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.

More On Colt Monolithic Upper History

A couple weeks ago I did the “10 years of the Colt 6940” post and then a few days after realized I had left out some pretty neat stuff from the history of the Colt monolithic uppers. Over the last 10 years there was some other monolithic upper rifles and carbines from colt in some variants that we never saw displayed at any of the shows

This rifle length barrel and monolithic rail was very interesting. It came about right around the time the USMC was making noise about putting collapsible carbine type stocks on the M16A4. Supposedly making it the “A5” Never happened and neither did this variant. I would very much like to have had this gun but with a match barrel on it for a sort of 694X SPR precision rifle.

This is sort of a compromise of a M4 with a RAS but with the 6940 type folding front site and a piston gas system. Meh.

Above is a piston version of he Colt SCW. We did later see this side folding and collapsing stock trickle out via ebay and gunbroker etc. But so far nothing has been offered for sell as a standard or special order option. Later photos of more refined versions showed a DI gas system and a full monolithic 6940 upper. The side fold stock is pretty nifty but required a much modified bolt carrier group.

The most successful of the 694x series variants for military markets is the Colt IAR. Made up as Colt’s option for the USMC IAR rifle the Colt IAR is made up with a heat sink in the lower removable handguard and barrel more suited to full auto fire. A decent amount of uppers were sold on the civilian market,Howard has one, and some other countries use the full auto military version as IARs and even a sniper support weapon in the case of Mexico. You can see a video of friend of the website Alex, shooting his Colt IAR upper on a full auto lower below

Thoughts on Offset Red Dots

Long ago I tried an offset Mini Red Dot on and really didn’t like it. I was using the short lived TNVC el-cheapo red dot. The red dot sucked and I didn’t like how I couldn’t use the setup left handed. I really thought the MRDS type optics were junk for a while due to my experience with the TNVC red dot.

I’ve found that there have been many times I’ve tried something, disliked it, and never wanted to do it again. I find my self plenty quick to keep bad mounting something. Well I don’t want to be someone who is so set in their ways that they ignore advancements.

A military unit running ACOG 4x Scopes with offset Micro Aimpoints

An offset sight is most popular in competitions like 3 gun where speed is the key to winning. The offset red dot is run with a magnified optic to allow the user to instantly switch between them by rotating the rifle 30-45 degrees. This is much faster than trying to dial the adjustment on a 1-4 or 1-6 power scope.

I saw in increase of popularity of using an offset Micro Aimpoint. So I figured I’d give it a try. I picked up a Larue LT724 Offset Mount during a sale, and pulled a Aimpoint T-1 off a rifle to give it a try. I put it on my 5.45 upper so that I could get some good trigger time with it. I fired a couple hundred rounds with this combination.

One of the first things I noticed when I set up the combination was that thin strip of aluminum holding the optic. I have no doubt it is strong enough during normal use, but I’d be worried about it bending if the rifle were dropped on the optic.

Adding an offset optic instantly makes a firearm a little bulkier, a fair bit wider, leaves more stuff sticking out that can catch of stuff.

Shooting with the offset Aimpoint was so much better than that old cheap MRDS from back then.

There is no argument that an offset red dot is fast.

At close range, with an AR, it isn’t hard to tilt the rifle and rapidly fire shots into a torso. Something like the offset red dot really shines when you have larger more awkward guns with higher magnification scopes.

There is a story of a Police Sniper who was carrying his bolt action sniper rifle running up some stairs to get into an overwatch position when he ended up running into the bad guy in the stairwell. As he was holding the bad guy at gun point with his sniper rifle, he realized the high magnification scope was not ideal for that.

The M110 Carbines and M110K1 had offset iron sights to give the user the ability to rapidly engage close targets.

Firearms like the long range precision rifles that might get used in close distance fight are ideal for an offset or piggyback reflex sight.

For lighter or smaller carbines, with low power optics or variable optics, the utility of the offset sights becomes questionable.

Back to the shooting.

I found turning the gun to use the offset red dot reduced the recoil control a little. Not terribly so, but enough to be noticeable.

