Review of the new  modular rail

As readers know, Colt Defense sent me the new 901 variant a few weeks ago called the  Colt 901M.A.R.C.. The new gun is different than the first version in that it has a modular rail.  The forearm is monolithic and free floating just like the LE901. but now gives you the ability to bolt sections of picatinny rail, where ever you like and its lighter.


The new fire arm is  very nice and slim.  I like the quad rail and have no problem with full railed guns at all. I like having it all on already.  But, this does make for a handier sleeker rifle than the original model.  The top is a solid rail for mounting optics or other sighting devices,as it should be in my opinion, not modular.  The sides and bottom is where you get your ability to mix and match.

The fore arm is machines in a way that it matches into the bottom side of the rail sections, and the holes have the helicoil. The coils take any damage or cross threading instead of the aluminum fore arm and are easier to fix in case of an oopsie.


The gun has the same QD sling points in the same places the LE901 had. Of course you can also attach a rail section and add a sling point to the rail anywhere that may suit you.  Also you can note the difference in the cooling slot on the rail.


Another difference form the LE901 is the way the bottom of the rail comes off. The older model came off just like the 6940  but also needing you to remove to screws on each side of the front of the rail.  Another large screw has replaced the detent the older model and the 6940 used.  While obviously this is not as fast, It locks up even more solid than the other system which was already super solid. You could trust this to hold a zero if you needed it to after you got it in place and screwed down. Obviously if you take it off, the zero will likely change, but that the way it is for anything if you take it apart after zeroing something on it.


Above is the front right side screw for the removal of the bottom of the monolith rail and the now familiar and excellent in my opinion, Colt folding and locking, front sight. Like the older 901, the front sight locks up unlike the older 6940s.  You can also see a closer view of the large allen head bolts used to secure the rail sections in place. The test rifle came with four rails of three different lengths. I do not know at this time if this will be factory standard or the gun will come with or less when it hits the stores. The rail sections are made to the same quality and specs of  the rest of the gun with the same milspec finish.


The lower is no different than the LE901. It has ambi controls and of course uses the conversion block that lets you use any upper or any caliber that will work on a lower meant for 5.56, or 6.8 etc.  and use any magazine that will fit and work inside the mag well the 5.56 guns use. Now with the the modular rail and modular mag well/caliber conversion,, the 901 lends itself to even more user configuration.


For the accuracy testing of this new 901, I did things a little different this time around. Instead of using the stock trigger, I replaced it with the Geissele  S3G trigger. I didn’t do this because the factory trigger was so bad, or I think it has to have some match trigger, but it was a 2 birds with 1 stone kind of thing. I will have more testing on the trigger as time goes by.  I wanted to see how it worked out in a 762 gun and to make the long range shooting a little easier on myself since I had less time to shoot due to the weather.

As I am wont to do, I started out shooting the gun at 100 yards for groups in 5 shot strings, I used Federal match ammo in 175 and 168 grain bullets, The Federal 165 grain TSX solid copper hollow point made by Barnes for hunting ( I used this load to kill the deer), Black Hills 175 grain match and my own handloads.

I set the gun up with my trusty test mule Leupold 18X target scope and used a front rest and bags. I used a bench and the caldwell BR type front rest.


Going the extra effort this time, really allowed for better groups. The front rest and bags with the match trigger tightened things up a bit from the results from the first LE901 test gun.

I shot 5 rounds of each at 100 yards, then I fired a 20 round group at 200 yards with the Black Hills match with 175 grain bullet.


No surprises here I think., As usual the Black Hills 175 is the winner of the factory match ammo I used. My hand loads being tailored to the gun do maybe a tiny bit better, but that is normal. No factory load will ever be able to do better than a hand load you tailor to the gun. I fired just enough hand load to test the rifle since I get nervous with using hand loads in a writers demo. If something were to happen, I would not want to get the blame even if it was not my ammo that did it.  had it been a gun I paid for. I would have given you more data from hand loads, I may still email Colt about using hand loads to make sure its not something they would rather I not do. So I may offer up a large variety of bullet performance at a later date.

