AllTerra Arms’ Mountain Shadow Steel: The Lamborghini of Rifles?

AllTerra Arms is a semi-custom rifle manufacturer in my home state of Idaho that used to be known as “Axial Precision.” These guys produce some top-tier hunting rifles with 1/2 and even 1/4 MOA guarantees, and I finally got my hands on one. The Mountain Shadow Steel is one of their steel barreled options, and it happens to be the model that I’m testing. You may look at this gun and think, “Oh, another Remington 700 clone… how unfascinating.” But you would be wrong! AllTerra has applied their own twist to accurize their rifle system in unique and interesting ways. Weight will vary with the options available to you, but this Mountain Shadow Steel rifle comes in at 6.3 lbs without optic. This low weight is made possible with a light profile barrel, fluting on the bolt and barrel, and a carbon fiber stock, mainly.

Trigger warning: The following review is on a premium, and consequently, expensive hunting rifle. Please refrain from commenting about how the average man can’t afford this, Ken/Karen. Also, we don’t need to hear about what your $300 rifle is capable of, even though I’m sure it’s great.

AllTerra’s Mountain Shadow Steel model is the perfect rifle for packing long distances on your back since it weighs around 6 pounds and is accurate and reliable like no other.

The AllTerra Difference

As mentioned, AllTerra’s Rifles are not as simple as one might think. The Convergence Action that they use features some subtle, but impactful details. To begin, the interface between the action and the bolt is unique in that the lugs themselves are conical. As the bolt is locked, the lugs are pulled forward against the action and into alignment with the bore. The second unique interface between the bolt and action occurs toward the shooter, on the back end of the bolt. Here, there is a raised ring around the bolt which slides freely through the action until the bolt is cammed shut. At this point, the whole bolt is pulled forward a tiny amount, locking this ring against a corresponding surface in the action. This act of locking at the front and back of the bolt ensures proper “bolt-to-bore alignment,” and also decrease any accuracy robbing harmonics that the bolt could impart as the gun is fired.

Notice the silver ring where this bolt locks up against the action at the rear of the bolt as the lugs are cammed into the locked position.

Next, there are some interesting things going on inside of the bolt itself with the firing pin assembly. This firing pin body is larger in diameter, creating a precise fit between it and the firing pin spring that slides over the top of it. This effectively prevents snaking of the firing pin spring that is caused with sloppy tolerances, reducing friction and decreasing lock time. Another way they further reduce lock time is by making the firing pin itself, longer. Ensuring that it never leaves the firing pin hole. Fluting of the firing pin body decreases weight and inertia: all contributing to the “fastest lock time in the industry.”

Side note: lock time is the amount of time between the trigger being pulled and the firing pin striking the primer of a cartridge. The faster this time, the lower the impact of flinching, or other movement, on accuracy.

The final unique feature that I will mention is the interface between the barrel and action. The barrel has a front and rear seating ring which lock into a corresponding front and rear seating sleeve, again creating that “bolt-to-bore alignment.” Allterra boasts tolerances of 0.0005″ (five ten-thousandths of an inch!) which result in a rifle system that is guaranteed to shoot 0.5 MOA 3-shot groups with premium factory ammunition and 0.25″ 3-shot groups with their hand-loaded custom ammunition. Two additional bragging points is their claim of no significant change in accuracy when shooting different bullet weights and that their rifles will not fail to cycle in any field condition. The latter is made possible by that locking action of the bolt as the lugs are cammed into position. Until then, there is tolerance where needed that will allow debris to be scraped away by the fluted bolt.

There are other unique takes on the construction of AllTerra’s rifles that create a match-grade machine out of a reliable hunting rifle, but I’ll let you read about them on Allterra’s website HERE.

Here is a graphic that shows the front and rear seating ring on the barrel and how it interfaces with the action.


