Hornady 6mm ARC Load Data for Bolt-Action Rifles: Tested

Initially proposed as the 6mm Optimum, Hornady's 6mm Advanced Rifle Cartridge (ARC) is the result of the transformation of at least five previous cartridges.

August 02, 2024 By Steve Gash

The military is always on the lookout for better armament, and this includes new cartridges that can fill many roles. Infantry magazine is published by the U.S. Army in Fort Benning, Georgia, and in a 1999 edition of the magazine an article by Stanley C. Crist (1921–1998) was printed. That article called for the development of just such a new cartridge. Crist was a former tank commander, platoon sergeant, training NCO, scout section leader, consultant, and writer, and he called his hypothetical round the 6mm Optimum. It would have more power than the 5.56mm NATO; light recoil; about the same terminal performance as the 7.62x51 NATO; and could be used in infantry rifles, machine guns, and sniper rifles. And the ammo would weigh about the same as the 5.56. The details of such a proposed round are pretty impressive. Crist said that it would launch a 100-grain 6mm bullet at a velocity of about 2,900 fps. This would produce 1,868 ft-lbs of energy at the muzzle and have modest wind deflection.

6mm-arc-load-data-02 — Hornady introduced the 6mm ARC in 2020 and currently offers three factory loads: the 103-grain ELD-X Precision Hunter, the 105-grain BTHP BLACK, and the 108-grain ELD Match.

The 6mm Advanced Rifle Cartridge (ARC), as it is now called, was introduced in 2020 by Hornady, and the development of the cartridge has an interesting and illustrative history. The 7.62x39 appeared in 1943 and was reformed into the .220 Russian (a.k.a. the 5.6x39 Vostok) in 1961. In 1972, the .220 Russian was reformed into the .22 PPC benchrest round by Dr. Louis Palmisano and Ferris Pindell. In turn, in 1987 the .22 PPC was necked up to 6mm to form the super-accurate 6mm PPC. With slight modification, the 6mm PPC was necked up to form the 6.5 Grendel in 2002. But wait, there’s more! The 6.5 Grendel (a powerful, accurate, and multidimensional round in its own right) was necked down to 6mm and modified slightly to become the 6mm ARC. So, we went from the 7.62x39 to the 5.6x39 to the .22 PPC, 6mm PPC, 6.5 Grendel, and finally to the 6mm ARC. This is an example of cartridge evolution in action, and the results are impressive.

Ballistically Speaking

I find it fascinating to compare Crist’s proposed ballistics with those of the 6mm ARC. Hornady’s results come pretty close to many of Crist’s desired performance goals. Hornady put a lot of thought into the final design of the 6mm ARC case and the bullets it shoots. The 6mm Advanced Rifle Cartridge is certainly advanced. The accuracy and uniform ballistics of the 6.5 Creedmoor are well known and are the result of the strict dimensional specifications of its case and chamber, and these criteria were applied to the 6mm ARC. The base and rim diameters of the 6mm ARC and the 6.5 Grendel are essentially the same (0.441 and 0.438 inch). The 6mm ARC’s case capacity is about 43 grains of water, and its case length is 1.490 inches, shortened slightly from the 6.5 Grendel’s 1.516 inches. Both have 30-degree shoulders. Neck lengths of about one caliber are thought to be optimal for the best ballistics and accuracy, and the 6mm ARC has a neck length of 0.234 inch (.96 caliber), compared to the Grendel’s 0.243 inch (.92 caliber). Overall cartridge length of the 6mm ARC is set at 2.26 inches, making it compatible with AR-platform magazines.

Another point emphasized by Crist was that his proposed 6mm cartridge would have better downrange performance, with less wind drift. And this was before today’s high-ballistic-coefficient bullets, but he talked about “very low drag” bullets. Another factor that optimizes the 6mm ARC round’s performance with new long and heavy-for-caliber bullets is a really fast twist, set at one turn in 7.5 inches. Plus, the new 6mm ARC is mild mannered and doesn’t kick your socks off. The free recoil of a typical rifle with representative loads is a mere 4 to 6 ft-lbs. This also contributes to great achieved accuracy. The muzzle energy of full-power 6mm ARC rounds with 100-grain bullets is about 1,600 ft-lbs. The same metric for the 5.56 NATO with a 55-grain bullet is about 1,030 ft-lbs. Plus, a soldier could carry about as many of the 6mm ARC rounds as 5.56 rounds but with an increase in muzzle energy of about 55 percent. Add this improvement in downrange ballistics and light recoil, and the many advantages of the 6mm ARC are obvious. Rifles have to have ammo to perform, and as I write this, to the best of my knowledge, only Hornady makes 6mm ARC factory loads, but they cover the varied applications of the 6mm ARC very well. For competition shooters, there is the Match load with a 108-grain ELD Match bullet at a listed 2,750 fps. For the AR, the BLACK load carries a 105-grain BTHP bullet, also listed at 2,750 fps. Then there is the new Precision Hunter load with the excellent 103-grain ELD-X bullet at 2,800 fps. The ballistic coefficients of these three bullets are eye-popping. For the ELD Match, it’s .536. For the BTHP, it’s .512. And for the ELD-X, it’s .530.

