Ammunition

6mm ARC — Thoughts of Cartridge Infidelity

6mm ARC cartridge case stuck in the wood platform of the shooting trailer

Many moons ago I fell in love with the diminutive, yet effective, 6.5 Grendel. I had picked up a varmint-weight CZ 527 chambered for it, dropped the barreled action into a Bell & Carlson aramid composite stock, paired it with my favorite Nightforce scope, and we were off to the races. Deer, coyotes, antelope, hares, prairie dogs, and even a spike elk in the Idaho wilderness – the little Grendel became my one gun for several years. 

What always drew me to the tiny 6.5 was that its short overall length allowed it to fit into 223-sized platforms. This translates to shorter and lighter actions and less bolt travel, which in turn led to less disturbance behind the rifle. Add to that its incredibly low recoil/report, and a sufficiently flat trajectory within my typical hunting ranges, and it changed how I experienced shots on game.

6mm ARC cartridge atop a shooting bench
Fitting in the standard AR-15 platform, the 6mm ARC delivers the maximum ballistic performance possible from the smallest possible action.

Seeing and hearing impacts became the norm, something I hadn’t been getting with the .300 Win. Mag. it took the place of. I wouldn’t go so far as to say running the Grendel is like running a .22, but it’s definitely closer to that than it was to cycling the action on that magnum.

After years of faithful devotion to the Grendel, I caught word that Hornady had a new, smaller sibling waiting in the wings — the 6mm ARC

Why the 6mm ARC?

On paper, I could see that it was a Grendel killer. Flatter shooting and a tad faster, its long, thin bullets were a bit better suited to bucking wind. To be honest, it made me a little sad. I’d fallen in love with the older sibling only to find myself attracted to a younger sister with a bit longer legs and thinner waist. It was a problem.

The answer? I ignored it. I knew it was there, but I tried not to think about it, talk about it, or shoot it. It was unfortunate, really, but it was what was needed for me to keep my current rifle relationship intact. 

That all came to a crashing halt this spring when I joined friends for a prairie dog shoot in central Wyoming. They didn’t bring one 6mm ARC, not two, but four. Ugh. Custom bolt guns and gas guns… all with premium stocks and chassis, quality optics, and plenty of Hornady ammo to chew on.

6mm ARC Match in front of Hornady ammunition boxes
As much as I tried to resist, the small but mighty 6mm ARC unseated the 6.5 Grendel as my short-action cartridge of choice.

Test Firing

When no one was looking, I set up one of Seth’s custom bolt guns and started schwacking dogs in the 200 to 300-yard range with surprisingly little effort. Built on a Zermätt Origin with a heavy target barrel and big two-port brake, recoil was nearly non-existent. Add to that the clarity of the Vortex LHT and a real looker of a Manners stock, and I was rather smitten.

From over my shoulder, Kelly started calling out barkers and their ranges. The little ARC did its work. Before I knew it, I had filled the table with empty shell boxes and the field with parts and pieces. 

“How’s the barrel?” Kelly asked.

custom bolt-action rifle chambered in 6mm ARC
Stealing away with a buddy’s custom rifle, I put my first ARC rounds downrange.

Putting hand to chamber, I could feel it starting to radiate a bit of heat.

“Warm, but not hot. I needed to take a breather, though.”

6mm ARC vs. 6.5 Grendel infographic

Stepping back from the shooting bench, I knew I was in trouble. The proverbial goose was cooked. While I could never bring myself to sell my faithful little 6.5 Grendel, it was destined to start gathering dust. 

As we settled into some lunch on the Wyoming prairie, Seth could see me mulling over the problem. Stealthy as I had thought I had been, he obviously caught wind of my little fling. 

Proof Research barrel on a prairie dog gun chambered in 6mm ARC
Even with a much-abused bore, Seth’s race gun was the favorite of the shoot with its meaty Proof barrel and massive brake.

“Wait until you try my race gun, ha-ha! I’ve been running it in PRS, and the bore is pretty bad but it’s still shooting really well. I’ve got a new barrel ready to go on when we get home, so give it hell.”

And boy did we! A few of us took turns behind the rifle. Similar to the Origin, but this one with an even heavier Proof stainless barrel, four port brake and a massive, crystal-clear Razor Gen III. It quickly became the group favorite, to the point that we needed to start poking out to over 400 yards to find dogs in the previously jam-packed town. Fortunately, the 6mm ARC has a flatter trajectory. The 6mm ARC has an advantage over the 6.5 Grendel to the tune of a tad over 3 inches at 400 yards.

A week later, I’m back home and still dreaming of my own ARC. Perusing the Zermätt website, top of my list is its SR3 with right bolt/left port. My gun room already hosts a few cases of ammo loaded with Hornady 108s. I also pinged an old friend who built a set of rifles on the wonderful little CZ 527 action, back when Hornady was developing the load, to see whether he still had any gathering dust on a shelf somewhere. It should be arriving at my FFL shortly…

I know I should feel bad, but my Grendel had a great run. It’s not her, it’s me.