The price of the Mountain Shadow Steel rifle will vary depending on the options that you select for your build. There is an increase in price associated with the different packages that you purchase your rifle in: the first package consists of the rifle with a 1/2 MOA premium factory ammo accuracy guarantee. The second package includes a 1/2 MOA premium factory ammo accuracy guarantee plus the development of a guaranteed 1/4 MOA custom load. The most expensive package includes all of the aforementioned plus the inclusion of a programmed ballistic unit (Kestrel) to complement your rifle. The Mountain Shadow Steel product line has a base price of $5495.00 that changes based on the package you desire and with the options that you select.

My Experience

From start to finish, I felt like I was coordinating with a custom rifle builder to produce a unique rifle built for myself. AllTerra allowed me to choose my cartridge, of course, from their 13 different options available. If you are dead set on something that they don’t offer, they’ll more than likely accommodate you after a quick phone call. After deciding on 6.5 PRC for my rifle, I asked them to cut the barrel down to a length of 20″, which they did. This rifle will come standard with a 22″ barrel normally. The next step was for me to specify what rifle scope I wanted on the completed rifle. I had a 3.6-18×44 Leupold Mark 5HD with scope rings that I shipped to them for this purpose. Yes, they mount your optic to ensure that it is done correctly (more on this later… I caused myself a headache related to this) so that it meets their 1/2 MOA or 1/4 MOA guarantee. I even picked my length-of-pull on the stock and picked my Cerakote option.

Here it is, right before I messed it up by swapping the scope and rings. I even took such care to level the scope to the scope base and torque each bolt to specification with a Wheeler Torque Wrench.

At this point, I hardly felt like I was waiting on a factory rifle to be produced. It felt more like a fully custom rifle from a reputable builder. As luck would have it, the ammo shortage hit right around this time, delaying the development of a load for my rifle. After components came available again, my rifle soon arrived at the FFL I specified. Once there, I found this neat little ready-to-go hunting rifle tucked in a giant hard case with a laser-cut foam insert. It looked so good, I barely got it pried out of my gunsmith’s hands so that I could leave with it.

But, looks don’t matter if it doesn’t perform! I got it home and immediately removed the 3.6-18×44 Leupold Mark 5HD that this rifle had on it because I needed it for a different rifle review. This turned out to be a big mistake. I promptly mounted a larger, heavier, 5-25×56 Leupold Mark 5HD that I had available and went to the range.

Here I am, carefully installing the 5-25×56 Mark 5HD. Little did I know the amount of trouble I would make for myself.

My Experience at The Range

For my first trip at the range, I saw groups that averaged just outside of 1.25 MOA, both with AllTerra’s provided custom-loaded ammunition as well as with 143 grain Hornady ELD-X and 147 grain Hornady ELD-M ammunition . Wait… this is not ok.

I chose to go home and come back to the range on a different day. It was windy and I could have been having an off-day. I came back 2 weeks later and saw the same results. At this point, I knew talking to the rifle builder would probably result in them telling me that I suck at shooting since my rifle came with a proof target that they shot personally, measuring under 1/4 MOA. To prevent this, I linked up with a buddy and had him also shoot the rifle. Identical results. I called AllTerra, half upset, and they sent me a shipping label. I got the rifle back to them and after a short wait, they got in touch and said that the rifle was not shooting well when they received it and they found some issue with the alignment of the rings (which I had swapped out with the new scope). After lapping the rings and re-mounting the scope it returned to its former glory and they got it back to me.

Accuracy Testing

Now that I was reunited with my Mountain Shadow Steel rifle, I headed back to the range and proceeded to shoot the three-shot groups below. I chose to stick with three-shot groups because AllTerra’s Accuracy Guarantee specifies such. I was not able to get the exact results that AllTerra’s rifle tester produced, but they were close enough for me to think that the rifle is capable of it and I may indeed be the limiting factor. These lightweight hunting rifles are extremely finicky, and if your technique is not perfectly consistent between shots you will see this translated down-range on the target. Again, I had another shooter put some rounds down range and they also saw excellent results.

Here is the group that the guys at AllTerra shot with my Mountain Shadow Steel with their custom handloads. (0.174 MOA)
This is a group that I put down on the day I was able to accuracy test. We had these targets mounted to small wooden frames that were blowing in the wind. I’m sure that without that complicating factor, I could shrink these groups a bit more.
Here is another group from that same windy day sit-down.

