News Releases

300 AAC Blackout (Medium Length Gas Tube)

July 17, 2013
Test Specifications/Components

Firearm Used: CMMG

Barrel Length: 16"

Twist: 1 x 8"

Case: Remington

Trim-to Length: 1.363"

Primer: Rem 7 1/2


The 300 AAC Blackout (300 BLK, or 7.62x35mm) was created by Advanced Armament Corp. and Remington in order to provide the military with a way to shoot .30 caliber bullets from the M4 platform with only a barrel change. It has since become popular for a wide range of uses including hunting and home defense.

The cartridge shares case-head dimensions and body taper with the .223 Remington. Not only does this allow for compatibility with existing magazines and bolts, but it allows reloaders to form their own brass from cut-down 5.56mm or .223 cases – ensuring brass supply even in the event of a shortage of factory brass.

The 300 AAC Blackout is a similar concept to previous wildcats, such as the 30-221 and 300 Fireball, as well as the proprietary 300 Whisper®, except that 300 BLK was the first to be a SAAMI approved cartridge and any company is free to make firearms or ammunition.

300 AAC Blackout is also finding use with hunters, who may not have been able to legally hunt with .223 in their state, and who prefer .30 caliber bullets for medium-sized game. It provides similar effectiveness to the 7.62x39 or the slightly more powerful 30-30 cartridges except works in the more up-to-date AR15 platform. Effective range for hunting is about 100-150 yards.

Click here to download Sierra Bullet's 300 AAC Blackout Load Data

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