Are you a 6mm fan? Do you shoot long range? How would the 6mm ARC fit in your cartridge lineup? Share your answers in the Comment section.

  • 6mm ARC Match in front of Hornady ammunition boxes
  • three hunters standing around a 6mm ARC chambered rifle
  • Proof Research barrel on a prairie dog gun chambered in 6mm ARC
  • 6mm ARC cartridge case stuck in the wood platform of the shooting trailer
  • Prairie dog shooting bench mounted in the back of a trailer
  • Drone view of the Wyoming Prairie
  • custom bolt-action rifle chambered in 6mm ARC
  • cattle and sheep ranch outside Casper, Wyoming, prairie dog mounds stretched as far as the eye could see
  • 6mm ARC cartridge atop a shooting bench
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Comments (12)

  1. @grumpy… the .243 Rem is a dang good round. I actually like it. What I found years ago with some POS Rossi break action my stepson’s GF had that they bought new and she was horribly disappointed with… which of course I asked WHY the hell did you by a Rossi? Point is… the Remington factory cartridges have always been known for hard primers and that Rossi couldn’t detonate but two out of twenty rounds. But it sure enough fired all twenty of the Federal cartridges, first time, everytime. Not sure what he or she ever did with that thing… probably got sent it back to Brazil or something. Who knows. I think it had crappy manufacturing tolerences and my stepson and her dry fired the crap out it with no snap caps just on an empty chamber. Doesn’t matter now but the .243 Rem actually is a good round.

  2. Smacking praire dogs. Thanks Hornady. You couldn’t come up with anything better than than the .17HMR? That’s a hard hitting round, when it needs to be. Why are all you guys using AR style for this? Oh that’s right… it’s cool. Sheesh. Try using the .17HMR in a bolt action Marlin 917V with only a 7 round mag for the ranchers in Colorado.

  3. As an FYI to JACK, I had a Remington 788 in 6mm. Using 90 gr SPEER SP bullets and 43 1/2 grains of 4350 powder, consistently got 3 shots where the bullets overlapped at 100 yards – nice Cloverleaf groups. Some #)^ stole it, and never found it’s equal. Seems that the new generation 6mm cartridges will have a high standard to match. As stated in my prior post, still wonder how much improvement to the 6mm Remington cartridge could be achieved with modern bullets and powders.

  4. Very funny delivery! I wish they’d given you a higher word cap for this article. I think I’ll stick with my old new sweetheart, the 6.5 Grendel, in a sporter stock, for walkin’ around, general purposes. I can see a 6mm PPC or ARC for your p’dog hunting but we all have to make our own choices and live with the consequences.
    Thanks for the laughs & the insights.
    DOUG out

  5. Curious as to how the ARC, Grendel, and 6.5 Creedmore compare. I’ve been planning on a Creedmore for several years for 500+ yards as a challenge to myself. Can you do a side-by-side at extended ranges to pick the best?

  6. Very interesting article about the 6mm ARC. I’m not familiar with the 6.5 Grendel either but I’m going to do more research for certain. I have a dumb question though. Is the 6.5 Grendel in the same league as the 6.5 Creedmoor?
    Thanks for your time
    Cheers

  7. I recently put together a 6mm Remington 600 with a 700 NOS target barrel I found cheap on-line. The extra velocity makes it better than a .243 and the normal 5 shot group is a nickel at 200 yards with the right ammo. Great for the club turkey shoot. The .244 was not a mistake, just rifled and marketed wrong. The .244 was built with the wrong twist for heavier rounds, leading to faint praise and poor sales. The 6mm corrected that problem, but it could not overcome the bad press. My understanding is that it pushes the same bullet at the same velocity as these new rounds. I now have an extremely accurate gun for a little work and verry little money.

  8. Yes I put one together, bought the needed mags, die and Components. Shoot extremely well, First try at 300 was under 3″ for 5 shots with a lot of Mirage. Hit a 8″ steel plate 10 out of 10 at 300yds Very Happy! 300 is all we have here! Shoots Really well with Factory ammo.

  9. 6mm cartridges have always been underrated in the USA. While the .243 was somewhat successful, the .244/6mm died due to a misunderstanding of what it should be, Varmint or General Hunting (Deer) round? Wonder what new Powders and Bullets (and Twist Rates) could do if used in either of these “Old Timer” rounds. P.S. – My wife says I have too many guns now, so to get the “bug” for another rifle so I can try the 6mm ARC would get me in too much hot water. Maybe an AR (piston, not DG) type with a 20″ barrel…

  10. That’s how I feel about the 22-250 years ago I had a Remington 788 and that was one sweet shooter. Wish I still had it.

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