Not just a coyote buster, the 6mm ARC is set to blast the venerable 7.62mm NATO cartridge out of the saddle, too.
Bailing out of the truck, we crunched through the foot-deep snow toward a small hill that crested 100 yards from the ranch road. Braced against the 6 degree temperatures and 30 mile-per-hour wind, we plodded into the wind on the way to our first set. We would be hunting with a new Hornady cartridge ideal for long-range coyote hunting, the 6mm Advanced Rifle Cartridge, or ARC as it will show up on the case headstamp.
No response on the first set, we shouldered our Noveske ARs and trudged back to the truck. We replayed the same exercise throughout the first day and most of the next, but high winds and new snow was keeping song dogs in their dens. The third day broke with clear skies and the heat wave to 9 degrees held promise.
Loading the guns again, we labored up yet another hill and into a bowl to set up within calling distance of a pack of coyotes that did nothing but howl at us the evening before. I was hunting with Neal Emery, Hornady’s Press Relations Manager. We had plenty of time to discuss the new cartridge.
This story began a month before when Neal and I sat in Hornady’s booth at SHOT Show in Las Vegas. The conversation turned to coyote hunting in mid-February in Wyoming. He didn’t give away any secrets, but dropped enough crumbs that I came to the conclusion that it would be AR-compatible and suited for coyotes.
6mm ARC Reveal
When I got to Wyoming Neal was a lot more forthcoming about the 6mm ARC. During the hours we spent together when the dogs weren’t cooperating, I learned that a notable DoD entity has adopted the 6mm ARC for combat operations as a replacement for the 7.62x51mm NATO, or .308 in civilian terms. You might wonder why military units would want to field a .243 caliber battle rifle, but when you get down in the weeds on the specifics of this cartridge it’ll start to make sense.
The 6mm ARC’s parent case is the 6.5 Grendel, which takes its lineage from the .220 Russian and 7.62mm Soviet. Since Hornady was the first American company to get behind the 6.5 Grendel in a big way, it was an easy transition to the new round with slight modifications to existing loading machines. The 6mm ARC’s lineage through a Soviet military cartridge gives the new cartridge quite a bit of credibility, too, as the basis for a new military round.
The 6mm ARC case head measures 0.440, just 0.005 smaller than a 7.63×39 case. A loaded round’s overall length is 2.26 inches, which fits nicely within a STANAG AR15 magazine. A 6.5 Grendel follower is all that’s needed to feed the cartridge in an AR platform rifle.
Deviating from Soviet design, the ARC takes on a 30 degree shoulder angle that’s common with other American cartridges. The ARC also has less case taper than the Soviet case.
Some of the benefits of the ARC case design is that its non-rebated rim feeds well in detachable and internal box magazines. The cartridge and chamber, by Hornady’s own admission, was designed concurrently. It uses the same design method as the 6.5 Creedmoor, which results in excellent and consistent accuracy from one gun to another, load to load. The optimal twist rate for long bullets in the 6mm ARC is 1:7.5 inches.
Performance Comparison
Reviewing the ballistics comparison between the 6mm ARC and a few .308 loads it is evident the smaller cartridge provides some advantages. The ARC firing a 108-grain ELD-Match bullet with a .356 G1 ballistic coefficient at 2,750 fps muzzle velocity stays supersonic to 1,150 yards at standard atmosphere. Fired from the same length barrel, 24 inches, a .308 178-grain boat-tail hollow-point with comparable BC and a muzzle velocity of 2,600 fps goes subsonic just beyond 1,000 yards. Other 175- to 178-grain .308 bullets go subsonic at shorter ranges. Simply put, the 6mm ARC shoots flatter, farther than what could be considered long-range .308 bullets. And, it does it from a weapon platform that weighs a third less. Carrying more rounds for the same weight burden is another benefit.
