Skip to main content

.300 AAC Blackout Cartridge: Perfect for AR-15s

Looking for an AR-15 cartridge to shoot rather than the 5.56 NATO? If so, the .300 AAC Blackout is a viable option, especially for hunting medium size game.

.300 AAC Blackout Cartridge: Perfect for AR-15s
The .300 AAC BLK is an efficient .30 caliber cartridge designed to function in the AR-15. Left–Right: 9x19, 5.56x45, 7.62x39, .300 BLK 110-grain TAC-TX Supersonic, .300 BLK 220-grain OTM Subsonic and 9x39.

Why should you consider an AR in .300 AAC Blackout rather than 5.56 NATO? If you only have one AR-15 then I recommend 5.56. However, if you already have a 5.56 or are looking specifically for something you can use hunting pigs and medium size game, then a .300 BLK is a viable option. If you are looking to shoot suppressed, well the .300 BLK is hard to beat.

While the .300 BLK cartridge has been with us for about a decade, the concept is much older. Perhaps the best known predecessors are the .300/.221 Fireball and .300 Whisper from JD Jones.

Both of these are wildcats and never really made a big splash. In 2010 though Robert Silvers, the Research and Development Director of Advanced Armament Corp. (AAC), was contacted by a government customer with a requirement for a cartridge firing a .30 caliber projectile capable of being chambered in a M4 carbine.

He was asked if AAC could produce firearms with Remington Defense manufacturing .300/.221 Fireball-type ammunition. This request would lead directly to Silvers developing what became the .300 BLK cartridge.


I have known Silvers for almost 20 years now, so to get the story on the origins of this cartridge I contacted him directly. What follows is, in his words, how the cartridge was developed:


“With Remington already doing the .221 and .17 Fireball, it was a natural to do the .30 caliber. But Remington is a SAAMI company and only makes SAAMI approved ammunition. So we had to create the final specifications of the cartridge, and seek SAAMI acceptance.

“The problem with calling it the .300 Fireball was two-fold. One is that the cartridge is low visibility, and Fireball seems like the opposite of that. The other is that there were too many chamber drawings for wildcat versions called .300 Fireball. If we picked that name, we would have to clear compatibility with these existing chambers, and that would limit velocity potential because we would have to pressure-test the ammo in the tightest one.

“.300 Whisper is a proprietary name which requires licensing, and SAAMI does not accept trademarked names. Also, I did not want to use it because it implies subsonic is the primary use—and that is not the way I see the cartridge. 300 AAC Blackout was designed to be the most powerful way to shoot .30 caliber from an AR-15 while remaining compatible with normal 30-round magazines. A fresh name was needed so that we could design the chamber with the exact specs we thought best. 300 AAC Blackout is a name both consistent with full power ammo, but yet stealthy at the same time.”

And just what was the new cartridge developed for and intended to do? The goals of the project were fairly straightforward:


  • Create a reliable .30 caliber cartridge compatible with the AR platform.
  • Create the optimal platform for sound and flash suppressed fire.
  • Develop supersonic ammunition which matches 7.62x39mm ballistics.
  • Provide the ability to penetrate commonly encountered barriers.
  • Utilize existing M16 magazines at their full capacity.
  • Encapsulate these capabilities in a lightweight, low recoiling yet durable package.

Silver’s solution requires only a barrel change to convert from 5.56 to .300 BLK. Existing 5.56 AR bolts and magazines can both be utilized. By using the standard-size bolt, the locking lugs are not weakened as happens with cartridges that require a larger bolt face. So this problem is eliminated. By using a standard 5.56 magazine the need for expensive proprietary magazines is eliminated.

The .300 BLK’s performance is a bit different than conventional rifle cartridges in that it offers two distinct levels of performance. A shooter can select either heavy (200 to 240+ grains) subsonic loads or lighter (110 to 140+ grains) supersonic loads.

Subsonic loads are simply those that drive their projectiles at less than the speed of sound. The speed of sound in dry air at 68 degrees is 1,126 fps. Heavy efficient projectiles with high ballistic coefficients retain their velocity and energy well. So despite their low initial velocity, a 200+ grain .30 caliber subsonic load can provide acceptable performance on medium size game. More importantly it can do this, when teamed with a sound suppressor, at a very pleasant and safe noise level.


GET THE NEWSLETTER Join the List and Never Miss a Thing.

