8.6 Blackout vs .300 Blackout: Which Is Right For You?

The 8.6 Blackout and the .300 Blackout are both suppressor-optimized blackout cartridges designed to run on the AR platform — but they’re built for different missions. This comparison breaks down the key differences in performance, platform, cost, and application so you can make the right call.

Quick Comparison: 8.6 Blackout vs .300 Blackout

Specification	8.6 Blackout	.300 Blackout
Caliber	.338″ (8.6mm)	.308″ (7.62mm)
Platform	AR-10 / GF-10 (.308 bolt face)	AR-15 (5.56 bolt face)
Subsonic bullet weight	285–342gr	200–220gr
Supersonic bullet weight	185–210gr	110–125gr
Subsonic muzzle energy	~900–1,100 ft-lbs	~450–500 ft-lbs
Supersonic muzzle velocity	~2,400 fps (210gr)	~2,200 fps (110gr)
Magazine compatibility	.308/AR-10 mags	Standard AR-15 mags
Ammo cost	Higher (specialty)	Lower (widely available)

Platform Differences

This is the biggest practical difference between the two cartridges. .300 Blackout runs on a standard AR-15 lower — you can convert virtually any 5.56 AR-15 to .300 Blackout with just an upper swap. The bolt, lower, and magazines all stay the same. This makes the .300 Blackout the most accessible suppressor-optimized cartridge on the market.

8.6 Blackout runs on the AR-10/.308 platform, specifically on a modified .308 bolt face with a rebated rim. Gorilla Firearms designed the GF-10 platform specifically for this cartridge. You need an AR-10 lower and the GF-10 upper — you cannot run 8.6 Blackout on an AR-15.

Subsonic Performance: A Major Advantage for 8.6 Blackout

This is where 8.6 Blackout separates itself. The .338 caliber bore allows for dramatically heavier subsonic projectiles — 285gr to 342gr — compared to .300 Blackout’s 200–220gr ceiling. More bullet weight at the same subsonic velocity means significantly more muzzle energy.

• 8.6 Blackout (285gr at 1,050 fps): ~695 ft-lbs of energy
• .300 Blackout (220gr at 1,010 fps): ~498 ft-lbs of energy

That’s roughly 40% more energy at the muzzle from the 8.6 Blackout in subsonic configuration. When you’re hunting deer, hogs, or larger game suppressed, that energy difference translates directly to terminal performance and ethical kills.

Supersonic Performance

In supersonic configuration, the 8.6 Blackout again has a significant energy advantage due to its larger bore diameter and heavier bullets. The 210gr Barnes TSX at supersonic velocities hits harder than any .300 Blackout supersonic load. However, the .300 Blackout’s lighter supersonic projectiles (110gr) have flatter trajectories at typical hunting distances.

Which Is Right For You?

Choose .300 Blackout if:

• You already own an AR-15 and want a suppressor-compatible caliber with a simple upper swap
• Ammo cost and availability are top priorities
• You’re hunting deer-sized game or smaller
• You want the widest possible ammo selection

Choose 8.6 Blackout if:

• You want the maximum suppressed terminal performance available on a semi-auto platform
• You’re hunting larger game — elk, black bear, or wild boar — suppressed
• You’re building a purpose-built suppressed hunting or tactical rifle from the ground up
• You want a cartridge developed by the same manufacturer as your ammo

Shop 8.6 Blackout and .300 Blackout Ammo

Gorilla Ammunition manufactures both cartridges in-house. Browse our full lineups:

• 8.6 Blackout Ammo — Subsonic, supersonic, and bulk loads
• . 300 Blackout Ammo — 20-round boxes and 160-round bulk buckets

Pick Your Blackout — Then Stock Up

Both calibers in stock now. Fast, discreet, fully insured shipping across the USA.

SHOP 8.6 BLACKOUT SHOP 300 BLACKOUT