Ammo Brief: 6mm ARC – Gun Digest

We take a quick look at 6mm ARC, a cartridge that’s ballistically superior to 5.56 NATO in almost every way.

The 6mm ARC (Advanced Rifle Cartridge) SAAMI cartridge (and chamber specs) was introduced in January 2020 and revised in June 2020.

Hornady ballistician Jayden Quinlan said, “The 6mm ARC began with a simple question: What can we do with today’s technology to maximize the performance of the AR-15 platform? We subsequently modeled and tested a variety of designs in different calibers until we were able to produce the most flexible cartridge possible within the limits of the AR-15 system.”

The 6mm ARC was engineered using a long, high-B.C. bullet in modern autoloading rifles. The SAAMI maximum average pressure is 52,000 psi. The twist rate should be 1:7.5 to stabilize 105- to 108-grain high-B.C. bullets and 1:7 twist to stabilize the 115-grain Berger VLD.

According to an article by Richard A. Mann on June 18, 2021, “Hornady … identified a need for an ‘unnamed’ Department of Defense entity and a concept cartridge was discussed. The entity showed extreme interest, so Hornady began development. Ultimately, the result of that collaboration is what’s now known as the commercially available 6mm ARC.”

“However, the 6mm ARC isn’t really new. In about 1975, Dr. Louis Palmisano and Ferris Pindell took the .220 Russian case, which is based on the 7.62x39mm Soviet cartridge, necked it up to 6mm (0.244 inch) and changed the shoulder angle to 30 degrees. Even though the 6mm PPC never gained SAAMI approval, it found great popularity in the bench-rest competition circuit. Most shooters made their own brass and loaded their own ammo.”

“However, note that there are several versions of the 6mm PPC. Though they’re minutely different, this results from a cartridge not having SAAMI approval. While some believe the 6mm ARC is based on the 6.5 Grendel cartridge, it’s really nothing more than yet another variation of the 6mm PPC.”

Quinlan said it delivers less felt recoil than larger short-action-based cartridges. However, it also uses modern, heavy-for-caliber 6mm bullets that provide excellent accuracy and ballistic performance at an extended range. The 6mm ARC delivers better ballistics than the 5.56 NATO with similar recoil. It delivers comparable ballistics to the .308 Winchester with 30 percent less weight on the firearm platform and ammunition.

The maximum cartridge overall length is 2.26 inches, the head diameter is 0.441 inch, and the case capacity of the 6mm ARC is 34 grains. With Hornady’s 108-grain ELD-Match, the 6 ARC drops and drifts less than any .223 Rem. bullet. The 6mm ARC is available in: 105-grain BTHP Hornady Black, 108-grain ELD Match, and 103-grain ELD-X Precision Hunter. Hornady lists reloading information for gas guns (52K max pressure) with bullets as light as a 58-grain V-Max.

6mm ARC Factory Loading Data And Factory Ballistics:

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

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