Ammo Brief: .300 AAC Blackout

by Tommy Grant

A quick look at .300 AAC Blackout, the king of .30-caliber AR cartridges.

The intent behind the .300 AAC Blackout was to offer a .30-caliber cartridge that would function in AR-15 rifles without a reduction in magazine capacity, that was also compatible with the standard bolt, and that would offer both supersonic and subsonic performance. The .300 AAC Blackout was developed by Advanced Armament Corporation (AAC), a subsidiary of the Freedom Group, and is almost identical to the .300 Whisper that was originally developed by J.D. Jones.

Another way of looking at the .300 AAC Blackout is as a standardization of the .300/.221 Wildcat cartridge. AAC standardized the case dimensions and submitted the cartridge to SAAMI, which has established the cartridge with a maximum average operating pressure of 55,000 psi.

General Comments

From a supersonic standpoint, the .300 AAC Blackout offers performance similar to the 7.62×39 Soviet cartridge. Hunters can expect performance on game to be similar to the 7.62×39 or the .30-30 Winchester. One thing hunters should recognize is that heavy match bullets at subsonic velocities will not expand in game animals. However, Lehigh Defense, working with J.D. Jones, has developed a subsonic bullet load that does offer expansion and good terminal performance at subsonic velocities.

Much of the appeal of the cartridge is its subsonic performance, but there is some contention that optimum performance from an AR-15 is unattainable with either supersonic or subsonic suppressed loads. It is also arguable that a single twist rate offers optimal stabilization with both a 125-grain bullet at 2,200 fps and a 220-grain bullet at 1,050 fps.

AAC suggests that a 1:8 twist be used, and most commercially offered rifles will come so equipped. DPMS, Windham Weaponry, Patriot Ordnance Factory, Advanced Armament, SIG Sauer, Noveske, Bushmaster, and others offer AR-15/AR-10 rifles in .300 AAC Blackout, and Remington offers four factory loads with 120-, 125-, 130- and 220-grain bullets. Both Remington 700 .300 AAC Blackout replacement barrels and loading dies are available.

Editor’s Note: This article is an excerpt of Gun Digest’s Cartridge’s Of The World.

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