After putting some time in on paper at the 100-yard range with AllTerra’s custom loads, we stretched the rifle’s legs on targets at 500, 1000, and even 1791 yards with factory Hornady 143 Grain ELD-X ammunition. That’s over a mile! The 500-yard target was all too easy to connect on, so we pushed out further. At 1,000 yards in 25 mph winds, I was able to keep center-punching the steel plate. On the mile shot, we were fighting 30 mph winds as well as the supersonic to subsonic transition of the bullet during the last bit of its flight. Even so, we got some hits on the 1 MOA target out there.


  • MSRP: $5,495.00 and up
  • Receiver
    • CNC machined pre-harden 416 stainless steel
    • Wire EDM cut raceways
    • Integral recoil lug
    • Extended length magazine for VLD bullets
    • Lengthened ejection port
  • Barrel
    • Match-grade, hand-lapped stainless steel, spiral fluted
    • 22” lightweight contour
    • 5/8”-24 threaded for suppressors
    • Includes end cap and ultralight muzzle brake
  • Bolt
    • CNC machined from one piece hardened 4140 chromoly
    • Skeletonized bolt handle and deep fluted bolt body for reduced weight
    • Ergonomic bolt handle and knob
    • Engineered firing pin designed for fast, consistent lock time
    • Dual ejectors for improved ejection angle
    • Mini M16 extractor
    • Nickel Boron coated
  • Stock
    • proprietary Carbon Hunter ultralight stock
    • Optional color patterns
    • Pillar bedded and free-floated barrel channel
    • CNC machined floorplate bottom metal
    • Extended length internal box magazine for long cartridges
    • Optional detachable box magazine available
  • Miscelaneous:
    • weight starts at 6 pounds, varies depending on options
    • TriggerTech Primary trigger set at 2 pounds with other options available
    • Cerakote finish, many colors available.
  • Available Calibers
    • 6mm creedmoor
    • 6.5 creedmoor
    • 6.5 PRC
    • 6.5 SS
    • 6.5 SST
    • 7mm Rem Mag
    • 7 SS
    • 7mm SAUM
    • 28 Nosler
    • 308 Winchester
    • 300 SS
    • 300 PRC
    • 338 SS
      • other calibers upon request
Taking the Mountain Shadow Steel out for a spin on a windy day in Iowa.

Final Thoughts

My experience with AllTerra Arms and the Mountain Shadow Steel rifle in 6.5 PRC was phenomenal. Especially since I caused my own issues with the rifle and then AllTerra was able to fix my screw up and get the rifle back to me in such a timely manner. Being able to order a rifle and receive it with a mounted optic, zero’d at 100 yards with load development done, and information for the load provided was incredible. This was the most hassle-free long-range rifle that I’ve ever been a part of building. Yes, I felt like I was a part of the process of producing the rifle because of all of the opportunities I had to tweak the build in ways that I personally desired, such as customizing my barrel length to 20 inches. The ease that I experienced in the process led me to consider the old adage of “What’s your time worth?” An incredible amount of effort, research, and stress goes into building a custom rifle if you’re like me. In the end, I had none of this and I feel like I received a custom rifle at the end of the process. Perhaps it is worth it.

In the shop: a handful of AllTerra rifles are ready to go through testing and get sent out the door to another happy customer.

AllTerra’s rifles are not for everybody and I think that their customer is very niche. That said, customers are out there, and their rifles are in demand. The proof is in the pudding. The factory is currently turning out around 20 rifles a month, each spoken for and rapid growth is expected/observed on the manufacturing side. When you buy any AllTerra rifle, you aren’t buying just the rifle; you are buying their phenomenal customer service and their outrageous guarantees that they somehow always manage to meet. Since their rifles are long-range hunting oriented, I tend to relate to the long-range hunter in that I want to know a miss in the field is on myself, not the rifle. With the 1/4 MOA guarantee, you can rest assured that the rifle is up to any task that you’ve practiced for.

Learn more about AllTerra Arms’ custom rifles HERE!

