.300 AAC Blackout, SAAMI short name 300 BLK, also known as 7.62×35mm is a rifle cartridge developed in the United States by Advanced Armament Corporation (AAC) for use in the M4 carbine. The .300 BLK purpose is to achieve ballistics similar to the 7.62×39mm Soviet cartridge in an AR-15 platform while using standard AR-15 magazines at their normal capacity.
While 5.56×45mm NATO has enjoyed widespread acceptance in military circles, the nature of the missions encountered by some special operations groups often demand a round that provides better performance than that available in the high-energy standard velocity rounds and subsonic performance greater than standard 9mm (the ubiquitous pistol round also commonly used in many SMGs.
In an effort to satisfy this need, the .300 AAC Blackout was developed. The .300 BLK can be seen as a SAAMI-certified version ofJones’ Wildcat .300 Whisper. The .300 AAC Blackout was created by Advanced Armament Corporation in cooperation with Remington Defense, under the direction of AAC’s Research and Development Director Robert Silvers and with the support of the company’s founder, Kevin Brittingham.
The .300 BLK project’s goals were:
- Create a reliable compact .30-caliber solution for AR platform
- Use existing inventory magazines while retaining their full capacity
- Create the optimal platform for sound and flash suppressed fire
- Create compatible supersonic ammo that matches 7.62×39mm ballistics
- Provide the ability to penetrate barriers with high-mass projectiles
- Provide all capabilities in a shorter, lightweight, durable, and low recoiling package
Meeting these goals allowed the development team to negate many of the perceived drawbacks inherent to other large caliber cartridges when used in the M4 platform. Colt Firearms and other arms makers had previously chambered AR-pattern rifles and carbines in various .30 caliber rounds but several issues were encountered. In the case of the 7.62×39mm, its relatively severe case angle caused feeding issues unless specially modified AK-47 magazines were used, and even then results were less than outstanding. Modified bolts were also needed owing to its larger case head diameter. Rounds such as the 6.8 SPC and 6.5 Grendel had similar part-interchangeability issues but did allow for the use of the standard M4/M16 30-round magazine albeit with a reduced capacity.