300 AAC Blackout (300BLK)


Hey there! Allow me to introduce you to the Advanced Armament Corp. 300 AAC Blackout (300BLK) system. This incredible system was specifically designed to launch 30 caliber projectiles from the AR platform while maintaining the magazine capacity and compatibility with the standard bolt.

If you’re looking for some serious firepower, the full power 115-125 grain ammunition of the 300BLK matches the ballistics of the 7.62x39mm AK round, but it goes a step further by surpassing the performance of the 5.56mm round. With its higher-mass projectiles, the 300BLK delivers a more impactful effect on the target.

On the other hand, if you prefer a quieter approach, you can opt for subsonic cartridges which work exceptionally well with a sound suppressor. The 220 grain Sierra OTM (open-tip match) bullets in these cartridges outperform a 9mm MP5-SD in terms of penetration and long-range accuracy.

Now, the best part is that the 300BLK system offers affordable ammunition and brass prices. You can get Remington 115 grain UMC ammo for just $12.99 a box (MSRP), and it’s definitely not lacking in quality. This ammo comes with waterproofed primers, crimped and cannelured open-tip match bullets, and a low-drag design.

In terms of performance, the 300BLK has some impressive stats. At 300 meters, it carries 16.7% more energy than the 7.62x39mm round. According to M4 military standards for hit probability, its maximum effective range is 440 meters with a 9-inch barrel, and 460 meters with a 16-inch barrel.

What’s fascinating is that the 300BLK fired from a 9-inch barrel has the same energy at the muzzle as a 14.5-inch barrel M4, and it even retains about 5% more energy at 440 meters, despite having a much shorter barrel.

If you’re into hunting, think of the 300BLK as a similar experience to using a 30-30, but in the convenience of an AR platform. After your hunting trip, you can easily switch out your 5-round magazine for a 30-round one for plinking or home defense.

And when it comes to ammo, Remington has got you covered with their Premiere AccuTip 125 grain rounds. The best part is, this cartridge has gained widespread support in the industry, with over 60 companies already announcing or selling products for it.

One notable advantage of the 300BLK is its high efficiency, which allows it to use less powder compared to the 5.56mm round. As a result, shooting a rifle chambered in 300BLK is comfortable, even with a short barrel.

If you’re interested in reloading, you can find reloading dies from Forster products, as well as reamers and headspace gauges from Pacific Tool and Gauge.

300 AAC Blackout RESOURCES

The 300 AAC Blackout cartridge just claimed the top spot at the MultiGun Nationals!

Discussion Forum – 300BlkTalk.com



The Design Objectives Behind the Creation of The 300 AAC Blackout Cartridge

The main goals were to develop a reliable and compact 30-caliber solution specifically for the AR platform. They wanted to make sure that this new cartridge could work seamlessly with existing inventory magazines while still retaining their full capacity.

Another important objective was to create the optimal platform for sound and flash suppressed fire. They wanted to ensure that shooters could enjoy a quieter and less flashy shooting experience.

To match the ballistics of the 7.62x39mm round, the designers aimed to develop compatible supersonic ammunition. This meant that the 300 AAC Blackout had to deliver similar performance to the popular 7.62x39mm round while offering some unique advantages.

One of those advantages is the ability to penetrate barriers effectively. The designers wanted to provide high-mass projectiles that could easily penetrate barriers when necessary. This feature adds versatility to the cartridge, allowing it to perform well in different scenarios.

Last but not least, they wanted to achieve all of these capabilities in a package that is lightweight, durable, and has low recoil. This ensures that shooters can enjoy a comfortable shooting experience without compromising on performance.

The 7.62x39mm Cartridge Wasn’t Considered for A Few Reasons

First, it has an extreme taper, which can lead to reliability issues when feeding in AR magazines. This taper also reduces the magazine capacity, which is a drawback for many shooters.

Moreover, the cartridge taper causes significantly higher bolt thrust, which can worsen the weaknesses of the AR bolt. It requires a larger bolt face, further reducing the strength of the bolt locking lugs, which is not ideal considering the limitations of the AR bolt.

Another factor is the limited projectile selection for the 7.62x39mm cartridge. It has a diameter of 0.311 inches, which is not a commonly available option for most modern bullets. This lack of projectile variety can limit the versatility and performance of the cartridge.



  • 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)

Handloading Your Own Ammunition for The 300 AAC Blackout (300BLK)

For most supersonic loads, Hodgdon H110 is a recommended powder choice. However, when it comes to subsonic loads, there are some specific considerations. Many published loads may not be optimal for the 300BLK upper, as they were originally developed for Thompson CenterĀ® single-shot pistols or by individuals unaware of magazine limitations. It’s important to avoid using these loads, as they don’t account for proper functioning in automatic rifles.

When selecting a subsonic load, look for one that results in a cyclic rate of 700 rpm or more. This ensures smooth and reliable cycling of the weapon. A recommended powder for subsonic loads is A1680, as its bulk density matches the case capacity and it generates sufficient gas pressure to cycle the weapon effectively.

Remember to exercise caution and follow recommended load data when handloading ammunition for the AAC 300BLK. Safety is paramount, so always adhere to established guidelines to ensure a safe and enjoyable shooting experience.

If you’re looking for a suggested subsonic load for the 300 AAC Blackout (300BLK), here’s a recipe you can try:

  • Start with R-P 300 AAC Blackout brass.
  • Use Remington 7.5 primers.
  • For the powder charge, begin with 11.2 grains of A1680 powder. Adjust the powder charge as needed based on your specific requirements. It’s worth noting that factory ammo typically achieves a velocity of 1010 fps when fired from a 16″ barrel.
  • Ensure that the case length measures 1.368 inches, with a tolerance of +0.000 and -0.020 inches.
  • Load Sierra 220 MK (MatchKing) bullets and set the overall length (OAL) to 2.120 inches. This length has been found to be optimal for reliable feeding from USGI magazines.
  • Finally, it’s important to note that the chamber pressure for this load should be around 21,100 psi.