The T-1 is high enough and out enough that I was able to use it left handed with my left eye. Had to cant the gun counter clockwise and it was awkward, but it worked. I didn’t expect to be able to do that.

The offset sight was tucked in closer to the handguard. I’ve gotten use to higher mounted optics so I found when I rotated the rifle that I had to lower my head a bit for a better sight picture with the T-1. I don’t think other people would have that issue.

An odd setup by one of the High Speed Low Drag guys. Note the offset T-1 with the Nightforce 1-8X

The offset Aimpoint Micro is a rather nice setup. Downsides are the price and width it adds to the firearm. But I think it is only worth while if you are running a higher power optic in addition to needing to make precise close range shots quickly.

SCATTERED SHOTS (PART 4)

I originally planned to have the second part of the rifleman post up today but it is a holiday and I wanted to go hunt for Easter eggs. So instead i thought I would do another scattered shots, where I will show you some random things that caught my interest this week or may feature into upcoming articles.

First up is an image that has been around for a while. It was from a report on Hmong people still fighting the communists in the mountains of south east asia. The M16A1 below was carried by one of the Hmong. He had been carrying it and using it in the jungle since the Vietnam war. But yeah. only the AK is tough…

If you haven’t seen the John Wick films you are really missing out on some great shoot’em up action movies. If you have seen them I am sure you will “get it”. It, in this case, gave me a great laugh.

I don’t remember what news story I snatched this image from but I am really glad I thought to save it. Proof that every country has their own Top. Men. In this case in Africa. Nothing says elite like using your camel bak as frontal armor. Hey, water does a good job slowing down bullets so maybe he is on to something. I don’t think that is how you are supposed to wear your gas mask though.

good trigger discipline though

After the recent Kalifornia senator decided to run for POTUS, some worthy made this flag up..

A friend of the website and maker of fine facebook groups about the M1911, has shared with me this picture of his own BREN 10. Stuart has promised to write a guest article about his BREN10 so we can all look forward to that. Until then..

A certain 1980s TV show was clearly on his mind when he took this picture.

With the .gov in the state it’s in and the FBI showing itself to be the most top of the TOP. MEN. It felt like a good time to remember that time the Top Men saved the hell out of those kids in Waco, then posed by their burnt out bodies like trophies. Remember what Ronaldus Magnus said, the scariest words in the english language as “I’m from the government and I’m here to help”

Beyond the insanity of that image is the noteworthy detail that the sniper’s rifle has one of the rare LEO used Unertl 10x scopes. Which is the same model used by the USMC on the M40A1 for many years.

’nuff said.

Above is a scan or picture of a picture, taken on an old gun magazine about the then new Ruger varmint rifle in .220swift. The Unertl Target/Varmint scope being the only thing of interest. As for the author’s claim that the M77 was accurate, I never found that version of the M77 much to get excited about in the accuracy department.

I have always liked this image above. Yea, yeah its pure vintage FUDD stuff but I still have a soft spot in my heart fore the outdoor and hunting stuff from days gone by. What I like most about this is the longer you study it, the more neat little details you notice.

Have a medical emergency and can’t afford to go to the sawbones? Try this new pain relief!





This image of a rifle with silencer after heating up a bit I thought was pretty damn cool. The hog shooting must have been furious indeed.

I run across this guy’s political cartoons posted on social media pretty often. He clearly isn’t afraid to give them some edge. I did have a chuckle over this one. Don’t no one get asshurt and tattle to my mommy about it.

Last is a picture of the Knight’s Armament M110 Sniper system in all its glory with all it’s kit.

KeyMod vs M-LOK

M-LOK Left, KeyMod right

We were asked, “What are the pros and cons of M-Lok vs Keymod?”

Long ago there was no standard for attaching stuff to firearms. We use sling studs, bayonet lugs, hose clamps, bespoke custom mounts, etc.