The dots are all 1 inch dots for the 100 yard shooting, and the 200 yard dot is a little large than 2 inches. The 200 yard group  was something I am pretty proud of. A milspec non-match barrel shooting a 20 round string and keeping that tight is pretty impressive. It did take me a little over 30 minutes to shoot that string, but shooting small groups is hard work, and its even harder  when the string is long and things heat up and eye strain sets in.  I do not think i could have done much better than this though without some major changes to the bench rest set up and ammo.

Last but not least for this part of the review is the 1,000 yard accuracy testing.  I had a tough time with it this time around with the wind being strong at a certain point in the day, then dying off. I also had to fight sun then cloud cover, sun, then cloud cover. Sunlight and the lack of on a target is a huge hurtle to long range shooting few people talk about. But believe me, it makes a big difference when it is shifting.

I did have the help of my trusty steel gong to get me zeroed before I started my “record group” again this time.


Being able to shoot and get on the steel with instant feedback, is a giant help for trying to shoot a gun at 1,000 yard for accuracy in tests like this for me. It saves ammo, you get immediate feedback and you get to dope the wind before you start slinging expensive match ammo down range just to find out later you did not hit anything.

On a whim, I placed a NRA 50 yard bulls-eye target behind my  normal “bad guy” target to see what the “score” might look like. I thought this my offer a different perspective than the normal  bad guy photo. I then tacked those two against a card board Q target. I then placed a blob of bright orange dots on the chest of the bad guy to make it a little easier to see this time. The sun and clouds made it hard to see a dark target so I cheated a little and made it easier on myself.


As you can see from our notes, I fired 30 rounds,  I got 16 hits on the paper itself, and then I had 10-11 hits on the body.  I saw 10 to 11 because one hit the earlobe/cheek.  I will leave it to you to decided to give me credit for that hit or not. Once again, the center hit is pure chance, or luck if you prefer, I did not call it as a center hit and I certainly did not aim for it and expect it, But sometimes, often actually, when you shoot a fairly long string at something this size, I find you will luck one in to look like a great hit,


Above in the NRA 50 yard pistol slow fire target tacked behind the bad guy target just for the fun of seeing how It would “score.”  It may look good, but with 16 hits out of 30 rounds, maybe the score is not all that great,  the wind was very strong the day the 1,000 yard test was conducted. Also keep in mind, it is a 16 inch Milspec barrel on a battle carbine, Not a sniper rifle and not a precision rifle. nor meant to be.


Finally the Q target the paper targets had been tacked to.


Testing for the 1,000 yards was also done with my 18X Leupold test scope and the S3G trigger was installed.  I did not use the front rest shown.  Because of the weather and wind conditions, I did not try shooting the new gun to 1,200 yards like I did the original LE901. I do intend to test this one to 1,200 as soon as I can see a day  that the weather will allow it.  This is not a sniper rifle as I said, so the 1,200 yards shooting needs as close to perfect weather as I can get. Otherwise it would just be a waste of time and ammo. I will update this post as soon as I do get the 1,200 yard test done as well as make a dedicated post as well as try to soot it even further.

My helpers for the day of long range testing remarked how they noticed the difference in how the gun handled and felt form the LE901 and its weight. It may not seem like a lot, but you do feel it.  With the sleeker fore arm and lighter weight, you can handle this gun like a M4 with a heavy SOCOM barrel on it.  It certainly was easy to hike up the mountains all day and then was lively in the hands when I settled in to make my 247 yard shot on the 8 point buck.  It handles like the battle carbine it is but does not shy away from being used as a DMR if needed.


For those who see the carbine as only for fighting use, I did test some military ball ammo with the gun. The use of the gun as a fighting tool will be covered in the next post along with some Gopro footage of the gun being fired to show how little recoil it has and its ease of control. As a teaser and a fast little bit of info, I shot the 901 MARC with Lake City Ball at 450 yards at a Q target for a quick idea of how it might do, I aimed at a clear spot on the target and fired off a fast group from prone using bipods. Even with ball., the gun did very well at the middish range. I will be testing it to 500 to 800 with ball on the targets using a red dot and precision optics to work out how it will do on the longer shots in a combat role.   The 450 yard group below.


To end this part of the review I would like to post a picture of the first T&E LE901 from early 2012 along with the 901MARC as a comparison to how it has evolved and changed for those new to the 901 model.


LE901 above.  901MARC below


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