Top 10 Reloaded Rifle Cartridges #8: .300 AAC Blackout
Date: Sep 20 2021
With the popularity these days of cartridges for long-range this and long-range that, it’s surprising the .300 Blackout has become one of the more popular rifle cartridges since its commercial introduction in 2010. Timing may have played a hand in the Blackout’s acceptance, as it was introduced by Advanced Armament Corporation (AAC) and its sister company, Remington, when the trend of tactical shooting started to build.
The Blackout, though, has many positive attributes. For one, the short cartridge fits in any gun design that accepts the .223/5.56, from single-shot handguns and compact bolt-action rifles to autoloading carbines, where it has been most successful. The Blackout shoots the complete range of .30-caliber bullets – from light bullets acceptably fast for hunting to 200-grain and heavier bullets plodding along at subsonic velocities.
The Blackout’s story goes back much farther than 2010. AAC had been working on a military cartridge when it was bought by Remington, backed by the Freedom Group, in 2009. The following year AAC and Remington introduced the .300 Blackout.
That year I toured the Remington ammunition plant in Lonake, Arkansas, mainly to observe the production of shotshells. At the nearby Remington shooting range, a couple of Remington engineers uncased an AR-15 and showed around the cartridge for which it was chambered. “It’s the .300 Blackout,” they said.
“It’s the .300 Whisper,” I replied.
The Blackout is indeed the .300 Whisper designed by J.D. Jones in 1992 by necking up .221 Fireball cases to accept .30-caliber bullets. The only difference between the Blackout and Whisper is Blackout chambers have a slightly longer leade.
Jones states on his website (sskindustries.com) that the “Whisper series of cartridges was developed as specific military, police, competition and recreational cartridges . . . ”
The website also states, “A Whisper cartridge must be capable of sub-sonic extreme accuracy with very heavy bullets for its caliber, i.e. 240 grains in 30, as well as moderate to high velocity while maintaining excellent accuracy with light bullets for the caliber, i.e. 125 at 2300 FPS in the 30.
“. . . the cartridge was designed as a multi-purpose cartridge from the beginning. Its design parameters, in addition to the ballistics quoted above, were that it must be capable of being used in the AR-15/M16 family of rifles, contenders and bolt action rifles as well as being easily suppressed.”
Quite a number of carbine bolt actions are chambered in Blackout. Most have 16-inch barrels. They range from Kimber’s Adirondack that weighs 4 pounds, 13 ounces, to the Ruger American Ranch rifle and Remington Model 700 Tactical.
Pretty much every AR-type rifle chambered in .223/5.56 NATO is also chambered in Blackout. A different barrel is the only requirement to change from .223 to Blackout, as both cartridges operate at the same 55,000 psi and use the same magazine and bolt face.
A SIG Sauer MCX VIRTUS Patrol was used to shoot the loads in the accompanying load table. The carbine is chambered in 5.56 or .300 Blackout. Only a barrel swap was required to change between the cartridges. Turning out two Torx screws loosened the barrel clamps, and the 5.56 barrel originally on the carbine pulled free of the upper receiver. After inserting a Blackout barrel and tightening the barrel clamp screws, I was in business shooting the Blackout.
I first shot SIG Sauer factory ammunition through the VIRTUS. Ammunition options are nearly unending, with Blackout ammunition also available from Barnes, Federal, Fiocchi, Gorilla, Hornady, HSM, Magtech, Nosler, Noveske, Remington, Silver State Armory, Streak, Underwood and Winchester. I’m sure there are others.
It seems someone is always comparing the Blackout to the .223/5.56, 7.62x39 and .30-30. So, ballistics-wise, let’s measure the Blackout against these three cartridges.
The .30-30 beats the Blackout every which way. The .30-30 shoots Sierra 150-grain bullets at 2,367 fps with 36.3 grains of CFE 223, and the Speer 125-grain TNT with 33.0 grains of H-335 at 2,587 fps when fired from the 20-inch barrel of my Winchester Model 94. Those velocities are an additional 300 fps faster than Blackout velocities with the same bullet weights.
The Blackout is America’s version of the 7.62x39 Russian, and the tactical crowd calls the Blackout the 7.62x35. I have been able to shoot Sierra 110-grain bullets at 2,511 fps loaded with Reloder 7, and Speer 125-grain bullets at 2,500 fps with CFE BLK powder from the 18.5-inch barrel of my CZ 527 Carbine 7.62x39. Tulammo is the fastest factory ammunition I have shot through a CZ, with its 124-grain FMJ bullets registering 2,405 fps at the muzzle. Advantage for the Russian round is 200 plus fps.
Ballistic charts show there is not much difference between the energy carried by 125-grain bullets fired at 2,235 fps from the Blackout and the .223 shooting 69-grain bullets at 3,000 fps, and 80-grain bullets existing the muzzle at 2,750 fps. The .22-caliber bullets carry about 50 foot-pounds of additional energy than the .30-caliber bullet by the time the three bullets have reached 100 yards. The .22-caliber bullets hang on to that energy advantage at 200 yards and enlarge the difference as distance increases.
Both bullets fired from a .223 drop half the distance of the .30-caliber bullets at distances from 150 to 400 yards when all three bullets are zeroed at 100 yards. The Blackout launching 165-grain bullets at 1,850 fps does not improve on those figures. A 220-grain bullet fired at 1,000 fps from the Blackout carries only about half the energy as 165-grain bullets. The heavy bullet drops like a hand-thrown brick.
To go out on a half-sawn limb, the Blackout was never designed to improve on the .223’s ballistics. The Blackout’s value is that it provides acceptable velocity from a 16-inch barrel with bullets that carry some persuasive weight.
