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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.

10 Years Of The Colt 6940

It’s hard to believe to me now but its been ten years since the Colt 6940 came out officially for sell. It was a pretty big deal at the time because it had been a long time since Colt had come out with a new variant of the AR15. The monolithic rail and flip up front site were something colt teased for years before it got in peoples hands.

You can see the gun above has a lot in common with the final version of the 6940. The gun pictured was submitted to the military for a possible future adoption. The early versions had a much inferior sling mounting system for the rail. You can see the stud on the side of the rail at the 3 o’clock position.

Various versions of this gun was shown at SHOT shows over the next years and scuttlebutt always claimed it would be out “later this year.” That was optimistic to put it mildly.

One of the models shown along side of those was the Colt “M5” pictured below. We never saw that. Thanks God for small favors.

Around 07, word was let out that the Colt “LE1020” was about to come out. It was so sure that some distributors and dealers started taking pre-orders. The 1020 was essentially the early version of the Colt 6940Piston. It seems at the last minute it was cancelled and refunds issued. The reasons and story will have to wait for another day.

One of the curious things of the history is this tantalizing model that many wish would be brought out even to this day. The Colt 6945 it was called at the time. Though it never came out and the colt model number was resused for another model, the 10.3 inch barreled 6940.

I am sure most of you reading this will immediately see this and wonder why it was not sold. No idea. It can be ordered this way if you are a LE org or the military, but so far that’s it. You can see the older style sling stud. As I said, the 6945 name went to another gun. Which Howard, lucky bastard that he is, owns an example of. Pictured below in all its glory.

Of course it is not the only SBR 6940 based gun. There is a 11.5 inch barrel and a 15.5 inch barrel. Also there was this little gem. The Colt SCW with a side folding stock.

In 2009 the LE6940 we now know came out and of course I got one nearly immediately. I was not let down. Since then I have been a 100 percent convert on the Colt monolithic upper. I think it is a major improvement to the gun and its accuracy is outstanding.

The 6940 in its stock form with match quality ammo and an optic makes an amazing and handy small precision rifle. I used this combo to shoot crows all summer out to 300 yards. There is just something immensely fun about shooting a carbine with a high magnification precision optic.

Over the next few years I used the 6940 constantly.

A few years later the 6940P finally came out after years of waiting. Below are the DI and Piston uppers compared. It is a very nifty design. The P comes with a SOCOM profile barrel and H2 buffer along with the piston operating system.

A full look and review of the 6940Piston can be found here on the site already so I won’t cover that again.

Since then a few other versions have come out. Noticeably the 7.62×39 variants for other countries who prefer to use an inferior service round.

You may have noticed the top picture shows a version that takes an AK magazine. That has been a foreign military sold model only at this point and it’s likely to stay that way.

Most significant to the spin off monolithic upper series is of course the 308/7.62NATO carbine 901.

Now after all this time. How does the regular old DI gun shoot? Still great. The free floated barrel and the unique system that attaches the barrel is incredibly accurate for a gun with a milspec barrel. Not to say they aren’t already more accurate than most people realize, but the free float monolithic upper brings it all out with match ammo. I placed 10X optic on my 6940 and shot some groups with it at 100 yards to show a general idea of just what they are capable of .

The carbine was shot from the bench off of bags. The leupold 10X was used and the SSA match trigger were able to make shooting a breeze. Really there is not much difference in accuracy between this and my MK12.

a selection of handloads and the more high end factory ammo

“flyer” is zeroing shot not part of group

The Colt 6940 is a real classic in my opinion and I have turned a lot of people on to them. No one I know has regretted buying these excellent carbine once they get them in their hands. It is a great gun now 10 years old and going and I highly recommend them.


RRA stripped lower Cerakoted burnt bronze.
Larue MBT
Colt FDE Anodized Upper
Colt SOCOM Profile barrel cut to 10.3″
Daniel Defense MK18 RIS II
Surefire Warcomp
KAC Handstop
KAC Sights
KAC Ambi Safety
Magpul CTR with older extended pad
KAC QD End Plate
Arms Unlimited Ambi Mag Release (not shown)
PRI Gasbuster
Colt BCG
Misc Lower Parts, most likely WOA

If I were to change anything, I would change 2 things. I don’t like the Eotech, I don’t trust it. The Arms Unlimited ambi catch fit and finish is not as nice as the Norgon they copy, and it slightly binds in this lower, I’d rather be using the real thing and not the knockoff there. To a lesser extent, the Gasbuster is overkill on this. Would rather use something like a lower profile Gunfighter charging handle.

