Big Claims of Small Groups

AllTerra’s 1/4-MOA Guarantee Put to the Test

With all of today’s advancements in bullets, propellants, factory ammunition and the accumulated knowledge of knowing how to build accurate rifles, it’s no longer uncommon for some semi-production and custom-gun companies to guarantee 1/2-minute-of-angle accuracy, assuming the use of either premium factory ammo or prescribed handloads. But even then it’s still quite a risk for a number of reasons. For one, a lot of folks aren’t capable of shooting 1/2 MOA even with a 1/8-MOA rifle in their hands.

Then there’s range conditions, which are never so benign as to not affect group size to some degree. Every maker I’m familiar with offering a 1/2-MOA guarantee has an enclosed or underground range where there is no wind and no mirage to contend with, and the shooting is done from a concrete bench as stable as Gibraltar with a 20-pound micro-adjustable tripod with proper-fitting sandbags. And then there’s the scope…is it of high-enough magnification with a fine-enough reticle with zero parallax sitting in a stress-free mount system? Bottom line: it takes a lot of confidence in both the rifle and the person shooting it to guarantee 1/2-MOA accuracy.

But forget all that. We now have a company going by the name of AllTerra Arms based in Boise, Idaho, that is guaranteeing 1/4 MOA using their custom ammunition, and 1/2 MOA with premium factory ammo. I should point out here that the guys who specialize in building benchrest rifles, whether they offer a guarantee or not, if their guns don’t shoot at least 1/4 MOA then they’re not in business very long. But AllTerra is offering 1/4 MOA from its hunting rifles, which as far as I know, is an industry first. And it’s not just a guarantee of accuracy — if after 90 days the rifle does not meet the customer’s every expectation, it can be returned for a full refund!

AllTerra was founded in 2015 by Drew Foster, a guy obsessed with accuracy and disappointed with what he was getting from the rifles he owned, many of which were quite pricey. For what was to become his Convergence bolt action, on which all his rifles are based, Drew was awarded three patents, one covering bolt-to-bore alignment, one for no-fail cycling and another for a dual lock barrel-seating system.

The example sent us for evaluation was the Mountain Shadow Steel chambered in 6.5 PRC, Precision Rifle Cartridge, which is essentially AllTerra’s version of a mountain rifle. It comes standard with a 22-inch spiral-fluted barrel, muzzle brake and weighs-in starting at around 6 1/2 pounds depending on caliber. The Mountain Shadow Carbon is essentially the same model but with a carbon fiber barrel, which is also braked and is about a half pound lighter. Both models share the same proprietary Carbon Hunter stock that comes in several camo patterns and colors. The same with metal finishes: there are eight Cerakote color options. Our test gun wore a tungsten metal finish and came range-ready with a pre-mounted Zeiss Conquest 3-18×50 scope sitting in Talley integral-base rings. Talk about a bad-ass rig!

Other than a very attractive ALLTERRA logo machined into the left side of the receiver, there’s nothing distinctive in the outward appearance of this rifle. Nor is there anything distinctive about the barreled action once it’s pulled from the stock. In fact, it looks remarkably Remington 700-like. The receiver is a straight cylinder, but what appears to be a separate washer-type recoil lug like on a 700, isn’t; it’s integral, but the machining procedures are such that the receiver OD is about .004 inch larger than the lug diameter making it look like a separate component. It’s the same with the bolt handle: there’s an almost imperceptible annular line at the base of the handle making it look like it’s collared onto the bolt body, but it too is integral, not a separate component. Having an integral recoil lug and bolt handle are highly desirable features.

The bolt itself is distinctive only in that it is deeply spiral fluted, which reduces friction and the tendency to bind. Even when bone dry the bolt travel was very smooth, and with a little lubricant it was silky. The handle itself is skeletonized to save weight, and it looks cool. Lock-up is achieved via two massive lugs at the head of the recessed bolt face from which not one, but two plunger ejectors protrude. Such redundancy literally guarantees foolproof ejection. Extraction is courtesy of an M-16-type extractor.

