Hornady .338 ARC: Reviewed

Hornady began working on the .338 Advanced Rifle Cartridge (ARC) in 2017. The impetus for its development was a request from the U.S. Department of Defense (DoD), who was searching for a subsonic load with enhanced accuracy and terminal performance. Although the .338 ARC showed promise, its development was moved to the back burner when Hornady was called upon to focus on the 6mm ARC, introduced in 2020. Then, the .22 ARC arrived in 2024. The .22 ARC is another high velocity round with a flat trajectory.

The success of the 6mm ARC and the .22 ARC rekindled enthusiasm for the .338 ARC. Hornady learned a lot about developing subsonic cartridges. Changes to the bullet weight and geometry for the Sub-X load resulted in vastly improved performance compared to early iterations of the cartridge.

While the typical range for a subsonic rifle round might be 100 to 150 yards, the 307-­grain Sub-­X is effective beyond 200 yards! It’s a versatile option. Chamber a supersonic cartridge from Hornady’s Black line and shooters will extend their practical engagement distance. The .338 ARC gives us the option of shooting subsonic or supersonic loads, too — with or without a suppressor — from an AR-­15 on the same gas setting.

According to Hornady Marketing Communications Manager Seth Swerczek, “Running a cartridge below the speed of sound can produce some obstacles. The purpose-­built .338 ARC takes the guesswork out of it, providing consistency, accuracy and terminal performance.”

The .338 ARC is a strange looking cartridge using the 6.5 Grendel as its parent case. The bullet accounts for nearly half of the cartridge’s overall length. It’s available in the subsonic 307-­grain Sub-­X load, a 285-grain subsonic full-metal-jacket in the Frontier line, and three Hornady Black supersonic loads: 170-grain MonoFlex, 175-grain HP Match, and a 215-grain FTX. While supersonic offerings are a better option at targets far away, subsonic performance is what the sets the .338 ARC apart.

Designed for barrels with a 1-in-8-­inch twist, the 307-grain Sub-­X bullet expands reliably. It’s an excellent cartridge for deer, hogs and similarly sized game inside about 200 yards. 

“The .338 ARC really represents the pinnacle of subsonic performance,” said Swerczek. “The cartridge case produces consistent velocity, which is paramount in downrange accuracy when shooting below the speed of sound.” 

The 307-­grain Sub-­X load produces roughly the same velocity as the much lighter, 190-grain Sub-­X load for the .300 Blackout. Since the .338 ARC is so much heavier than the .300 Blackout subsonic round, it delivers considerably more energy on target, too. According to data from hornady.com, at 200 yards, the 190-grain Sub-­X bullet in the .300 Blackout produces 384 foot-pounds (ft.-lbs.) of energy. The 307-grain Sub-­X bullet in the .338 ARC produces a whopping 605 ft.-lbs. of energy, by comparison. I guess that’s why they’re calling it, “The Big Little Cartridge.”

When the 307-grain Sub-­X bullet is fired from a suppressed rifle, it is quiet. Felt recoil is light, making it fun to shoot. Not only is it a viable cartridge for hunting and defense, but it’s also a great cartridge for training new shooters. Pricing is expected to retail between $33 (Frontier) and $53 (Black) for 20 rounds. 

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