Makin’ the Fur Fly
The first set on day three we set out an electronic caller and got comfortable. Within a minute the pack we tuned up the evening before answered. At the 15 minute mark we had dogs howling in five different directions, and from the sound of it, all about a mile distant. I guess that all those coyotes had their butts frozen to the ground, since they did nothing more than howl in the distance.
We moved a couple of miles, a short distance relative to the 60,000 acres we had to hunt on the ranch. Parking where the road dipped down into a wash to hide the truck, we trekked across the snow until we hit a reverse slope to set up. More than a thousand yards ahead a high hill rose from the valley floor, so we had good visibility for a long way. Less than three minutes of calling produced a coyote loping down the hill and heading in our direction.
By the time the song dog had closed to 500 yards two other coyotes could be seen in various directions making their way to the call. When the lead dog popped up he was a scant 47 yards away and to my right. I was slightly handcuffed and slowly pivoted, and just as I got him in the scope Neal put the coyote in a pile. We both shifted our attention to the other coyotes, who were now heading for the next Zip Code. Try as I might I didn’t connect, but I knew that I was altering the coyote’s line of flight with every shot out to 1,100 yards. One of the things that I noticed immediately was that the cartridge’s slight recoil meant that sight recovery was immediate and crosshair movement was virtually nil.
The third set of the morning put us in contact with a call-shy coyote. I picked up movement about 900 yards out five minutes into the set. He continued to close the distance until he got to 400 yards. At that point, I could barely pick him out over a rise in the terrain. He just sat down to monitor the situation for several minutes, and then just melted away.
By the time we neared our fourth set of the morning it was almost noon. Our guide, Cody, spied two sets of fresh coyote tracks along the two-track just as we entered a wide valley that joined the other long valley we had hunted all morning long. He spun his truck around and we backtracked to get behind a high hill that would provide a good vantage point and calling location.
Eat or hunt was the next decision, but it wasn’t too hard. The weather was great and dogs were finally responding to the call. We had a long walk up a steep hill, so we started the ascent with me and my low-altitude-loving lungs pulling up the rear.
Just as we reached the top, Cody ducked down and motioned for us to do the same. He whispered that two coyotes were lying asleep in the valley below. I quickly got in position, the near dog snoring 188 yards away. Neal got on his gun and put the other coyote at 197 yards in his crosshairs. At the shot, the 108-grain ELD-Match bullet continued the big female’s slumber… permanently. The other coyote went from snooze mode to Mach 3 instantly, and screwed up any chance for connecting.
After lunch we resumed the hunt. We set up and before starting to call, Cody found another sleeping coyote more than 900 yards distant. Rabbit squeals from the caller woke him and started the big male in our direction. He worked his way to 248 yards and he sat down to see what was up. I muffed the shot when I didn’t get a good sight picture in the canted scope owing to a poor shooting position. Now, we were working to connect with a moving target. A miss apiece at the running coyote, we both got the coyote dialed in at 378 yards and broke shots at the same instant. The coyote rolled and we shared a kill, not knowing who connected.
A short while later, we found a bare slide, devoid of snow, and spotted for each other while we took shots at between 750 and 888 yards. Three-shot groups stayed sub-MOA with ease.
Initially, Hornady’s 6mm ARC will be loaded with 108-grain ELD Match bullets. These pills will achieve 2,750 fps from a 24-inch test barrel. The hunting load is the 103-grain ELD-X in Hornady’s Precision Hunter line. This load will top 2,800 fps in a 24-inch barrel. Mum’s the word on the 6mm ARC military load as this goes to press. Shot from the Noveske ARs we carried on the hunt, the ARC’s 108-grain ELD Match left the 16-inch barrel at 2,460 fps for comparison. Check current factory ammo prices and availability at Brownells.
This cartridge not only presents military capabilities, it will work well for law enforcement and hunting applications, too. With the support of military ammo contracts, the cost of factory ammo should be attractive to shooters. This is a cartridge that promises to be good for a micro-sized bolt-action, and I plan on building one as soon as I can get my hands on a chamber reamer. Check 6mm ARC rifle prices and availability at Guns.com.
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