Posted by David Henry on 2022 Sep 29th
HORNADY 6MM ARC FOR COMPETITION
In the PRS world, there are many cartridges to choose from, but a few stand out. A few years ago, the 6.5 Creedmoor was the king, and high BC and speed was the goal. Then came the 6.5 PRC, which capitalized on the high BC of the 6.5 bullets with blistering high speeds. 6.5 PRC was an all-out speed demon, but with that came recoil, which made it harder to spot your shots and execute follow-up shots.
Today's top competition cartridges focus more on low recoil and quick recovery. This is great for being able to spot your shot (or if you're really on your game), maybe even your trace. Shooters not using 6.5 Creedmoor or 6.5 PRC have been leveraging 6mm Creedmoor or the short 6mm cartridges like the 6m m BR, BRA, BRX, Dasher, GT, and XC, to name a few. They all had huge pros, such as; ease of reloading and legendary accuracy. On the cons list, we have; hard-to-find brass, the need to fire form to fit a chamber, and the occasional feeding issue, though purpose-built magazines have rectified that particular issue.
More: ANALYSIS: 6MM BR NORMA and LOADING 6GT with HODGDON H4350
6mm ARC in an MDT Chassis System. MDT 6mm ARC AICS magazines.
HORNADY 6MM ARC
Then came the Hornady 6 mm ARC, or 6mm Advanced Rifle Cartridge, which Hornady developed for a member of the United States Department of Defense. The first I heard of it was in an AR-15 platform trying to stretch out the small framed AR-15 to 308 or AR-10 performance. Knowing I'm a PRS competitor, always looking for an edge, a local gunsmith reached out to me and asked if I wanted to try out this cartridge in a bolt gun. I was willing to try it, but as a skeptic, I brought my 6 GT for comparison.
More: Building a 6mm GT for CompetitionWe took the ARC to 600, 700, 800, and 1,000 yards with consistent hits on the plate- no problem. It was a windy day, and with the ARC, we held 1.5 MLS of wind and still had consistent hits on a 10-inch plate at 1,000 yards. I sat down with my rifle (the 6 GT), running a 112-grain bullet at about 3,000 feet per second. I took the shot at 1,000 yards with .75 ml of wind and had an impact. At that point, I declared my GT the winner, but that's not the end of the story.
Author with a custom 6mm ARC rifle.
The gunsmith was super knowledgeable and friendly, so I gave him my business and had him spin me up a 6 ARC barrel to do some testing. I was intrigued that I could get similar velocities from a BRX or Dasher with the 6 ARC. He was loading a ball powder that would run great through my progressive press, which was also very appealing. What is unique about the 6mm ARC is that it can push 105 grain Berger Hybrids between 2750 and 2850 feet per second which is what 6mm BR shooters are getting.
6MM ARC FACTORY AMMO
If you are looking at factory ammo, there is a pretty great selection. You can get Hornady's 105 boat tail hollow point match bullet in Hornady Black ammunition, 108 ELDMs- Hornady's Match ammunition, and 103 ELD X in their hunting ammunition.
6mm ARC will work with a .224 Valkyrie magazine but runs best in an 6mm ARC AICS style magazine from MDT.
One thing you'll notice about the ARC is that it was built around heavy-for-caliber bullets with a high twist rate. If you read the forums, you'll see that no one is getting the advertised muzzle velocity of 108 gr ELDM of 2750 fps out of their gas guns. So, what if we put it in a 26-in barrel on a bolt gun? We hit the 2750 fps with no problem with the 108 ELDM factory ammo. You can shoot and be competitive in a PRS match right out of the box. If you're unhappy with those results, let's discuss hand loading.
HANDLOADING 6MM ARC
You'll find two sets of reloading data in Hornady's load manual. One for a bolt gun, which has a little more pressure, and the other for gas guns. Ensure you're referencing the correct data for max performance in your rifle.
My preferred way to load ammo is with a progressive press like the Dylan xl750. I'm currently running Berger 105 hybrids and Leverevolution powder. (it's a lot easier to find than Varget or h4350) . Don't get me wrong; if you want max muzzle velocity 6 mm performance, you'll probably want to go with the 6 GT, 6 XC, or a 6 Creedmoor. For 99% of the matches we do, it's nice to have a low recoiling round where you can spot your impacts and recover quickly to get that next shot off, and the 6 ARC fits that bill. In regards to powder, when I started down the 6mm path, I started with a Creedmoor with about 42 grains of powder. I then progressed to the 6 GT with about 34 grains of powder and found I could get decent performance with the 6 ARC with 30 grains or less. The availability of good factory ammo and brass makes the ARC an excellent option for many shooters.
MY CUSTOM 6MM ARC BOLT ACTION RIFLE
My build started with a Zermatt Arms TL3 action with a 26-inch Douglas barrel with an MTU contour in an MDT ACC chassis (like my 6 GT) and balanced it to perfection. At that time, there were no 6 mm ARC AICS magazines, so I leaned on MDT and got their 224 Valkyrie magazines, which fed great. A little later in the game, MDT stepped up and designed a 12-round metal magazine for the 6mm ARC. When it came on the scene, you know I had to have that to run through my gun! I now have magazines with the right capacity, action with the proper bold face, and a perfectly chambered barrel. 6mm ARC is a fascinating cartridge I will be shooting for the foreseeable future!
ABOUT THE AUTHOR
I have 20+ years in the automotive industry- first managing shops in the northwest for over 13 years and now as a factory rep for Hunter Engineering. I love my family, my faith, and my firearms. I've shot competitively in the PRS southwest region for two years. I also compete in long-range AR-15 competitions at least once a month and am an avid reloader. I have written for Ballistic Magazine's 'Ballistic Best' precision rifle edition for two years. My other hobbies include photography, videography, woodworking, and knife making. You can find me on Instagram @davidinthesun