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Field Accuracy Of The MK12 (Part 1)

The MK12 Special Purpose Rifle has been around 20 plus years now give or take and has achieved an excellent reputation for accuracy and effectiveness. I won’t go over it’s history and development here except to say it was developed as a light weight sniper rifle for special operations forces. It’s use in the GWOT went on to prove it as an excellent variant of the infinitely adaptable AR15.


Since then civilian buyers have “build” copies and nearly perfect clones of the rifle. It’s been used arguably more in the civilian world than the military world at this point since it is now no longer officially used by the military. It’s proven to be an excellent precision AR15 in every way even if it is “dated” compared to the never ending marketing to selling us lighter and lighter and more and more Gucci new models and variants with debatable improvements.

One thing I have noticed about the MK12 when it comes up in discussion is the same old subject about its effective range when it comes to accuracy. A lot of people seem to think its a 600 yard gun. Of course other people who know better will shoot them further but that doesn’t seem to make much of a dent in the never ending opinions of online commenters. So once again I decided to demonstrate what it can do and push it to its extreme limits. This will be ongoing for the next few months. So let’s get started.

My first thought was to start this off with all the usual sand bags and rests and all the stuff to replicate shooting from a bench on a range to milk accuracy. Then I decided maybe it would be better if I shot the gun at long range just like it would have been used in the field, bipods and laying prone or across a pack. If I couldn’t get results from there for whatever reason I would use a bench , rest and bags.

Shooting from prone using the ATLAS bipod and no rear sand bag, I shot the rifle out to 900 yards. Target used was the official 1,000 BR target with scoring rings. I used this instead of a steel target so we would have something to actually measure by and to show results. Ammo used was the ammo developed for the SPR. The Black hills 5.56MM MK 262 ammo with 77gr. Sierra match king bullet. I cheated a bit with the optic by not using the optic issued with MK12s. In this case to better see the target and make as precise of shots as possible, I used a NightForce 5.5x-22x. This insured enough elevation as well as magnification for long range. I will be using this optic for the further testing or this series. In this first test we are looking at the MOD 1 version of the MK12. Using the KAC fore arm, a douglas barrel in 1/7 twist and the usual ops inc muzzle break. Lower is Colt with SSA trigger. Upper is Colt and Colt BCG with all the correct parts etc. Future articles will hopefully include the MOD 0.

I caught a perfect morning to do this initial testing. It was 65 degrees with no humidity and a 6 o’clock wind that wasn’t even 5mph. After fine tuning the zero, I fired 20 rounds for “record” on a fresh target.

Target above is for final record group. It wasn’t the first attempt as I needed some time to fine tune the zero and settle in after a little practice. Since I am trying to show what it can do at it’s best, I am not bothering to show you my warm up targets since they were not shot with final zero and MK262. It’s expensive so handloads stood in till I was ready.

The group probably looks as crappy to you as it did to me when i first drove down to inspect it. So to put it into perspective I put up a human like target against it since that is what the gun was meant to be used on.

Yep, I had a couple of flyers that I can’t explain. No excuse. I’m not as good as I was a couple years ago. It happens. I’m pretty happy with this. Had my spotter been my preferred partner and I shot from some sandbags I believe I may have been able to tighten this up a bit. Hand loads or the new Federal 73grain Berger gold medal load may have tightened it further. Those will be next time perhaps. I think the Q target demonstrates the ability of the MK12 with its issue ammo in knocking down human bag guys pretty well though.

In part 2 I will take the target out to the full 1,000 yards. This was my intention for part one but I anticipated terrible mirage from heat and wind and set the target up a little short. The temp and wind never did rise to the level I thought it would though and I was trying to shoot in those perfect conditions while I had the chance instead of wasting it driving back to re set the target. Next Time… 1,000 yards and maybe beyond.

17 thoughts on “Field Accuracy Of The MK12 (Part 1)”

  1. You are right on. An A-Team that I was co-located with Al-Kut, Iraq in 2004 had two Mod. 0’s that they were using. A soldier assigned to one of the rifles said that they were getting 700m head shots and 900m torso hits.

    I have a couple of photos of the Mod. 0’s if you want them for future use.

  2. You might find interesting is that NSW start fielding free floated M4A1s to fill the gap that the lack of MK12s created. Ended up putting a 20 or 25 power optic on the guns and found that the M4s were more than adequate out to 600 yards.

  3. Jesus Shawn, don’t be so hard on yourself mate! That’s excellent shooting, and I take my hat off to you.

    I’ll be turning 57 in a couple of weeks and I can’t shoot as well as I could when I was a youngster, but I still do OK.