Then came the MIL-STD-1913 Picatinny rail. And all was well. It took some time for people to move away from the weaver rail, but eventually most of the world adopted the 1913 rail. Except for Zee Germans, who as always thought they could do better. They came up with their own spec for rails, where they took the surface most likely to get damaged in use and make that the critical dimension. Thus the NATO spec rail was born.

Then people wanted smaller and slicker hand guards. Companies started milling off the rail section and offering bolt on rail sections. But each company had their own system. While the bolt spacing was somewhat standardized due to the sizing of Picatinny rail, how the rail section interfaced was not standardized. KAC, LMT, Larue, Colt, etc all had their own various rail attachments for their slick handguard.

VLTOR designed a new mounting system in 2012. Somewhat similar to the old post and slot system used in shelving, they included a taper on the mounting tab and recoil lugs. Best part is that they released the design as open source, so any company could use it for free.

Noveske and Bravo Company were early adopters and helped popularize the system. It looked like it was going to be the next standard. But then something interesting happened.

Before we get to what happened, lets talk about the other option, M-LOK.

Magpul came up with a new mounting system on their Masada and their early MOE line of accessories. They had slots cut(or molded) into the hand guards allowing accessories to be bolted to the slots. This was 2009. But this MOE slots sucked. They were inconsistent, and the backside of the slot had to be accessed to install an accessory.

In 2014, Magpul came up with a new standard, the M-LOK. M-LOK used slots where the accessory would lock in using a rotating T-Nut. M-LOK is free licensed, not open source like KeyMod. So people can made it freely, but they have to get permission from Magpul. This way Magpul ensures people don’t deviate from spec.

Wow, writing the history there took longer than I thought this article would be.

So what are the cons:

KeyMod accessories can be installed wrong. When I first mounted a KeyMod QD swivel, the next day I read about people mounting Keymod accessories backwards. I said, “How could anyone mount one of these backwards?” Then I found out that I mounted mine backwards. Doh.

Also some companies are cutting corners and making KeyMod accessories out of spec. Either missing the critical taper on the lugs, or missing recoil lugs.

As for M-LOK. M-LOK accessories protrude into the rail, so in areas with little clearances they can be an issue. Or sometimes the screws can protrude enough to touch a barrel in a narrow free float tube.

M-LOK screws protruding past the hand guard

It looked like KeyMod was winning the modular handguard war. Many were pushing it as the superior mounting system and it looked like the Army was going to adopt it for use on newer hand guards and sniper rifles.

Then we get to the interesting test. NSWC-Crane did a test between the two. They deemed M-LOK as being better.

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2017/armament/McGee19427.pdf

Overall, test and evaluation demonstrated that the M-LOKTM modular rail system surpassed the performance results achieved by other modular rail systems. In repeatability testing, M-LOKTM allowed for the repeated installation of the same accessory rail in the same location on a handguard with an average point of aim (POA) shift of 1.3 MOA, as low as one quarter the average POA shift observed by other modular rail systems. Drop test results demonstrated that M-LOKTM systems maintain securement of accessories to the handguard and sustain less damage from impact forces than some other modular rail systems. Failure load testing demonstrated that M-LOKTM systems support the highest load of all modular rail systems tested. In fact, the test equipment used to interface with 1913 accessory rails secured with the respective modular rail system across testing repeatedly failed prior to failure of the M-LOKTM attachment system. Even so, testing of the M-LOKTM systems failed at loads as high as over three times the maximum failure load of some other modular rail systems. NSWC Crane recommended to USSOCOM that the M-LOKTM modular rail system be utilized over the alternative systems tested. USSOCOM has chosen to incorporate the M-LOKTM modular rail system in acquisition efforts including the Suppressed Upper Receiver Group (SURG) and Advanced Sniper Rifle (ASR).

Since this test, interest in KeyMod has been reduced, but it is far from dead. M-LOK is gaining much more popularity.

M-LOK design of just being simple slots has allowed M-LOK mounting slots to be added to a great deal of accessories for other older firearms. Newer gun designs are able to have thin aluminum hand guards with simple slots milled in them allowing for the end user to add what ever accessories they deem fit.

Both are good, but now the consensus is that M-LOK is better.