6mm ARC Ammo

6mm ARC: In Depth

Essentially, we’re spoiled for choice when it comes to AR-15 compatible cartridges. From 6.5 Grendel and .458 SOCOM to .300 AAC Blackout, .224 Valkyrie, and dozens more, the 21st century has witnessed the parade of able AR-15 ammunition choices grow ever larger. And the parade isn’t over, by any means. In fact, as recently as 2020 – the best year of our lives – one of America’s top ammo innovators delivered yet another AR-compatible cartridge in response to a US DoD (Dept. of Defense) request. The asks were similar to many that had come before: better long range performance than 7.62x51mm, less recoil, more accuracy, and, of course, make it fit in the AR-15 / M4’s action!

It turns out that Hornady had both the bullets and the case-design chops to get the job done. They went with 6mm projectiles, necked down the larger 6.5 Grendel case, and brought the neck shoulder junction further down towards the head (bottom) of the case. This enabled them to use long-for-caliber bullets designed to shoot at very long ranges. The results were impressive: supersonic out to 1,350-yds, and a 45% larger terminal performance window compared to 6.5 Grendel. Considering all this, the name they chose for the new round was perfect - 6mm ARC (Advanced Rifle Cartridge). In the few short years since its release, the 6mm ARC has seen use in specialized military units as well as in the competition shooting sports and long-range target shooting community. 

For hunting purposes, 6mm ARC excels in the predator-hunting arena, though light loads for varmint hunting are pretty common as well. For medium sized game, most opt for a 6.5 or larger projectile, though 6mm ARC is definitely up to the task with a well-placed shot. Another ARC – .22 ARC, to be specific – shares the same 6.5 Grendel parent case, and is also compatible with the AR-15 platform, though it’s geared more directly towards varmint shooting. Without a doubt, more ARCs will join the party in the near future, given the wild popularity of modern sporting rifles.

6mm ARC: Guns

ARs are the logical choice for this cartridge – most of the time. After all, 6mm ARC was designed to run through tactical gas guns. Seekins Precision and CMMG are just a few of the manufacturers supplying this demand. To get the most out of this cartridge, stick with an 18” or longer barrel, unless you’re purposefully looking for something shorter.In fact, 22” or even 24” barrels are often recommended for the longest shots. However, since this round has such fantastic terminal performance at longer ranges with these barrels, it works great in a hunting bolt gun, too. Savage and Howa both make bolt-action rifles geared towards predator hunting, and there are other bolt options geared towards target / match shooting as well. 

AR-15 Platform Rifles

  • Seekins Precision DMR
  • CMMG Resolute
  • LanTac LA-SF15

Bolt-Action Rifles

  • Savage 110 Predator
  • Howa M1500 Stalker
  • Christensen Arms MPR

Why Choose 6mm ARC?

6mm ARC pushes the limits of the AR-15 like no other cartridge; this is about as much performance as you can possibly get from the platform without moving to longer AR-10 actions. Those guns, by comparison, are heavier, more expensive to purchase and maintain, and harder to source parts for. Since it was designed to outperform 7.62x51mm, yet in the smaller AR-15 platform, you’re really getting the best of the AR-15 and AR-10 at the same time. Whether you’re shooting precision rifle matches, predator hunting, or taking a long-range tactical training course, this cartridge will perform admirably. 


  • Exceptional accuracy made possible by long-for-caliber bullets and intelligent case design.
  • More splash (clouds of dust / debris on impact) when shooting at long range – making for easier corrections.
  • Equally impressive in an AR-15 or a bolt gun.
  • Considerably less recoil than .308 Winchester / 7.62x51mm.


  • Varmint and predator hunting even at extended ranges, and even smaller deer at reasonable distances. 
  • Handloaders can use the wide variety of 6mm hunting bullets already on the market.
  • As more factory hunting loads are offered, this cartridge will show how versatile it really is.


  • Originally designed for defensive / tactical use. This round maximizes the potential of the AR-15 platform, especially at longer ranges. 

6mm ARC: Ammo Brands and Loadings

For factory loadings, Hornady all but has the market cornered. This makes sense, given their hand in the development and the relatively young age of the cartridge. The lightest offerings in the 75-gr. to 80-gr. range excel at varmint hunting, but can also pull double duty for long range shooting. 103-gr., 105-gr., and 108-gr. loads are versatile enough to hunt predators one day, then harvest medium-sized game or shoot matches the next. The longer this  cartridge sticks around, the more varied the loads will become. Even though Hornady’s existing loadings do a number of things well, the future holds a ton of promise for the 6mm ARC; more manufacturers will likely jump on the bandwagon, seeing as how this is an AR-compatible cartridge with extreme market potential.


Standard Loading

  • 108-gr. Polymer-Tip @ 2,750/fps (Hornady Match)

Bullet Types

  • Polymer-Tip - Target, hunting, tactical
  • BTHP (Boat Tail Hollow Point) - Target, hunting, tactical

Bullet Weights

  • 80-gr. - Varmint, predator hunting, target
  • 103-gr. - Target, hunting, tactical
  • 105-gr. - Target, hunting, tactical
  • 108-gr. - Target, hunting, tactical


  • 80-gr. - 2,850/fps
  • 103-gr. - 2,800/fps
  • 105-gr. - 2,800/fps
  • 108-gr. - 2,750/fps

6mm ARC: Frequently Asked Questions

Advanced Rifle Cartridge.

If you’re talking about most factory loads, then yes. 6mm ARC stays supersonic longer than .308 Win. and uses more efficient projectiles.
6mm ARC also has considerably less recoil than the larger cartridge, and uses a shorter action, making the overall package lighter.

The longer the barrel, the higher the muzzle velocity – up to a point. 6mm ARC does good work out of an 18” barrel, but those shooters interested in the longest shots should go for 22” or even 24” for optimum velocity.