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.

Comments on the Army SMG competition.

We had someone here comment on how wrong it was that the Army adopted a foreign weapon for the new SMG contract. So I felt like looking into some of the other submissions.

As far as I can tell, the first list was narrowed down to thirteen options. I got this list from, the article was written by S.W. Miller. It lists guns I did not see on other sources.

  • Z-5RS, Z-5P and Z-5K Sub Compact Weapons; Zenith Firearms
  • B&T MP9 Machine Guns; Trident Rifles
  • MPX Sub Compact Weapon; Sig Sauer
  • 5.5 CLT and 5.5 QV5 Sub Compact Weapon; Quarter Circle 10
  • PTR 9CS Sub Compact Weapon; PTR Industries
  • MARS-L9 Compact Suppressed Weapon; Lewis Machine & Tool Company
  • CZ Scorpion EVO 3 A1 Submachine gun; CZ-USA
  • CMMG Ultra PDW; CMMG
  • Beretta PMX Sub Compact Weapon; USA Corporation
  • Heckler and Koch Defense Inc for HK UMP9 Sub
  • Angstadt Arms Corporation for Angstadt UDP-9 Sub
  • Noveske Corporation for Noveske Sub Compact
  • CM9MM-9H-M5A; Colt’s Manufacturing Company

As I said, this list is different from others I have seen, but lets go through it anyways.

Zenith and PTR submitted guns based on the MP5
Zenith, which sources from MKE (Turkey).
If I understand correctly, PTR is all American production now.

The Quarter Circle 10, LMT, Angstadt, CMMG are AR15 based.
I haven’t found photos, but presumable the Colt and LMT offerings were also.
The Sig MPX is based of the AR15, but they have switched to a piston system.

Trident submitted the B&T MP9, a Steyr design being built by B&T.
Beretta’s PMX is a design that bought from B&T.
And the winner of the competition was the B&T APC9K PRO.

It appears that most of these guns are simple blow back design. The MP5s, the CMMG, Sig offerings are not.

After this first list, that offer was pulled, and the nub submission was:

  • Angstadt
  • B&T
  • Global Ordnance
  • Shield Arms
  • Sig
  • Trident Rifles

B&T and Trident both submitted B&T firearms. I believe that Angstadt and Shield both submitted blow back operated ARs that use Glock mags. Global Ordnance may have submitted the blow back operated Stribog.

From everything I read and saw during the first announcements I was sure the competition was being written for the Sig MPX. Since it has the same manual of arms, some parts compatibility with the AR, I expected it to be a sure win.

The majority of the original submissions were not made in the US or American companies. And almost all of the American submission were AR based. There really hasn’t been much innovation by way of pistol caliber long arms in the US. CMMG came up with a delayed blow back system for the AR, but I read that makes hollow points and various bullet designs unreliable.

B&T really must have done something right. In the recent past, they designed the P26, which was purchased by Beretta and renamed the PMX for use by the Italians. They made a double action/single action SMG called the KH9 that could use B&T or Suomi mags (like the 50 round coffin mag). They produced a model that could take the Suomi drum. This weird gun had a 22 pound first trigger pull, then a 2 pound trigger pull after that. WTF? They are making the MP9 and the USW machine pistols. Along with a lower cost SMG the GHM9. Their high end series, the APC, is available in 9mm, 45ACP, 5.56, .300AAC, and 308. They might have made more unique new designs than anyone else in the past couple of decades.

Anyways, I am curious what the official designation of this new Army SMG. It would be funny for it to be called the M4 Submachinegun. But I bet the Army is going to give it a rather high number.

Thoughts on zeroing

Having spent time in the military and working at a public range I learned that most people don’t understand zeroing sights or optics.

I always found it humorous when some of the regulars at the range would have a new rifle or new optic and invite me to come over and try their new gun. I’d fire a shot and tell them something like, “Cool rifle, but it is impacting 4 inches left for me.” The response I would get would be a coy line much like, “Well why don’t you go ahead and dial it then.”

I like to imagine that I keep all my firearms combat ready, but realistically I would never choose to use some of them in a fight. I wouldn’t grab the 10/22 for obvious reasons. While I would trust a Garand in a fight, it would be far from my first choice. One of the most critical things I think of as part of being “combat ready” would be the simple ability to hit what you are aiming at.

I like to think of the quality of a zero on a firearm as one of several states. I don’t think I’ve seen other people talk much about this, so I want to lay out what I think it.

  • Unzeroed
  • Mechanical Zero
  • Battle Sight Zero (BZO) or Reduced Range Zero
  • Fine Zero
  • True Zero (or proofed zero)

Unzeroed: The least desirable state for a firearm sights to be in. Hopefully an unzeroed firearm will impact close to where you aim, but there is no way to know with out test firing or checking the bore axis to the sights against a common index.