Bullets for the Blackout run the gamut of lightweight projectiles traveling somewhat over 2,000 fps to heavy bullets plodding along at 1,000 fps. To determine how well light and heavy bullets expanded, I shot all the bullets listed in the accompanying load table into stacks of dry paper placed 35 yards from the muzzle of the SIG carbine. SIG-loaded Sierra 125-grain MatchKing bullets hit the paper at 2,080 fps, and handloaded Berger 110- and 125-grain bullets impacted at about 2,000 fps. All three bullets fragmented.
SIG 120-grain HT Solid Copper loads hit the paper at 2,150 fps. The hollowpoint peeled back into four petals to the bullet’s solid shank. The bullets expanded to nearly twice their original diameter, just like SIG advertises. The HT would make a great hunting bullet.
I doubted Speer 165-grain bullets would expand with a slow impact velocity of a 1,700 fps. But the jacket of the bullets ripped apart down to the base and lost their lead core. Berger 210-grain bullets were marginally stable when fired at 1,100 fps from the SIG’s barrel with its 1:6 rifling twist. A few of the bullets hit sideways on targets at 100 yards. The Bergers hit the paper going 960 fps. Recovered bullets looked like they had immediately turned sideways when they hit. The bullets bent in half and fairly well lost their lead core.
SIG-loaded Sierra 220-grain MatchKing bullets plowed into the paper at just under 1,000 fps. Their hollow points opened up, and the bullets expanded halfway down their length, doubling their initial width. The MatchKings would make a great bullet for shooting hogs.
Lehigh Defense has a great selection of bullets for all uses of the Blackout. Those bullets range from a 78-grain Close Quarters bullet, with an aluminum core and prestressed jacket designed to violently expand and limit penetration no more than 18 inches, to Maximum Expansion 194-grain Subsonic Bullets.
Lehigh states Maximum Expansion bullets do not expand in dry mediums like wood or drywall. Their hollowpoints are designed to expand at 750 to 1,200 fps upon contact with a fluid-based medium through hydraulic energy. I shot the bullets into the paper at 1,400 fps. The .60-inch-deep hollowpoints peeled back into four petals down to their solid copper base.
It seemed only a sprinkle of powder balanced my scale when weighing charges to handload the Blackout. Powder weights for 210-grain bullets looked especially light; how could those small amounts of powder even push those big bullets out the bore?
Powders for the Blackout are relatively fast burning, such as Accurate No. 11FS, 1680, 5744, LT-30 and No. 9, Alliant Reloder 7 and 10X, IMR-4227 and 4198, Hodgdon Lil’Gun and CFE BLK. CFE BLK worked well with the 110- to 210-grain bullets I used for the Blackout. CFE BLK traded back and forth with Lil’Gun for highest velocities. Accurate No. 11FS provided good accuracy with Berger 125-grain FB Target bullets with a velocity 200 fps faster than Lil’Gun.
Vertical spread of impact points of the different bullet weights was tremendous. With the SIG carbine sighted in to shoot 125-grain bullets on aim at 100 yards, Berger 110-grain bullets hit way over point of aim at 100 yards. In contrast, 210- and 220-grain bullets at subsonic velocities hit about 20 inches lower than the 125s.
Across the board, the Blackout produced low extreme velocity spreads that most likely resulted from powder charges held tightly in place by bullets in the Blackout case to promote a uniform powder burn. Over nine shots, SIG ammunition loaded with 120-grain HT bullets had an extreme velocity spread of 27 fps, Sierra 125-grain bullets provided a spread of 24 fps and Sierra 220-grain MatchKing bullets had an extreme spread of 16 fps. Handloads also produced even velocities. Berger 125-grain bullets shot with three different powders had an average extreme spread of 17 fps, Speer 165-grain bullets had a 29-fps velocity spread for three powders, and Lehigh Defense 194-grain bullets averaged 22 fps using three powders.
There is some concern that the small powder charges the Blackout burns may fail to generate enough gas to cycle an autoloader’s action. The SIG MCX VIRTUS Patrol is equipped with a two-position gas valve to meter the correct amount of gas used to cycle the rifle. Adjustments are made by pushing down a lever on either side of the valve through “windows” in the sides of the handguard. The left-side lever on the handguard has a “minus” and the right side a “plus” mark. SIG suggests setting the valve on “minus” for loads that generate supersonic velocities and “plus” for subsonic loads. I left the valve on the latter setting for all shooting. Every one of several hundred loads cycled without a hitch.
Handloading the Blackout was straightforward. A few loads resulted in compressed powder charges when seating bullets. The cartridges remained the same length after sitting for a day.
Some handloaders have reported the Blackout’s rather thin case necks fail to adequately hold bullets in place. A combination of compressed powder and the thrust of an autoloader’s bolt slamming closed can cause bullets to partially slide out of cases. Solutions include using a slightly narrower expander button in the sizing die, or loading bullets with a crimping cannelure to crimp case mouths. Most .30-caliber bullets, though, do not have a crimping groove. Those with a crimping groove most likely have it in the wrong place, unless they are specifically intended for the Blackout. Redding National Match dies come with a taper crimp die that solves all such problems.
If I can theorize why the .300 Blackout has become so popular, it is because it’s a great informal target and everyday-shooting cartridge. Cartridges, handloads at least, are relatively inexpensive, and recoil is negligible. I shot the SIG carbine at targets, and my son shot it at ground squirrels. The back-and-forth slam of the bolt created more recoil than the actual firing of cartridges. From there the Blackout readily adapts to short-range hunting with an assortment of bullet weights and styles.