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: 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. Replacement screws are available to purchase if necessary.


  • 5
    Great Handguard

    Posted by John on Mar 19th 2021

    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!

    Posted by Michael Roth on Apr 3rd 2020

    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.

    Posted by Joe on Oct 26th 2019

    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..!

    Posted by Lou on Sep 10th 2019

    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.

    Posted by R. Salmon on Jun 27th 2019

    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

    Posted by tTerry on Feb 27th 2019

    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.