8.6mm Blackout

8.6mm Blackout (8.6×43 mm), sometimes referred to as 8.6 BLK,^[1] is a centerfire rifle cartridge developed by the firearms manufacturer Q, LLC.^[6] It utilizes a shortened case from the 6.5mm Creedmoor necked up to an 8.6 mm caliber (8.585 mm or 0.338 in diameter) projectile. 8.6 Blackout is designed for use in bolt-action rifles or as a caliber conversion for AR-10 style rifles.

8.6mm Blackout
From left to right: 9x19mm, 45 ACP, 5.56x45mm, 300 BLK, 8.6 BLK, 6.5 Creedmoor, 7.62x51mm, 30-06 Springfield
Type	Centerfire rifle
Place of origin	United States
Production history
Designer	Q, LLC
Produced	2022–present
Specifications
Parent case	6.5mm Creedmoor[1]
Case type	Rimless, bottleneck
Bullet diameter	8.58 mm (0.338 in)
Neck diameter	9.40 mm (0.370 in)[1]
Shoulder diameter	11.531 mm (0.4540 in)[1]
Base diameter	11.946 mm (0.4703 in)[1]
Rim diameter	12.01–0.25 mm (0.4728–0.0098 in)[1]
Rim thickness	1.37–0.25 mm (0.0539–0.0098 in)[1]
Case length	42.80 mm (1.685 in)[1]
Overall length	63.25–71.75 mm (2.490–2.825 in)[1]
Rifling twist	76–102 mm (1:3–1:4")
Primer type	Small rifle or large rifle (depending on casing)
Ballistic performance
Bullet mass/type Velocity Energy 18.66 g (288 gr) Gorilla Fracturing Subsonic 320 m/s (1,000 ft/s) 955.5 J (704.7 ft⋅lbf) 13.61 g (210 gr) Gorilla Barnes TSX Supersonic 600 m/s (2,000 ft/s) 2,454 J (1,810 ft⋅lbf) 18.47 g (285 gr) Fort Scott Solid Copper TUI 321 m/s (1,050 ft/s) 945.7 J (697.5 ft⋅lbf) 22.68 g (350 gr) Steinel Solid copper Hollow Point 360 m/s (1,200 ft/s) 1,540 J (1,140 ft⋅lbf)
Test barrel length: 406 mm (16.0 in) (12 in for Gorilla supersonic) Source(s): [2][3][4][5]

The only required modification to convert an existing .308 Winchester-chambered rifle to 8.6mm Blackout is the replacement of the barrel.^[7] The 8.6 Blackout shares the same case head and bolt diameter as its parent cartridge, 6.5mm Creedmoor. All other components of a standard AR-10 rifle are compatible. Modifications to the operating system such as the buffer, buffer spring and gas system may be made in order to optimize functionality of the firearm. 8.6 Blackout fits in standard, unmodified .308 Winchester or 6.5 Creedmoor magazines with no effect on capacity.^[8]

The 8.6 Blackout is designed for barrels using a 76 mm or 102 mm (1:3 in or 1:4 in) twist rate and bullet weights between 10.4–14.6 g (160–225 gr) for supersonic loads and 18.5–22.7 g (285–350 gr) for subsonic loads.^[9] The "fast" twist rate 8.6mm Blackout is designed for was intended to create better expansion and more terminal energy transferred to the target through the "blender effect" of a rapidly-spinning subsonic bullet.

Platforms

Manufacturer	Model	Type	Country
Q	Fix[10][11]	Bolt action rifle	United States
Q	Boombox[12]	Semi-automatic rifle	United States
Chattahoochee Munitions	CM7S [13]	Bolt action rifle and pistol	United States
Chattahoochee Munitions	CM10 [14]	Semi-automatic rifle and pistol	United States
Faxon Firearms	Sentinel[15]	Semi-automatic rifle	United States
Gorilla Ammunition	GF-10[16]	Semi-automatic rifle	United States
Bear Creek Arsenal	BC-10 [17]	Semi-automatic rifle	United States
Rossi	LWC[18][better source needed]	Single shot rifle	United States
Robinson Armament	XCR-M (Mini & Mid)[19]	Semi-automatic rifle	United States

See also

• 9×39mm
• .300 AAC Blackout
• .338 Whisper
• .338 Federal
• 6.5 Creedmoor
• .30 Thompson Center