More Pictures:

Actions ready to be built into a completed rifle at AllTerra’s factory in Boise.
Barrels at AllTerra’s factory before they are chambered and threaded. I was told unofficially that they toss out 2/3 barrels due to imperfections. This is one reason their rifles boast unrivaled accuracy.
AllTerra’s rifle stocks are built with a carbon fiber shell and foam filling to keep them from sounding plastic-y. They may be light, but they are also incredibly tough.
Here is the carbon fiber that makes up the stock. Eight of these, to be exact!

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About the author: Riley Baxter is an avid and experienced hunter, shooter, outdoorsman, and he’s worked in the backcountry guiding for an outfitter. He also get’s a lot of enjoyment out of building or customizing his firearms and equipment. Check out Riley’s Instagram @Shooter300

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  • Jim September 13, 2021, 7:19 pm

    As others have noted, it is unsightly to read “trigger warning” followed by the jargon of an SJW/liberal on a website like this.

    The only trigger warning I want to read about is a new trigger system.

  • Jason Bourne September 13, 2021, 1:10 pm

    Hi Riley,
    With what one might consider extremely tight tolerances mentioned in the fitment of the bolt/firing pin etc., how well do you think this would perform in a tactical/harsh hunting condition? Would the fitment assist in protection or become a hindrance? Just curious. Also, hey it’s your article. Write it however you want and let the whiners whine lol 😉

  • Pockets September 13, 2021, 10:41 am

    I believe Townsend Whelen said, “Only accurate guns are. interesting.” I agree, and I think this gun is very interesting. I also think the caliber selection seems a bit out of the ordinaru. I wish I had the disposable in ome to buy one.

  • D. Wichner September 8, 2021, 4:58 pm

    Those locking lugs are NOT “conical”. The locking surfaces are SQUARE to the bolt body. All bolt actions cam the bolt forward during locking, that’s what the chambering cams are for. The front of the lugs may be conical (like a model 70) but that would have nothing to do with “pulling the bolt forward”. All of that, combined with the shown 100YARD groups and, the childish “trigger warning” show that this writer has equal knowledge of rifles, shooting and writing. That is to say, very little.

    • Riley Baxter September 13, 2021, 11:18 am

      You may disagree, but you are wrong. The lugs are indeed conical, even if it is to a degree that you can’t judge with your naked eye.

  • Frank September 8, 2021, 1:14 pm

    I regularly read articles about weapon systems that I can neither afford nor justify for any number of reasons. It is however, unbecoming of a professional “journalist” to begin his/her article by preemptively lambasting those who may not heap praise on the article/author’s opinions. Don’t play football or box unless you’re willing to take some hits, or as the old adage states, “if you can’t stand the heat, stay out of the kitchen”! Also, it’s the massive number of us “poor” people who pay for you to write in the first place. The Rich Boyz with their Rich Toyz seldom take time to peruse online gun articles.

    • Give Me Liberty September 11, 2021, 12:51 pm

      Well said Frank.

      If I were buying a precision long range rifle I would spend less than $2,000 and invest the additional $3,500. In seven years time I would likely have double my money and a long range rifle.

  • SuperG September 8, 2021, 9:24 am

    Wow, to minimize the opinion of others because they don’t want to sink $6000 into a rifle is not only pretentious, but it is something a Democrat would do. That kind of attitude only serves to promote an elitist mindset, and alienates the general readership. Where does it stop? What other comments should we precluded with that kind of thinking? “Sorry, but since you don’t own a SIG, your S&W comments are not welcome here”. I’m surprised the “trigger warning” was allowed.

  • Dale E BRYAN September 7, 2021, 9:31 pm

    Great read Riley !! Good content and I love the pix’s. I don’t need one where I hunt, but I like to drool over other peoples guns!! Easier to let someone else clean the slobber LOL….

    • Riley Baxter September 13, 2021, 11:20 am

      Thanks for taking it as what it is, a fun article for a gun you aren’t interested in. Some of the others that are upset about a gun that they don’t want to buy could take some notes. Their blood pressure would probably drop a few points.

