30 caliber rounds but encountered problems. Colt Firearms and other arms makers had previously chambered AR-pattern rifles and carbines in various.

The new cartridge was intended to negate many of the perceived drawbacks inherent to other large caliber cartridges used in the M4. 300 AAC Blackout in cooperation with Remington Defense. While 5.56Г—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 9Г—19mm Parabellum (the ubiquitous pistol and submachine gun) round. The 300 AAC Blackout utilizes standard 5.56mm NATO magazines and components with the exception of the barrel. The cartridge yields increased performance in shorter barrels and effective subsonic performance for suppressor use when compared to 5.56mm NATO. ), also known as 7.62Г—35mm, is an intermediate cartridge developed in the United States by Advanced Armament Corporation (AAC) for use in the M4 carbine. 300 AAC Blackout (designated as the 300 BLK by the SAAMI and 300 AAC Blackout by the C.I.P.

300 AAC Blackout plastic tipped, left, compared to.

Subsonic 300 blackout hunting ammo