C4 Rail, Carbine Length Cutout Rail Handguard

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The Centurion patented C4 rail system is a lightweight, rugged, 2 piece free float rail that when installed gives the uppers a continuous 12o'clock rail. The C4 system is the lightest and most rigid rail that clamps to a standard barrel nut on all AR15, M4, and M16 type weapons systems. This design allows the installation of the rail on an upper assembly without removing the front sight post or permanently attached muzzle devices. **Please note that some FSBs may need to be modified to fit by filing down the longer sling attachment ears so that they are not touching the handguard

**Please Note: Current version of the rail has some slight cosmetic differences from stock photos
Engraving is now machine engraved and black anodized....no white markings.



Material: 6061 T6

Finish: type 3 hard coat anodized

Weight: 10.5oz with screws---1.1oz more with standard barrel nut

Length: Top 7.25 in Sides 9.5 in Bottom 8 in

Height: 2.38

Inside diameter: 1.37

Rails: 1913 spec rail

Fasteners: grade 8 bolts with phosphate finish


***Please Note***

- Screws are included with the purchase of all rail systems and replacement screws are available to purchase if necessary

- Hex wrenches/keys are not included but installation will require 9/64" and 3/32" SAE Hex Keys

*** We recommend gunsmith installation for all of our parts.  We cannot warranty items damaged by improper installation.

ONE YEAR LIMITED WARRANTY Centurion Arms warrants the initial retail purchaser that all Centurion Products will be free of defects in workmanship and material for a period of one year from the date of purchase. Centurion Arms will replace any part found to be defective. Centurion Arms is not responsible for any damaged products caused by improper installation or improper installation procedures. All Centurion Arms products should be installed by a properly trained gunsmith or armorer. Centurion Arms designs products around US Mil Spec components and there may be some components out there that do not conform. Centurion Arms will not warrant any product that has been altered or modified by the customer in any way. Centurion Arms does not recommend installation of C4 rail on barrels with pinned/welded muzzle devices and does NOT warrant labor with regards to removing pinned and welded muzzle devices That is to be worked out by the end user and the installer.


  • 5
    It is good.

    As the great warrior-poet Ice Cube once said, 'If the day does not require an AK, it is good.'

  • 5
    Carbine Cutout Rail

    These rails are excellent! Some of the best fit and finish I’ve seen in the industry. I have one in 1913 and one in MLOK and they’re awesome for FSP builds. Once you deal with those pesky taper pins you’re good to go, and the rail is easy to remove if you ever need to! Buy with confidence! Worth every penny.

  • 5
    Great Handguard

    One of the best handguards I've purchased. Fits great, mounts solid, and gives you just enough room to extend your grip out on a carbine; all while still retaining the front sight post. Much easier install than some competitors.

  • 5
    Well thought out and executed design!

    Everything from how this thing is built to the ease of placing an order and receiving it quickly is perfect. The C4 rail locks up tight. The finish and cuts are perfect and the added space along the FSB with semi turn QD mounts gives your carbine that little extra space you need. Better than any RAS/RIS was or could be! Very pleasant people to work with and I like Veteran owned family business's that care about the people placing orders for a single item. I researched a ton to get to the point of purchasing the C4 Cutout rail(to the end of the internet and beyond!!). If this rail is on your short list I recommend it over the others and I’ve handled most all of them. Great product!

  • 5
    Excellent Rail system.

    Recently installed the Centurion Arms C4 Carbine Cutout Rail to my BCM 16" carbine. This rail is awesome. Fit and finish are great, it clamps down real tight and secure, and I can't believe how light it is. I don't really notice any appreciable weight difference between it and the Magpul MOE M Lok handguard I had on before. It's longer than the KAC rail I had on my M4 when I was in the Army, and noticeably lighter. If you are running a carbine with a fixed front sight and need a good, strong yet light weight rail, look no further. You will not be disappointed. Centurion Arms will be my go to for rails and handguards from now on.

  • 5
    Worth the price..!

    As someone, much like those likely to read this review, I was bitten long ago by the AR Bug. I've been building/assembling ever since.

    I had this rail on my short list for a long time, always passing it over for other parts (other than rails) I could get for the same money.

    Soo... I honestly ended up picking one up used instead of new. But that had little impact on how impressed I was with this rail.

    Much like a Dominican girl, she was someone else's before mine, but is solid and has those sexy lines that go on for days. I enjoy getting my hands on it whenever I can.

    The machining is some of the nicest I have seen in the industry. Well thought out design and robust, I would have zero apprehensions taking this rail into an active cluster f#@k.

    MLOK is all the rage these days, but this rail shows that the 1913 spec rail has what it takes to stay in the game.

    Highly recommended. Get yours today... New, Used, doesn't matter... just get one..!

  • 5
    Typical Centurion Quality - Out-freaking-standing.

    I'm a fan of quad rails, and Centurion makes the best 2 piece quad rail. I have my C4 cutout mounted on a SOLGW FSP upper. The C4 I picked up for it wasn't brand new - I bought it used from a member on M4C and even used, it was still 100% GTG. The fit on Monty's parts are bar none. The two tabs on the front of the rail help ensure proper alignment, so do you do not have to mount an optic to get the rails to align, the rail aligns itself. The instructions are easily understood and well laid out. The first rail I bought, I didn't read the instructions thoroughly and jacked up the rail. I contacted Centurion and fessed up. Instead of doing what 98% of the other manufacturers would do (Tough titty you screwed it up, not our problem, or we'll fix it for a cost.) Monty said to send in the rail and I'll replace it. WHO DOES THAT??? Centurion Arms. Outstanding parts, Outstanding customer service. What more do you want? Pull the trigger on this rail - you will not be disappointed.

  • 3
    Heads up people

    This rail does not work with an Adams Arms piston AR. Other than that it seems like an outstanding choice. high quality very light weight.