300 AAC Blackout (300BLK)

Introducing the Advanced Armament Corp. 300 AAC Blackout (300BLK). This system was developed to launch 30 caliber projectiles from the AR platform without a reduction in magazine capacity and compatible with the standard bolt.

Full power 115-125 grain ammunition matches the ballistics of the 7.62x39mm AK, and eclipses 5.56mm with much higher-mass projectiles for a more dramatic effect on the target. Or choose subsonic cartridges for optimal use with a sound suppressor – 220 grain Sierra OTM (open-tip match) bullets vastly outperforms a 9mm MP5-SD in penetration and long range accuracy.

Ammo and brass prices are low – Remington 115 grain UMC ammo is $12.99 a box MSRP – and it is not bare bones. It has waterproofed primers, crimped and cannelured open-tip match bullets, and a low-drag design.

At 300 meters, 300 BLK has 16.7% more energy than 7.62x39mm. Max effective range, using M4 military standards for hit probability, is 440 meters for a 9 inch barrel, and 460 meters for a 16 inch barrel. 300 BLK from a 9 inch barrel has the same energy at the muzzle as a 14.5 inch barrel M4, and about 5% more energy at 440 meters – even though the barrel is much shorter.

For hunting – think of it as like a 30-30 but from an AR. After you are done, you can remove your 5-round magazine and put in a 30 for plinking or home defense. For ammo, Remington has you covered with the Premiere AccuTip 125 grain. Want industry-wide support? Over 60 companies have already announced or sell products.

Due to the high efficiency of the cartridge, less powder is used than 5.56mm, which results in a rifle that is a comfortable to shoot – even with a short barrel.

Reloading dies available from Forster products, Reamers and headspace guages available from Pacific Tool and Gauge.

300 AAC Blackout RESOURCES

300 AAC Blackout Used for 1st Place Win at MultiGun Nationals

300BlkTalk.com Discussion Forum




  • Create a reliable compact 30-cal solution for the AR platform
  • Utilize existing inventory magazines while retaining their full capacity
  • Create the optimal platform for sound and flash suppressed fire
  • Create compatible supersonic ammo that matches 7.62×39 ballistics
  • Provide the ability to penetrate barriers with high-mass projectiles
  • Provide all capabilities in a lightweight, durable, low recoiling package


  • Extreme cartridge taper
  • Reduces reliability of feeding in AR Magazines
  • Reduces Magazine capacity
  • Cartridge taper induces considerably higher bolt thrust-exacerbating the AR Bolt’s weaknesses
  • Requires a larger Bolt Face which reduces Bolt Locking Lug strength-exacerbating the AR Bolt’s weaknesses
  • Limited projectile selection
  • 0.311″ diameter not a common option in most modern bullets


  • Overview of the AAC 300BLK development, comparisons to other common ammunition, ballistics info, and host weapon system comparisons. (>>Download PDF (6.69MB)
  • Infosheet on the AAC 300BLK PDW 9″ AR upper. (>>Download PDF (254KB)
  • Infosheet on the specially-developed 762-N-6 silencer. (>>Download PDF (234KB)
  • 300 AAC BLACKOUT Black Rifle Manual. (>>Download PDF (1.6MB)
  • Initial Gel test results for some 300 BLK ammo. (>>Download PDF (8MB)


If you load your own ammo, pay special attention to all of the normal safety practices. Recommended powder for most supersonic loads is Hodgdon H110.

For subsonic, there are special requirements and nearly all published loads are non-optimal for the 300 BLK upper. Many existing loads were developed for Thompson CenterĀ® single-shot pistols, or for ARs by people not aware of the magazine limitations. These loads pay no attention to automatic rifle function and should not be used. Look for a load which results in a cyclic rate of 700 rpm or more. A1680 is recommended because its bulk density matches the case capacity and it will generate enough gas pressure to cycle the weapon.

Suggested subsonic load:

  • R-P 300 AAC BLACKOUT brass
  • Remington 7.5 primers
  • 11.2 grains of A1680 powder (Adjust powder charge down as needed. Factory ammo is 1010 fps for 16″ barrel)
  • Case length is 1.368 +0.000 -0.020
  • Sierra 220 MK loaded to 2.120 OAL (this length is optimal for reliable feeding from USGI magazines)
  • Chamber pressure 21,100 psi.

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