The Centurion Modular  Rail (CMR) was first shown at SHOT 2013, and was shown installed on a Centurion Arms complete .308 build.  The rail received positive reviews from everyone who handled it, but the most common question was how long it would be until a 5.56 variant was released.  

For the past several months, I've been working with the Centurion Arms .308 Battle Rifle, and the CMR rail has quickly become one of my favorite.  The over all feel and light weight provides a great balance for the .308 platform.  

Fast forwarding to more recent times, and I'm now in a position to comment on the 5.56 CMR rails.  I have had a chance to run  drills, do several installations, as well as have a friend and fellow instructor go over them with me.   Without a doubt, these are some of the easiest, if not "THE" easiest barrel nut and rail assembly either of us have ever installed.  

The Centurion Modular Rail is first being released in 12 and 14 inch versions in both the 5.56 and .308 variants.  

The 12" rail weighs 10 7/8 oz (308g), and with the barrel nut and three installation screws is a total of 13 1/8oz (371g).  Total length is roughly 12 1/2", which is normal for most rails labeled as 12 inchers.  The reason for this is that is the length needed to cover the receiver to FSB on a rifle, which is the traditional 12"/ rifle rail.  If the CMR used an old school locking collar, the actual rail would be 12" while the collar made up the difference.  

The 14" rail weighs 11 3/4 oz (333g), and with the barrel nut and three installation screws is a total  of 14 oz (398g).  

Machine work on the rails is all extremely high quality, and the anodizing is very clean.  It is evident these rails have a lot of machine time, and for people who are unaware, machine time is what is the driving force behind the end price.  This is why you see cheap, heavy rails with sharp edges being sold for low prices.  This is not a cheap heavy rail, and it does not have sharp edges.  

The sides are blended nicely, and the lightening / cooling/ vent holes are well laid out.  Anti-rotation tabs are part of the rail, and are nice and snug on each of the forged receivers we used (3 total).  There are QD holes fore and aft on each side.  

Installation of the rail is easy, and it is entirely possible we will do another article showing the various steps.  For now, we  will just talk about it a bit.  The barrel nut is grooved, and the bolts which lock the barrel nut to the rail ensure there can be no movement once installed.  The barrel nut is tightened with an old school barrel nut wrench, the type that only has one tooth.  These are pretty cheap to pick up if you don't already have one, and don't slip off like a standard barrel nut.  The other way to do it is using a spanner wrench (the pin or hook type), which should run you under $15 for most hardware or similar stores.  Torque specs are 30-80 ft pounds, which is simple when there is no need to line up a gas tube.  

With the barrel nut installed, slide the end of the rail into place.  It may take a firm press to lock it up against the receiver, and it is normal to have a tiny space in between the two parts.  Now use a 3/32 allen head wrench and install the 3 screws.  There is no need for thread locker, but you should alternate tightening each screw and side just like you would a lug nut.  Watch your alignment on the top of the rail and your receiver, but we found everything lined up perfect ever after we took it apart a few times.

The Centurion Modular Rails will be hitting your AR15 stores this month in 12 & 14" and in 5.56 and .308.  

You may notice the second picture has a Surefire Scout Light mounted, this is a prototype of one of the mounts Centurion Arms will be releasing along with the rails. 1913 sections are also going to be coming out shortly, and none of these add one pieces use backer plates or screws.

There are also some additional items coming out for this rail series, but I'm not 100% sure what I can or can't talk about. When I get more information, and verify that I can speak freely, I'll post more info and pictures.

If you have any questions, feel free to fire away, I'll answer whatever I can.  

This space held for additional images....

I have both of those rails sitting in front of me, I would not compare them.  The CMR also has 4 QD points.  At a certain point, you need to figure how light you want to go, and how durable you need an item to be.  That this was designed by an active duty SEAL may have something to do with the extra quality, but it is also going to be more expensive due to the increased machine time.  If you get a chance to check one out and hold it in your hand, you will quickly see what I mean.  

Photoshop, thanks.  

which rail for a 14.5" middy with a shaved FSB?

The one above is a 14.5" middy with low profile gas block, and is a 14" rail.  The actual rail is slightly less than 14".  

14" Centurion Modular Rail on a 16" Centurion Arms upper receiver group.

double tap

You pay for machine time, and these rails spend a lot of time on the CNC machines, so I would guess they are not going to be cheap.  I would think at least as much as the current C4 rails, but again, I'm not sure.

I talked to Monty, and after the initial release of the 12" and 14", the other sizes will follow.  I think we are looking at a 9, 10 and 11, but I'm not sure that is carved in stone, nor do I have even a rough guess of when they would be released.  

I'm not sure this picture really answers your question, but it should give you a bit better of an idea what it looks like closer up.  You can see the amount of machine time and quality when you hold it in your hand better than these pictures, but I still think this gives a pretty good idea.  

More pictures are coming.  As always, if you right click on the picture, and select "view image", you will see a larger version.  The board downsizes pictures pretty small.  

Are they making the light mount too?



 

Yes they are.

Shown below is the Centurion Arms CMR rail, along with the CA preproduction Surefire Scout light mount and upcoming rail covers.

I think so, there is a huge difference between these and the simple extrusion / tube rails.  

Negative Ghostrider.  At least not without having it unpinned and repinned, which is something ADCO can do for you without killing the BC.  

My understanding is yes, they will. If not exactly, perhaps a few days before or a few days after the 5.56 models.  

Centurion Arms CMR Rail with black pre-production covers.  This picture shows the 1913 rail installed on the bottom with the Magpul AFG attached.    

Centurion Arms CMR extended barrel nut.

No, the rail is not going to have any cans under it.  You need a pretty large diameter rail to go that route.  

Centurion Arms CMR Rail showing the available bipod stud and 1913 sections.

Super simple setup with the Centurion CMR upper and ACOG.

Awesome photos and info Stick!

Can't wait to get mine!

Thanks.

I've had a few people ask about the 1913 section on the Centurion Arms CMR rail, and if it fits low profile. The answer is yes, it curves to blend with the rail so it remains very low profile.

BCM 14.5" with the 14" Centurion CMR Rail.

Trijicon ACOGs, Magpul lower receivers and furniture, and Centurion Arms uppers with the new CMR rail.

Well, heck. I'm flat broke. Flatter then a pancake. But I have a gun that I could slap a 14 on. Hmmm...

I know the feeling.  

Any rail gets hot, for people who shoot heavy volumes gloves become pretty mandatory.  The rail covers should do a good job as well.