A Snap to Handload

On top of all that, the 6mm ARC case is a snap to reload, and there are scads of high-tech 6mm bullets for the hand-loader. Hornady offers cartridge cases, reloading dies, and other precision tools for the handloader. Many powders work well in the ARC, but Hodgdon LEVERevolution is a top choice. Crafting super accurate handloads is a delightful enterprise, since the little case seems to like almost every load combination, and the handloader can whip up loads for long-range varmint or target shooting or popping steel. But for me, the most interesting aspect of the new round is the extreme versatility with the myriad of bullet designs. Western rockchucks are in big trouble this fall!

Shooting Results

For this report, I was fortunate to have two high-quality and very accurate bolt-action rifles in which to evaluate 6mm ARC factory ammo and handloads. A fairly new offering from Savage is the Model 110 Carbon Predator. It has an 18-inch Proof Research carbon-fiber barrel with a 1:7.5 twist. The muzzle is threaded, and the rifle comes equipped with Weaver-type scope bases. I scoped the rifle with a Trijicon Tenmile 3-18X 44mm FFP scope. So equipped, this rifle is a mite heavy, but it shoots terrifically. The other 6mm ARC test rifle is an experimental prototype Ruger American. It has a 22-inch barrel with a 1:7.7 twist. The Americans have a well-earned reputation for accuracy, and this one certainly lived up to its reputation. I used a Leupold VX-3HD 2.5-8X 36mm scope on it. The results of all bench testing are shown in the accompanying chart, and as noted earlier, the only factory loads for the 6mm ARC are from Hornady. All were accurate. As for the handloads listed, I tested many, and the examples shown were selected as a representative cross-section of potential loads for each rifle. In the Model 110, the average of the three factory loads was a dazzling 0.52 inch, and the handloads averaged 0.68 inch. In the American, the factory loads averaged 0.72 inch, and the handloads averaged 0.84 inch. It’s easy to see that one can find a factory load or a handload for just about any shooting purpose, whether it’s formal long-range target shooting or just busting rocks in the back pasture. And in addition to the plain shooting fun with the ARC, I think one of its many virtues is its potential in the hunting fields. The Match and BLACK factory loads would surely handle varmints, as would handloads with 65-, 75-, or 80-grain bullets. These high-ballistic-coefficient bullets hold velocity and energy well, so they would certainly be adequate for smaller big game like pronghorn antelopes and Texas deer. And there are several controlled expansion bullets, too.

6mm-arc-load-data-03 — The 6mm ARC is based on a necked-down 6.5 Grendel case. The 6.5 Grendel came from the 6mm PPC, which grew out of the .22 PPC. The .22 PPC was based on the .220 Russian, which was modified from the 7.62x39. Steve tested 6mm ARC factory ammo and handloads in a Savage Model 110 Carbon Predator rifle and a prototype Ruger American rifle. As these half-inch five-shot groups at 100 yards indicate, the ammunition and rifles performed very well.

The 6mm ARC compares favorably with the classic .243 Winchester and some other rounds with big-game bullets. Using Hornady’s factory-listed ballistics, the data is listed in the accompanying chart. Almost everyone would agree that the .243 Win. with a 100-grain bullet is a perfectly adequate deer or antelope load out to 300 yards, or maybe even 400 yards. As you can see, the 6mm ARC stacks up favorably at 300 and 400 yards. Just for reference, I have taken quite a few whitetails with the .243 Win., an axis deer with the 6.8 SPC, and a 236-pound aoudad ram with the 6.5 Grendel. Looking at the numbers, it’s plain to see that the 6mm ARC would have filled such hunting roles admirably. The 6mm ARC is accurate, economical to shoot, and hits way above its weight class. It’s a neat, well-designed little round. I haven’t decided on my deer rifle this fall, but I think Hornady’s 103-grain ELD-X factory load in 6mm ARC is a great candidate and may get the nod.