Mechanical Zero: The sight is centered either mechanically or optically. On something like a micrometer adjustable sight, mech zero may be obtained by counting the total number of clicks and adjusting it half way. On scope you could count clicks or use a mirror to get the crosshair centered in the tube. Centering a scope via scope adjustment may not be the same as optically centering.

Generally, one a well built firearm, mechanical zero will be close to right on. On cheaply built guns, not likely. If you have something like a rifle with a 30MOA canted base for long range shooting, the mechanical zero on the scope will deviate from a proper zero because of that.

It used that a brand new, out of the bolt, Colt AR15 or M16 generally didn’t need adjustments from mechanical zero when sighting in. But as of the last few years this no longer seems to be the case.

Battle Sight Zero (BZO) or Reduced Range Zero: There are all manner of reduced range zeroing techniques. Rarely you will see 10m zeroing targets. Often reduced range zeroing in militaries is done at 25m. For the longest time the USMC liked to use 36 yards for a reduced range zero on the M16A2/M16A4. The idea of a reduced range zero is to easily reproduce a longer range fighting zero at reduced ranged. It is easier and faster to zero at 25 meters than 300. Negligible effect from wind, easier to change and inspect targets, etc. The downside is that ANY minor error at this reduced range will be magnified at farther ranges. Say if a soldier was impacting 1 inch left at 25 meters, they might completely miss a hostile enemy at 300 meters. That could cost lives.

I consider a BZO an acceptable zero. I’ve found that with a 14.5 inch AR15 firing M855, if I impact 0.3 inches low at 25 yards, I will be right on at 300 yards. This lets me quickly and easily sight in any similar carbine at the very common distance of 25 yards. I used to have a scoped rifle where my 100 yard zero was 2.6 mils different from my 25 yard zero. I could dial up 2.6 mils and be right on at 25 yards. This allowed me to double check that zero with that gun at reduced range.

A BZO often won’t give you a perfect zero for the farther distance, but they should be close enough. The now common 50/200 zero is a good example. Zeroing at 50y or 50m isn’t going to give you a perfect dead on zero at 200, but it tends be close enough for practical work.

I would not hesitate to go into combat with a firearm that has a BZO. I would prefer a finer zero, but a BZO is functional.

Fine Zero: Simply put, a fine zero is zeroed at the range the firearm is intended to be sighted in at, and is adjusted as closely to being perfect as possible. A magnified scoped rifle might be fine zeroed at 100 yards. Something like a M16A2 or M4 Carbine with CCO would be fine zeroed at 300 meters. Often people going into combat never get the chance to fine zero and must just rely on a BZO.

Sometimes you are limited by the precision of the adjustments. As an extreme example, the leaf sight on my M203. Each click of the windage knob adjust the impact by 1.5 METERS at 200 meters. So if I fire a shot and impact 1/2 METER left of my point of aim, I can’t adjust closer than that. But a fine zero will be as accurate as precise as the sights allow.

A fine zero is preferred over a BZO as it will have removed any error from the BZO and have been tested out to the preferred sighting distance.

True Zero or Proofed Zero: You don’t tend to hear about this outside of precision shooters, longer range hunters, or snipers. People who have to shoot at multiple distances, or an unexpected longer range distance may take the extra step to true or proof their zero.

This is less about the zero, and more about the knowledge and preparation the shooter has made for long distance shooting. Truing or Proofing is finding out where exactly you will hit or the adjustment you need for the various ranges you might be shooting.

Simple example, I used to shoot 565 yards with a 4x ACOG. 565 yards is about 516 meters, so I should have been able to use the 500m mark in the ACOG. Instead, with my firearm and ammo I needed to use the 600m mark to impact where I wanted to hit. Had I only relied on the stock marking I would have always missed.

While I was in the Corps, when we shot the rifle range, we would note our true zero for each distance. Windage adjustment might change due to how we held our rifles, elevation might be slightly different as well. So one persons 500 yard zero might have been setting the rifle rear sight to 5, another might need to set their A2 rear sight to 5 plus 1 click.

You might have a great gun with an a great cartridge and your ballistic calculator spits out a hold over for some distance, but when you actually shoot that distance you may find you need a different adjustment or hold over. Accounting for that is truing or proofing your zero. With out proofing, that drop chart or BDC is just a suggestion, not a fact.

A very few ballistic calculators give the ability to put in your proofing results to calculate a corrected drop chart to ensure you will hit when you need to hit.

Not that simple, isn’t it?

Aimpoint H1 Micro, after 5 Years of use

I have always been a strong proponent of Aimpoint sights. Really, we all have been at looserounds. You cannot go wrong choosing any of the Aimpoint models that are currently available or have been previously available. When I worked for my hometown police department, I was the only officer with an Aimpoint, I carried an ML2 (purchased 2003). I never had an issue with my ML2, it just kept going strong year after year. I wrote an article for looserounds several years ago about that Aimpoint ML2 after running it on rifles for ten (10) years. ( Since then I have used several other Aimpoints Red Dot Sight (RDS) optics.

