The AR is a rugged and reliable platform that has proved itself on the battlefield for 50 years, but its 5.56×45 mm (.223 Rem.) chambering is considered to be on the smaller end of the power spectrum by many shooters. While popular, the standard AR round is basically considered illegal for hunting deer in many states. Of course, AR rifles and its variations can be obtained in larger calibers, such as .300 AAC Blackout.
The .300 AAC Blackout was developed by Advanced Armament Corp. as a more-powerful caliber for the M4 (AR-15) rifles using standard magazines without sacrificing ammo capacity. It was designed primarily for Special Ops units needing better performance in their rifles for tactical engagements. It provides the knockdown of a .30-caliber bullet without a huge increase in recoil, and reliable run for both suppressed and unsuppressed rifles.
Word gets out in the civilian world, shooters realize the benefits of the .300 AAC Blackout, and manufacturers like Daniel Defense begin producing rifles in this caliber. Not long after hunters also begin wanting an AR in this chambering, leading Daniel Defense to produce a rifle in .300 AAC Blackout under its hunting brand Ambush Firearms.
The Ambush 300 BLACKOUT is a gas operated semi-auto in the standard M4 design, including its controls. The safety, magazine release and bolt catch are all located in the standard locations. It’s listed as multi-caliber as it fires both .300 AAC Blackout and .300 Whisper ammunition, and since everything but the barrel is the same as Daniel Defense’s 5.56 rifles, the barrel can be swapped for additional calibers. Features a 16-inch cold-hammer forged barrel with a salt-bath nitride finish with 1:8-inch twist rifling.
It features a two-piece Picatinny rail along the top of the receiver with indexing marks for attaching optics in the same position every time, along with three, 2.5-inch Picatinny rail sections on the front of the modular float rail for mounting lights, lasers, bipods and other accessories.
Other features on the 300 BLACKOUT include some inspired by the needs of Special Forces rather than hunters, such as a threaded barrel for attaching a suppressor, with a protector on the end, and a charging handle that is more easily accessible when using optics. The Mossy Oak finish on the test model was smooth and well applied, though the deflector quickly showed signs of the finish chipping once shooting began.
The 300 BLACKOUT breaks down just like any AR-15 rifle, and comes with a single five-round PMAG magazine, which makes sense as many states limit magazine capacity for hunting.
As for accuracy, the Ambush 300 BLACKOUT was excellent with multiple consecutive five-shot groups measuring under an inch with three different loads. A large part of this was due to the excellent two-stage trigger that started with just a little bit of un-resisted take-up before breaking at just over 4 pounds.
The best load was Hornady’s .300 Whisper 110-grain V-MAX load with a best group of .7 inches and an average of .92 inches at 100 yards from a rest. This combination also obtained a 1.62-inch 15-round group at 50 yards.
The 110-grain load also performed best in function as both of the subsonic loads—Hornady’s .300 Whisper 208-grain A-MAX and Federal’s 220-grain .300 AAC Blackout—had issues with both loading and ejecting because of the heavier bullets and lower velocity, with the Federal load having the most issues.
This was to be expected as Ambush claims that firing subsonic loads un-suppressed can cause failures to feed, failures to eject and failures to fire. Testing proved this to be true, but talking with a representative of Daniel Defense revealed that they had recently “tweaked” the gas system to better run with subsonic loads. Even having to load each round individually, the Federal loads showed excellent accuracy, averaging just over an inch at 100 yards, while the Hornady 208-grain load averaged 1.3 inches.
That .30-caliber bullet gives the Ambush 300 BLACKOUT accuracy and knock-down, and its excellent features make it a prime choice for hunters desiring more power in an AR-type rifle.
Source:Paul Rackley AmericanRifleman.org AmbushFireArms.com
Transcribed by by Jon Hines