Skip to main content

U.S. Military Adopts Hornady's New Cartridge: 6mm ARC

Guns & Ammo tests Hornady's new long-range precision cartridge.

Hornady’s 6mm Advanced Rifle Cartridge (ARC) is the first time in history that the commercial announcement of a cartridge was preceded by adoption within the military. While Hornady has been extremely secretive about who adopted the cartridge, they can say that it is a “notable Department of Defense (DOD) entity.”

The reasons a military unit would be interested in the 6mm ARC are for its utility and mild manners that ensure long firearm life. Threats have learned to stay 500 to 600 meters away from our troops on the battlefield to be safe from the effectiveness of our 5.56mm rifles, carbines and machine guns. The U.S. military has been looking for a solution. 

The 6mm ARC is unique among rifle cartridges in that it fits in an AR-15-pattern action, functions reliably out of standard-capacity 24- or 17-round magazines, and remains supersonic beyond 1,000 yards in a standard atmosphere. This allows a rifle chambered in this cartridge to be used for everything from close quarters battle (CQB) to sniper missions while simplifying logistics for the units that carry it.

Hornady 6mm ARC
Exceeds AR-10 308 Win. external and tactical terminal performance with 30% lighter system*
*6mm ARC Match 108-Gr. ELD: 24” BBL; .536 G1 @ 2750 FPS (STD Atmosphere)
308 Win 178-Gr. ELD-X: 24” BBL; .552 G1 @ 2600 FPS (STD Atmosphere)
(Data courtesy of Hornady)

The 6mm ARC is based on the 6.5 Grendel. Hornady started by necking down the cartridge to 6mm and then pulled the shoulder back closer to the case head .030-inch. Engineers also shortened the case to make the cartridge friendly to long low-drag bullets that have high ballistic coefficients. The 6mm ARC was designed around optimal use with a 108-grain bullet.

In addition to making the cartridge useable with long, heavy-for-caliber bullets, Hornady also set maximum chamber pressure low at 52,000 pounds per square inch. This slows extraction and makes it much less violent, prolonging the bolt’s life.

Hornady 6mm ARC
Data courtesy of Hornady

While it is unlikely that the 6mm ARC will ever see military-wide acceptance, its utility, excellent performance, and mild manners make it an ideal solution for anyone looking for a “one-and-done” cartridge chambered in an AR-15.

For more information, visit hornady.com and pick up the September 2020 copy of Guns & Ammo magazine.

Hornady 6mm ARC

Rifle: Seekins Precision DMR

  • Type: Direct impingement, semiautomatic
  • Cartridge: 6mm ARC
  • Capacity: 17 or 24 rds.
  • Barrel: 20 in.; 1:7.5-in. twist
  • Overall Length: 40.5 in.
  • Weight: 8 lbs., 9 oz.
  • Stock: Seekins ProComp 10X
  • Grip: Magpul MOE+
  • Length of Pull: 14 in.
  • Finish: Black anodized
  • Sights: None
  • Safety: Two-position selector
  • MSRP: $1,650
  • Manufacturer: Seekins Precision, 208-743-3400, seekinsprecision.com
Current Magazine Cover

Enjoy articles like this?

Subscribe to the magazine.

Get access to everything Guns & Ammo has to offer.
Subscribe to the Magazine

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Recommended Articles

Recent Videos

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Videos - Guns - Other

Ballistic Advantage Continues Excellence in Barrel Design

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Rifles

Winchester Ranger Returns! Now In .22

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Rifles

Latest Name In Lever Guns: Aero Precision

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Rifles

SAKO 90 Quest Lightweight Hunting Rifle

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Optics

Warne Scope Mounts New Red Dot Risers

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Accessories

New Warne Scope Mounts Skyline Lite Bipods

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Handguns

Smith & Wesson Response PCC: Now Taking SIG Mags

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Optics

Mark 4HD Riflescopes: The Latest Tactical Line From Leupold

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Rifles

Show Stopper: Smith & Wesson 1854 Lever-Action Rifle

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Suppressors

FN 509 Pistol Updates and New Suppressors!

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Handguns

New From Armscor: RIA 5.0E & More STK Pistols

There are many new and exciting products and companies to look for at the 2024 SHOT Show, but one in particular that sta...
Handguns

Watchtower Firearms: A Premium American Company to Watch

Guns and Ammo Magazine Covers Print and Tablet Versions

GET THE MAGAZINE Subscribe & Save

Digital Now Included!

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE

Buy Digital Single Issues

Magazine App Logo

Don't miss an issue.
Buy single digital issue for your phone or tablet.

Buy Single Digital Issue on the Guns & Ammo App

Other Magazines

See All Other Magazines

Special Interest Magazines

See All Special Interest Magazines

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Get the top Guns & Ammo stories delivered right to your inbox every week.

Phone Icon

Get Digital Access.

All Guns and Ammo subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit mymagnow.com and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now

Enjoying What You're Reading?

Get a Full Year
of Guns & Ammo
& Digital Access.

Offer only for new subscribers.

Subscribe Now