There are a lot of micro RDS optics on the market and numerous are less expensive than Aimpoint. So, I want to put this article in perspective for you.  Just like my previous article on the Aimpoint ML2, I am talking about a serious personal defense, military or law enforcement / duty use, micro RDS optic. Something you can trust your life or others lives on. While other RDS optics might serve you just as well, Aimpoint is known for its quality. Aimpoint has the quality and quantity that has served in military and law enforcement units in extreme environments for decades.

PSA 10.5 Pistol w/Aimpoint H1. ADM Mount

In October 2013 and January 2014, I purchased two Aimpoint H1 RDS optics. These Ampoint H1’s have a 4MOA dot and are currently out of production. Aimpoint still makes the H1 micro but it is only offered in a 2MOA dot. When you are testing a RDS sight over several years, it may go out of production, but there are a lot of that sight still out there. Also it gives you an idea of how current models will perform.

I put brand new batteries in the H1’s when I purchased them and set them on setting eight (8). Aimpoint states that on setting eight (8) the micro’s should run for 50,000 hours or five (5) years on the same battery. I would say this is very accurate as I have had both my Aimpoints on over the five (5) years.   

Aimpoint H1/Larue Mount/Colt 6720
Aimpoint H1/Scalarworks Mount

Now you may be thinking, I didn’t continually leave the H1’s on and I never used them in any hard use. The H1 micro’s have seen more rounds on rifles than I even know. They have been through countless training classes, schools and testing at looserounds. I have also tested the H1’s on several different mounts over the years. I have used American Defense Manufacturing (ADM) mounts, Daniel Defense mounts, LaRue Tactical Mounts and Scalarworks Mounts.  You will see these mounts throughout the pictures in the article.  Since the batteries have been on for 5-1/2 years they probably have over 55,000 hours run time on them.

H1’s on 6920 & 6720 / Larue & Scalarworks

For the past five (5) years my pair of Aimpoint H1 mico’s have been my home defense optics, on various rifles, Colt (LE6920s, AR6720s and currently LE6960). I have also run them on a few S&W M&P15-22s and currently on a Palmetto State Armory (PSA) 10.5″ AR15 Pistol.  While I have kept both H1’s on setting eight (8) the entire time I have had them, I have bumped the setting up and down during use, depending on lighting conditions.  During bright days on the range I have had to bump the setting up to eleven (11), or one louder it you know what I mean. I have also run the H1’s on lower settings to sight the optics in on other rifles.  I find that dialing down the sight while sighting in RDS optics, gives you a more accurate Point of Impact (POI) on the sight. After shooting or sighting in, I default the sights back to setting eight (8). I find that setting eight (8) is the best all around setting for most lighting situations.

S&W M&P15-22 / Aimpoint H1 ADM Mount



According to Aimpoint, the Aimpoint H1’s have a 50,000 hour battery life, (roughly Five years). Over the last 5-1/2 years the Aimpoint H1’s have stood up to every day work/use, countless range days, carbine course schools (on several different rifles), and looserounds firearms testing for articles, on the original batteries. Now that I have run them this long on the original batteries, I will change them out. I would suggest that you change out the battery every year just to be safe. I have said this before and it is always confirmed, Aimpoint is the only red dot optic I will ever use for professional or serious personal defense use. If you purchase one of the newer Aimpoint models, (i.e. PRO, M4, M4S, H1 – H2 or T1 – T2), with battery lives of 30,000 to 80,000 hours, these will last you a lifetime. There is no other optic that you can bet your life on and gives you that comfort that it will work every time you need it.       


My thoughts on the 6940

Yesterday Shawn posted about how the Colt 6940 series has been out for 10 years.

I remember reading about the 1040, seeing pictures of the prototypes, wanting a SCW, etc. But when the 6940 finally came out, I had thoughts similar to most. Why bother? Proprietary barrel, m4 profile, carbine length handguard. It seemed kinda silly. Even back then people were leaning toward longer handguards, different gas systems and barrel profiles. Colt came out with a product that didn’t match what the market was wanting.

Some years later I decided I wanted to get a factory Colt Short Barreled Rifle. The nice thing about SBR AR15s is that you can easily swap uppers to make it do what ever you want it to do. I was looking at buying a Colt 6933, when I found that I could get a Colt 6945 for far cheaper. So I did that instead. I am really glad I did.

Factory Stock Colt LE6945

I have long been a fan of the MK18MOD0 style AR15 configuration. I used similar setups long before I ever heard the name MK18. The 6945 is simply a better MK18MOD0. Lighter, with a monolithic upper and free floating barrel. Along with a folding front sight that is part of the gas block.

I really think it is one of these cases where something is better than the sum of its’ parts. Over a little time I ended up setting up the 6945 similarly to how Shawn had his 6940 set up.

I really love the simplicity and elegance of 6945. So when I got the chance I picked up the 6940 pictured above and set that up similarly as well.

It just works.