Advances in AR-15 Ammo


These four popular AR-15 cartridges show the versatility the platform offers. From left to right - .223 Remington, 6.5 Grendel, 6.8 Remington SPC and .450 Bushmaster.

These four popular AR-15 cartridges show the versatility the platform offers. From left to right – .223 Remington, 6.5 Grendel, 6.8 Remington SPC and .450 Bushmaster.

Factory ammunition runs from 90 to 130 grains and is loaded by Hornady, Alexander Arms, Wolf, and Black Hills, though the latter is headstamped .264 LBC-AR. Alexander Arms recently relinquished the trademark claim, which recently lead to the Grendel’s SAMMI standardization, which should open the doors for more companies to produce ammunition.

Americans have an affinity for anything .30-caliber, so it was a foregone conclusion a .30-caliber cartridge for ARs would eventually make an appearance. Actually, several .30-caliber AR cartridges have burst onto the scene recently, including the .300 Blackout, 7.62X40mm Wilson Tactical, and .30 Remington AR.

The .300 Blackout and 7.62X40mm WT both are based on 5.56 NATO brass and are loaded with a variety of bullets suited to a variety of tasks. The concept is an old one and was standardized to a degree by J.D. Jones, of SSK Industries, who used .221 Fireball brass and trademarked the .300 Whisper.

The Blackout and Whisper are interchangeable to a degree, with Blackout rounds firing safely in Whisper chambers. In short-barreled PDWs (personal defense weapons) the .30-caliber bullet is much more effective than either 5.56 or 9 mm bullets. When fired through 16-inch barrels, the cartridges make fine hunting rounds, with minimal recoil and reasonable trajectories out to 200 yards.

A cartridge originally built for SOCOM/JSOC units, the Blackout is also loaded with 208- and 220-grain bullets that never break the sound barrier. The two vastly different bullet weights allow operators to initiate ambushes or handle sentry duty quietly, before swapping magazines to go head-to-head with AK-47s at ranges beyond 300 yards—with a rifle that has a nine-inch barrel.

In the world of AR cartridges, the .30 Remington AR is one of the few not conceived with martial aspirations. It was designed from the start by Remington engineers as a hunting cartridge, a way to fit .308 Winchester performance into an AR-15 and avoid the less svelte AR-10. This round essentially picks up where the 6.8mm SPC left off, able to achieve around 2,750 fps with 123- and 125-grain bullets from 22-inch barrels. The cartridge is a handloader’s dream and a favorite of this edition’s editor. In fact, Richard Mann puts the .30 RAR in a class by itself, deeming it one of the best AR hunting cartridges extant.

4 thoughts on “Advances in AR-15 Ammo

  1. capta45capta45

    “Slower 1:7 twist rates” – quite certain you meant either ‘slower velocity bullet’ or ‘faster 1:7 twist rates’. Obviously a 1:7 twist rate is faster than a 1:9 twist rate and will produce more rotation. Longer bullets generally need a faster twist rate to properly stabilize.

  2. retired75th

    There is a concerted ongoing effort to “sell” the 5.56. An effort to get the 5.56 to do what it is not cable of doing. If the platform, such as the AR and its variants was not so versatile, the AR in 5.56 would be a dying breed. It is the flexibility of the AR and not the 5.56 that sells the firearm. This is the bottom line. If you are engaging targets at 500 to 600 yes, are you seriously going to rely on 5.56? Of course not, so why push an inadequate round, except to make money. . There is a big difference between hitting the bulls eye on a paper target at 500 yds, and killing the enemy at 500 yds. If you are hooked on the AR, which is a good weapon, and want to engage real targets at extended range at least rebarrel the weapon. No firearm is the ideal for all missions and conditions, so base weapon selection on the mission, and not hype from folks with a financial angle. And one last thing, in what states is it legal to take big game with 5.56 as the author states?

    1. 454lvr

      Texas and Oklahoma are two that I know of that allow 223 to be used for deer. Oklahoma requires a 7 round or less magazine in the 223. If the ar is of the 308 variety you can used the 20 round magazine.

  3. Harold

    If you’re sticking to .223/5.56 mm, consider rounds that use Barnes TSX copper bullets. Black Hills makes loadings in both .223 and 5.56 mm, the latter to NATO and military specs, sealed, low flash powder and all that. They also sell to us their MK262 Mod 1 that you mention.