  4. That is rollicking good shooting at 900 yards.

    The trouble with 5.56 at that range is that those little pills are losing velocity and energy fast out at those ranges. 5.56 is good at a lot, but terminal performance at 600+ yards isn’t one of them.

    Anecdata: One Afghanistan vet I knew claimed to have shot a guy in the throat with his rifle somewhere out at that range and the dude got up and ran for cover.

    One point that Kirk used to make over at Kevin’s place was that soldiers just shouldn’t have to use their assault rifles out that far. At that range, it’s time to call for artillery, air support, or get one of his beloved machine guns to lay down a beaten zone that nobody is going to walk away from. Interesting point.

    • Would you be ok with getting shot at 900 yards with a 77 grain 556 round?

      i think people get tied up over this idea that some how being hit and penetrated by 556 rounds at long range is no big deal and people just shake them off like a bee sting,
      I’d submit to you that if I was peppering all your friends with 556 rounds at 900 yards, you damn sure wouldnt be eager to get closer

      • Yeah, no sane person would sign up to get shot with anything at any range. But if my choices were to get shot at 900 yards with a .22 LR, a 5.56 or a 7.62, I know what order I’d put them in.

        Everything in engineering is a trade off. If the firearm in your hand is one of these precise AR-15s, and the question is, can I make hits at 900 yards, then the answer is “yes, if you’re up to it.” And if the question is, can I make head shots at 500 yards, then the answer is “yes, if you’re up to it.”

        But according to a ballistic chart I found at this website (http://www.shooterscalculator.com/ballistic-trajectory-chart.php), that 77 gr round is carrying approximately the same energy ay 600 yards as a 9mm at the muzzle. By the time you’re out at 1000, you’re down between .32 ACP and .380 ACP energy range.

        So if the question is, what’s the best gun and load selection for making consistent stops at 900 yards, this wouldn’t be my pick. No question it’s better than a Glock 17, an AK, or even a rack-grade AR, but there are just better tools for that job. A similar gun in 6.5 Grendel would be punching about like 10mm Auto at 600 yards, and like .40 S&W at 1000. (Source: sumdood http://www.65grendel.com/forum/showthread.php?1287-ballistics-chart).

        A 6.5 CM, a .308 or a .30-06 will carry even more energy to those ranges. Each of those will have other trade offs, including weight, size, capacity, ammo availability and price. And if you pick up your rifle from a guy named “Sarge,” well, all those trade offs get made for you, and griping at Sarge about it isn’t going to do you any good.

        Don’t get me wrong though: every rifleman (and pistoleer) should know the limits of himself and his firearm. At what distance and under what conditions can you consistently lay down a torso hit (or a boiler room shot on a game animal)? How about a head shot? But terminal performance of your chosen cartridge is part of that equation. There are lots of circumstances where a wounding shot at 900 yards would be worse than no shot at all.

        And I do enjoy the aspect of pushing firearms and leadings to their max. Hooray for the guys wringing our rimfire rifles and rifled slug 12 gauges, and yes, AR-15s chambered in 5.56. 😉

        • I don’t think anyone would argue with you that there are better rounds for killing a man at 1000 yards. And I sure hope I didnt seem to be making the argument that the 556 is some one shot stopper at that range. But I would be happy with a 380 hit on a man’s chest at 1000 yards if the fucker had a PKM and was trying to get closer to me to kill me. Part of the thing with the MK12/556 precision guns is they can make hits beyond what is considered the edge of their ability when it comes to terminal performance, the flip side to that is, larger rounds are often not as easy to shoot as accurately with the same speed for the vast majority of shooters. you give an average shooter at Mk12 , he or she will often hit at 600 easy, hand them a 3006 bolt gun and you will see that they often can’t make the same hits

  5. Good info
    My experience with cheap 55 gr (PMC)Ammo shooting from a bipod was that I couldn’t hit man sized steal past 500 yards. This makes me want to try again with the good Black Hills stuff.

    Sure do miss Kirk posting about German Machine Gun Tripods.

  6. Dang fine shooting! The mechanical accuracy of the Mk12 family is excellent.

    Are you going to use the “issue” optic for the later tests?

      • I understand the reason for using it here to show the best it can do. Do you think not using the issued spec sight will create an issue with demonstrating capability later on?

        • Perhaps, but I want to focus more on the gun and what It can do, so I need the optic to milk all its got

          also I just don’t have access to the original issue optic to use. unless you want to talk Howard into mailing me his!

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