Recommended Articles

See More Recommendations

Popular Videos

Black Hills Evolution of Rifle Cartridge: .308 Win. 175 Gr. Match

Black Hills Evolution of Rifle Cartridge: .308 Win. 175 Gr. Match

David Fortier talks with Jeff Hoffman of Black Hills Ammunition about the evolution of the .308 Win. 175 Gr. Match bullet.

Ruger Launches New American Rifle Predator in 6.5 Grendel

Ruger Launches New American Rifle Predator in 6.5 Grendel

OSG's Lynn Burkhead and Ruger's Matt WIlson kick off SHOT Show 2018 by taking a look at the Ruger Predator.

All About .300 Blackout

All About .300 Blackout

The .300 Blackout is here to stay, and we take some time to look at new technology surrounding this cartridge. Next, we pit subsonic rivals against each other before stretching the legs of this CQB round out to 600 yards from a short 9-inch barrel.

Mossberg Patriot Predator 6.5 PRC Revew

Mossberg Patriot Predator 6.5 PRC Revew

Mossberg Patriot Predator 6.5 PRC Revew

See More Popular Videos

Trending Articles

SIG SAUER adds to its Elite Match ammo line with the 30-06 Springfield.New 30-06 Springfield Elite Match Ammo from SIG SAUER Ammo

New 30-06 Springfield Elite Match Ammo from SIG SAUER

Rifleshooter Online Editors - April 03, 2019

SIG SAUER adds to its Elite Match ammo line with the 30-06 Springfield.

The road to the famous Remington 700 rifle was paved with classics like the models 725 and 30s.Before the Remington 700 Historical

Before the Remington 700

Payton Miller - August 20, 2020

The road to the famous Remington 700 rifle was paved with classics like the models 725 and 30s.

Some history and reloading recipes on five popular .17-caliber cartridges, including the .17 Ackley Hornet, .17 Hornady Hornet, .17 Mach IV, .17 Remington Fireball and .17 Remington..17-Caliber Reloading Data and History for 5 Cartridges Reloading

.17-Caliber Reloading Data and History for 5 Cartridges

Layne Simpson - June 05, 2019

Some history and reloading recipes on five popular .17-caliber cartridges, including the .17...

The new Hammerli TAC R1 22 C, an AR-15 style .22 rimfire rifle, is the first product in the company's new Defense line.Hammerli TAC R1 22 C Review Reviews

Hammerli TAC R1 22 C Review

James Tarr - August 12, 2020

The new Hammerli TAC R1 22 C, an AR-15 style .22 rimfire rifle, is the first product in the...

See More Trending Articles

More Ammo

This cartridge clash between the .45-70 Gov't and .450 Bushmaster is less about the minute details of the cartridge and more about your personal taste in firearms..45-70 vs .450 Bushmaster — Cartridge Clash Ammo

.45-70 vs .450 Bushmaster — Cartridge Clash

Brad Fitzpatrick - May 21, 2020

This cartridge clash between the .45-70 Gov't and .450 Bushmaster is less about the minute...

Looking for an AR-15 cartridge to shoot rather than the 5.56 NATO? If so, the .300 AAC Blackout is a viable option, especially for hunting medium size game..300 AAC Blackout Cartridge: Perfect for AR-15s Ammo

.300 AAC Blackout Cartridge: Perfect for AR-15s

David Fortier - March 18, 2020

Looking for an AR-15 cartridge to shoot rather than the 5.56 NATO? If so, the .300 AAC...

The .26 Macho can accurately propel the 120-grain Sierra bullet to speeds great enough to allow the bullet to create a devastating wound channel on deer-size game..26 Macho Cartridge — Wildcat Notes Ammo

.26 Macho Cartridge — Wildcat Notes

Jason Stanley - September 23, 2020

The .26 Macho can accurately propel the 120-grain Sierra bullet to speeds great enough to...

Weatherby has announced two new rifles — the Backcountry and the Backcountry Ti — and the 6.5 RPM non-belted cartridge, their first non-venturi design.New Weatherby Backcountry Rifles, 6.5 RPM Cartridge Announced Bolt-Action

New Weatherby Backcountry Rifles, 6.5 RPM Cartridge Announced

J. Scott Rupp - September 06, 2019

Weatherby has announced two new rifles — the Backcountry and the Backcountry Ti — and the 6.5...

See More Ammo

Magazine Cover

GET THE MAGAZINE Subscribe & Save

Digital Now Included!

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE Arrow

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Phone Icon

Get Digital Access.

All Rifle Shooter subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit mymagnow.com and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now