Misc Chatter, Muzzle breaks on SBRs, AR Mags, Height over bore, MGI Hydra

Last weekend I was shooting M855 out of a 8 inch barrel with a muzzle break.  Each shot I saw a muzzle flash that extended past my peripheral vision.


Recently I saw a video where someone was doing rifle pushups with an AR15.  I was going to reference that video in this comment, but I don’t recall where I saw it.

Rifle pushups involve holding the rifle and balancing your self and it on the inserted magazine while doing pushups.  So the rifle and magazine have to support your weight and you have to balance your self on that single point of contact between the rifle magazine and the ground.

Here is a video of someone performing them with an AK:

First time I saw these, I recall the person explaining them telling us how you could never do this with the flimsy AR15.  I never thought to try it.  So I got a chuckle out of seeing someone to rifle pushups with an AR.

That got me thinking about the olden days.  For so long it was known that the weak point of the AR platform was the magazines.  That is why it was known that the AUG, G36, XM8, Galil, etc were superior weapons because they had superior magazines.

I think part of this came from the mentality caused by the Assault Weapons Ban (AWB).  During the AWB we were buying beat up old mags at very high premiums.  It didn’t help that the military just loves to never throw out old mags.  I’m fairly sure that while I was in Marine Corps, my self and my peers were issued mags older than we were.  Go to the Armory and try and swap out a mag that had bent feed lips where the rounds would just spill out like a water fountain and you would be told to fix the mag your self or they would charge you for a new one.

So for so many years I remember people talking about how the AR mag was the weak spot of the gun.  I think it was around the time Magpul started making the P-Mag that people starting throwing away their old beat up mags and buying new mags and we stopped hearing that saying.

Now it seems that people want any new 5.56 rifle design to use AR mags.

Now, to add the ultimate insult to injury, groups like Definitive Arms, Texas AK designs, and Zastava setup AKs that use M16 mags:

Oh what a world we live in.

~25 rounds fired at about 10 yards, point of aim was the red dot.

I also remember critics of the AR damning it for the height of the sights over the bore.  Because of that you couldn’t get a good zero, it was unsuitable for close quarters combat, etc.



While I was writing this, I remember the MGI Hydra.

The Hydra (which I think was also sold under other brand names) had a modular lower and a quick change barrel upper.  You could buy them separately.

The upper allows for true tool less quick change of a standard AR15 barrel just by flipping two levers.

The lower is modular allowing you to replace the front section with different magwells allowing for AK mags, 9mm mags, etc.  A M14 mag well rifle was shown, but I don’t think it was ever sold to the public.

In the past, I really wanted one of these lowers.  I thought it would be an excellent host for a SBR.  Out of curiosity I looked up the price of them while I was writing this.  The extra modular magwells are $275 each.

At that price, you could buy separate lowers and a tax stamp for each one.

No wonder I’ve never seen anyone own any of these.  It would be cheaper just to have whole new guns.

But, maybe if I win the lotto, I’ll buy one anyways.

Misc Comments

I don’t have an real content for you guys today, so here are a couple of photos.

Here is a picture of a M4A1 Colt SOCOM profile barrel that has been chopped to 10.3 inches long.  You can see the medium heavy profile and the flats that are unique to the M4A1 SOCOM Profile.  The hammer was used to keep the barrel from rolling off the table.  This is the replacement barrel for that favorite SBR upper of mine where I shot out the original barrel.

I don’t know if they still do, but Geissele triggers used to come with a short pin you could slide into them to hold the disconnector in place when you were dropping the trigger assembly into a lower.  Once the trigger group is in place, installing the trigger pin would push this shorten pin out of place.  This made installing triggers much quicker and easier.

Side note, as I have been playing around with and using that Chaos Ready rear sight, the windage adjustment on it has stiffened up a little.  I think that is a good thing as it was way too easy to adjust earlier.  I will likely update my review to reflect this after the next time I use the sight.