What can’t be seen is the precision with which the receiver, bolt and barrel are EDM-machined and aligned to incredible .0005-inch tolerances, and chambers are cut to within .0001-inch of concentric axial tolerance to the bore. What it all means is that the receiver, bolt and chamber are perfectly aligned and concentric with the bore. As evidence of all this precision, on our test gun the rear or bearing surfaces of both locking lugs were totally burnished, indicating 100 percent contact with their abutments. That’s pretty rare even with twin-lug systems, much less with multi-lug actions.

A Remington 700-type trigger by TriggerTech is the fire control system, and the standard issue is that company’s Primary model factory-set at 2 pounds. However, five other added-cost trigger options are offered, two more by TriggerTech, and three Timneys. Our test gun came with TriggerTech’s Diamond unit which adds $145 to the rifle’s basic price of $5,495. It features a 2-position side safety that blocks trigger movement but does not lock the bolt. The bolt stop/release is an unobtrusive lever at the left side of the receiver bridge.

The stock is comprised of six layers of hand-laid carbon fiber, which results in an extremely stiff bed for the barreled action. The full length of the receiver and about 1 inch of the chamber area of the barrel are glass bedded. From that point forward the barrel is free floated. If there is one distinctive feature about the stock it’s that the comb rises from front to back. In other words, the point of the comb is lower to the bore line than at the heel of the butt. The higher the butt to the bore line, the more straight back the recoil force, which means less muzzle jump.

The standard bottom metal unit is a one-piece non-ferrous CNC-machined affair with a straddle-style hinged floorplate. Like the receiver, it’s fully glass-bedded. Allterra’s short action, on which the 6.5 PRC is based, will accept cartridges just a hair short of 3 inches. If you prefer a detachable magazine, that’s available as an option.

For accuracy testing we were sent 40 rounds of one handload, presumably the one our test gun qualified with to earn its 1/4-MOA guarantee. We also had two boxes each of Hornady’s 143-grain ELD-X hunting load, and their 147-grain ELD-X Match load.

To say I had high expectations would be understatement. Range conditions were fairly good at the outset — 62 degrees with a 4-6 mph wind, but it was pretty much parallel and fairly steady, so I didn’t think it would be a big factor. Starting with the ELD-X hunting load, my first 3-shot group confirmed that the gun had been zeroed dead-on at 100 yards, as all three shots were inside a 1 1/4-inch black circle. Wanting to give the gun every chance to show its stuff, I let the barrel cool about six minutes between groups. The barrel never got more than mildly warm to the touch. I was disappointed in that the next four 3-shot groups averaged 1.28 inches discounting one flier that was my fault. That’s fine accuracy for a hunting rifle, but I expected more. However, the fact that this rifle just didn’t like Hornady’s ELD-X Hunting load was no big thing; every rifle is unique. You just have to find out what they do like. But things were about to change…radically!

Next up was the 147-grain ELD-Match load. My first 3-shot group measured .410-inch, so it met its 1/2-MOA guarantee right out of the chute. The next group was even better, measuring .380! Those two were the best out of five groups. Averaged out, the aggregate for 15 shots was .535. That, sports fans, is superb accuracy for factory ammo!

The two best groups with the custom handload that came with the gun measured .240 and .295, with a 15-shot aggregate of .330 inch! So yes, this gun met AllTerra’s accuracy claims, and I’m not a competitive benchrest-caliber shooter, nor were the range conditions perfect. Without question this was one of the most accurate hunting rifles I’ve ever tested, and I’ve been doing this for 52 years.

However, this kind of accuracy does not come cheap. I already mentioned that the base price of the AllTerra Mountain Shadow Steel is $5,495. Add to that $195 for special camo, $70 for a foreend pic rail, which I removed because it interfered with the sandbag, and $1,750 for custom load development and 40 rounds of ammo, and you’re looking at $7,510. Judging from the number of successful hunters appearing on the company’s website, finding customers has not been a problem!–Jon R. Sundra