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How the Military Helped Develop 300 Blackout

With the launch of our new site, we feel it’s only fitting that we kick things off with a little history about this unique, dual-function rifle cartridge. After all, any newcomer to the AR 15 platform – and any round worthy of competing against the tried and true .223 and 5.56 NATO – is worthy of analysis.

Wildcats, Whispers, and Fireballs

The (not so) new 300 AAC Blackout, whose SAAMI short name is simply 300 BLK, is a 7.62x35mm dual-purpose rifle cartridge that originated as a wildcat round, built by the Gunsmithing hands of industry legend J.D. Jones of SSK Industries, in the 1990s. The round that would become a favorite of special warfare operators started off as a member of Jones’ Whisper family of cartridges and was sometimes (confusingly) referred to as the .300 Fireball.  

There’s good reason for this misnomer: The .300 Whisper was based on the .221 Fireball casing. Jones necked it up to a .30 caliber and slapped a large, fat, heavy 220-grain bullet on top. Jones himself developed the .300 Whisper to provide the same utility that the SOCOM community wanted in a new rifle round: Supersonic loads that provided ballistics similar to 7.62x39mm, and subsonic loads that offered as much punch as a .45 ACP or sub gun, while affording superior range.

The Military’s Match Made in Heaven

But how and why did the .300 Whisper make its way to the U.S. Military? In short, the military’s special operations community wanted a rifle that was shorter and more compact, while still providing acceptable energy and ballistic data. There are problems with the 5.56 NATO that grow as barrel lengths shorten, and so the U.S. Military reached out to one Kevin Brittingham, founder of AAC (the current owner of the official .300 Blackout round). Brittingham happened to have a great partnership with J.D. Jones, and the two worked together to modify the .300 Whisper into a SAAMI-approved round that the military could rely on.

From SSK to AAC

Brittingham remarks, “They had tried .300 Whisper, and J.D. Jones delivered this group of a few samples that worked great. They delivered them 30, 7 of them worked.” With minor modifications by AAC (small enough that .300 Whisper and .300 Blackout are considered interchangeable), the round was officially designated the .300 AAC Blackout. It was made ready for service overseas.

There are many reasons why .300 Blackout is a popular round in the civilian AR 15 world: It’s one of the only commercially available black rifle rounds that can be fired effectively all four ways, without any gunsmithing: Subsonic suppressed, subsonic unsupressed, supersonic suppressed, and supersonic unsupressed. What’s more, .300 Blackout reliably sits in and cycles from standard AR 15 magazines.

Dead Quiet, Accurate, Versatile

The last two aspects make it particularly appealing: When subsonic and suppressed, .300 Blackout is so quiet that many remark the trigger reset is louder than the actual round itself. And with a standard, 16” barrel, community shooters remark they average sub-MOA accuracy with both loads at 100 yards. Other users report similar accuracy using just a 9” barrel with supersonic rounds.

Why You Want an AR 15 in .300 Blackout

So, in the end, .300 Blackout is quite the amazing (not so) little round for any AR 15 owner or prospect. It offers more muzzle energy than 5.56, it can be suppressed at the drop of a hat, it offers more damage and penetration for those “SHTF” scenarios, it’s accurate in any load, and bonus: It can be made by cutting down some simple, factory 5.56 brass. That’s why we’re here today, to help you bring this versatile round to your gun safe and range day in the form of a kick-ass AR 15. Get building!


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