C4 Rail, 12in Front Sight Pocket Rail Handguard (for Carbine Gas Systems)

Usually Ships in 2 to 3 Business Days - Custom Cerakote Lead Times Vary (See Disclaimer Below)
(7 reviews) Write a Review


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.

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


Material: 6061 T6

Finish: : type 3 hard coat anodized

Weight: 14.2oz with screws---1.1oz with standard barrel nut

Length: 12.16n (pocket located for carbine length front sight post)

Width: 2.1in

Height: Install 1.978in / end of rail 2.326in

Inside diameter: 1.37

Rails: 1913 spec rail

Fasteners: grade 8 bolts phosphate finished




***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


Custom Cerakote Disclaimer:

Custom Cerakote is completed per order.  Our Cerakote room runs one color at a time so your ship date will be subject to the color rotaion at the time the order is placed.  You will receive an email confirmation once the item has actually been packaged to ship.

Cerakote items are not guaranteed to match separate batches or Cerakote completed by outside parties.  While we strive to keep our mix uniformed for our own products, we can't say for certain what Walter and Jesse cooked up in their lab out in Albuquerque.

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
    C4 Rail, 12IN Front Sight Pocket Rail

    Excellent quality. Cerakote look great. Quick turnaround time and shipping. Outstanding customer service from Corrie who helped me choose the right rail for my build.

  • 5
    C4 FSP Cutout Rail

    Stellar product, as always.

  • 5
    C4 rail

    The rail was easy to install and is rock solid. I've had a chance to use this rail for a few months now and I absolutely love it.

  • 5
    C4 front sight pocket rail (carbine length gas system)

    Top shelf quality rail. Precisely machined with excellent anodizing, lightweight and handy yet robust. Centurion Arms products have no peer.

  • 5
    C4 FSP rail

    Great rail , a little expensive but Centurion Arms makes great items. If you want solid equipment , from a solid company this is it. Veteran owned and operated means a lot. Will continue to buy from them.

  • 5
    Great Quad Rail Option

    If your tool collection is a Dremel, some hex wrenches, and some oil you have everything you need for installing this rail.

    I use this so I can access an adjustable gas block and have an extended sight radius. It's lightweight enough that you can carry it at a class all day long and sturdy enough that when it gets smashed into a door frame at that class it won't bend.

  • 5
    Rock Solid Rail

    Most Rock Solid Font Sight Post Cutout Rail that I have used and it uses a standard barrel nut. No need for proprietary tools. Outstanding!