt Action or Semi-Automatic?
Both cartridges run in the CM7S bolt action and the CM10 semi-automatic, but the CM10s are not the same. The CM10 8.6 Blackout uses conventional AR10 architecture with customized feed ramps. The CM10 375 Raptor uses a centerfeed system and a modified MDT metal magazine, because the long 400 gr subsonic cartridge (2.790 inches overall) needs a different feeding geometry. Both CM10s use a Superlative Arms adjustable gas block and an Odin Works adjustable AR10 buffer so one rifle can run subsonic and supersonic loads.
In either cartridge, a manually operated bolt action releases no gas through the action when it fires. With 375 Raptor, Chattahoochee Munitions also loads bolt action and semi-automatic ammunition separately, so each load is optimized for its platform.
Suppressors for 375 Raptor and 8.6 Blackout
Both cartridges are made to be shot suppressed. The PLACID 375 is rated from 5.56 NATO through .375 caliber, so one suppressor covers both cartridges. On the 12.5-inch CM7S 375 Raptor, the PLACID OTB over-the-barrel system wraps much of the suppressor around the barrel to keep the rifle short.
For subsonic ammunition, an enclosed suppressor is recommended on both the CM7S bolt action and the CM10 semi-automatic. For supersonic ammunition, the CM7S stays with an enclosed suppressor, while a flow-through suppressor is recommended on the CM10. The 375 Raptor suppressor guide covers the choice in detail.
375 Raptor vs 8.6 Blackout Ammunition
Chattahoochee Munitions manufactures loaded 375 Raptor ammunition with Maker Bullets projectiles in converted .358 Winchester brass: the 400 gr Maker REX subsonic for bolt action, the 400 gr Maker REX subsonic for semi-auto, and 190 gr Maker T-REX supersonic loads for each platform. Because there is no SAAMI specification for 375 Raptor, buy ammunition loaded for 375 Raptor and for your platform. The 8.6 Blackout’s SAAMI standardization means more commercial ammunition is made to one published standard.
375 Raptor vs 8.6 Blackout: Which Should You Choose?
- Choose 375 Raptor for the heaviest subsonic bullet, a true supersonic hunting load in the same rifle, and factory ammunition from the same company that manufactures the firearm.
- Choose 8.6 Blackout for the shortest possible host, an 8-inch barrel, and a SAAMI-standardized cartridge.
Browse the complete 375 Raptor lineup in the Raptor Paddock, including the 12.5-inch CM7S 375 Raptor, the 12.5-inch CM10 375 Raptor SBR, and the CM7S 375 Raptor with PLACID OTB. For 8.6 Blackout, visit Area 8.6.
375 Raptor vs 8.6 Blackout FAQ
Who makes 375 Raptor and 8.6 Blackout rifles?
Chattahoochee Munitions manufactures complete factory firearms in both cartridges: CM7S bolt action rifles, SBRs, and pistols, and CM10 semi-automatic rifles and SBRs. For 375 Raptor that means 12.5 and 16-inch barrels, including PLACID OTB integrally suppressed CM7S models; for 8.6 Blackout, 8, 12, 12.5, and 16-inch barrels.
Is 375 Raptor better than 8.6 Blackout?
In 375 Raptor vs 8.6 Blackout, it depends on the job. The 375 Raptor fires a heavier subsonic bullet and offers a stronger supersonic load. The 8.6 Blackout works in shorter barrels and is SAAMI standardized.
375 Raptor vs 8.6 Blackout: which is more powerful subsonic?
The 375 Raptor. At the same subsonic velocity, its 400 gr bullet carries roughly 20 to 35 percent more energy than a 300 to 330 gr 8.6 Blackout bullet.
Are 375 Raptor and 8.6 Blackout based on the same case?
Both ultimately trace to the .308 Winchester case family. The 8.6 Blackout is derived from the 6.5 Creedmoor case and necked up to .338, while the 375 Raptor is necked up to .375. Both use the standard .308 bolt face, but the cartridges are not interchangeable.
Can one suppressor work on both?
Yes, if it is rated for .375 caliber. The PLACID 375 is rated from 5.56 NATO through .375.
What twist rate does each cartridge use?
Chattahoochee Munitions uses 1:8 for 375 Raptor and offers 1:3 or 1:5 for 8.6 Blackout, depending on bullet weight.
What is the best barrel length for subsonic 375 Raptor?
A 12.5-inch barrel. Chattahoochee Munitions tests its 400 gr subsonic semi-auto load from a 12.5-inch barrel, and the shorter barrel keeps a suppressed firearm compact.
Does the CM10 use the same lower for 375 Raptor and 8.6 Blackout?
No. The CM10 375 Raptor uses a centerfeed system and modified MDT metal magazine; the CM10 8.6 Blackout uses conventional AR10 architecture with customized feed ramps.
Who designed the 375 Raptor?
The 375 Raptor was designed by Arne Brennan. Chattahoochee Munitions manufactures complete 375 Raptor firearms and ammunition for the cartridge.