  • Matt Kartozian September 7, 2021, 8:28 pm

    Love the trigger warning! Keep it the good work.

    • Riley Baxter September 13, 2021, 11:21 am

      Glad someone else also has a sense of humor!

  • Dean Gates September 7, 2021, 7:03 pm

    To spend that kind of money on a rifle you have to have more coins than brains.

  • German Olmeda September 7, 2021, 3:11 pm

    Listen Baxter, Karen and Ken have a very valid point ! Instead of reviewing absurdly expensive rifles-maid for “Millionaires ” ,that us working folks cant afford, that you would focus more on the best,more cost effective, less pricier products ! The ones we can afford ! Just saying ! Peace ! God bless America, long live the Republic, God bless our troops !😎👍✌🙏

  • Larry C September 7, 2021, 2:14 pm

    I think that this is a a boost that can be matched by any competent gunsmith without being expensive. When I worked a Shappel’s Guns in Idaho, Randy S. rebarreled and tuned one gun for me and later, I built one on a Remington action in a smaller caliber. Both guns shot and still shoot sub 1/3 minute out beyond 500 yds. The cost was substantially lower. I am not into gunsmithing any more but Randy may still be and he is more than capable of matching this expensive gun.

    • Riley Baxter September 13, 2021, 11:25 am

      I agree with you! If you have the know-how abs want to take the time and put up with the hassle of piecing together a custom gun with a gunsmith, you can end up with a great firearm. However, this product is a tweener that splits the difference between full custom job and factory rifle. You get the high end results with the option of buying a ready-to-shoot rifle.

      Not for everybody, obviously. But there is a solid customer base, as evident by AllTerra’s rapid growth.

  • Dusty September 7, 2021, 1:19 pm

    Looks like it shoots well. No comments on its handling other than from the bench. Pricey…
    Can’t say I was impressed by a rail on the fore end bottom, and really don’t care for sharp edged full length scope mount rails. (I do not care about how strong or they are- I’m not planning on dropping my rifles a lot, nor mounting scopes that weigh 20 plus ounces on them.)

  • clifford c bailey September 7, 2021, 11:35 am

    Your trigger point was a nasty dig toward people. I was offended by it, did not read the whole article. As an FFL I help people find a firearm that is right for them with considerations to budget, use of the firearm and safety. Your condescending attitude toward people by calling them (Ken/Karen) is reprehensible. I will delete Hunt 365 if you continue to be employed and write articles. And yes. I have high end buyers also!

  • Ken September 7, 2021, 10:22 am

    Once I got to the trigger warning, I realized this writer is a baby and apparently can’t handle even the slightest criticism, so he chooses to attack readers. Didn’t even read the article after that.

    • Riley Baxter September 13, 2021, 11:27 am

      Hey Ken, I just passed you going the other way on this street! Hello from the other lane!

  • Matt Morehouse September 7, 2021, 9:47 am

    I’ll take two.

  • Ron September 7, 2021, 9:04 am

    It seems like every time I read a rifle review, the author uses wind, cold, heat shimmer, etc. as a excuse why their accuracy/precision was not what they expected and then they say something like “I believe this gun is capable of better accuracy with the right load and better weather conditions”. If these “Pro’s” are going to get paid writing reviews on guns, then at least test them under near ideal conditions so the tests results are useful. The old song “It shot well, but” just does not get it.

  • Timothy J Strobel September 7, 2021, 7:36 am

    I have a light weight stainless steel Tikka in 6.5 Creedmore that will shoot 1/4 inch groups all day with handloads
    your rifle is just a lot of over priced and over engineered marvel. I have three friends with the same rifle as mine
    and they all shoot the same. The total price with 3X9 Leupold is $986.00


  • Kurt Hall September 7, 2021, 7:32 am

    The accuracy results of the author are not impressive for a $5500 rifle. All my over the counter plugs shoot a1/2″ MOA, or significantly smaller groups with after market triggers and pillar bedding.

  • Mike Prout September 7, 2021, 4:23 am

    6k. Ur funny

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