5.56 MLOK Rail (9.5in - 15in)

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Our patented CMR rail system is a lightweight, rugged, one piece, free float hand guard that, when installed, gives the upper a continuous 12 o'clock rail. The CMR system clamps to a proprietary barrel nut that can be installed on 5.56/.223 based AR platform systems. It was designed with the top 1913 rail for mounting the most common accessories, yet does away with the need for 1913 rail at the 3, 6, and 9 o'clock positions. Here, other accessories can be directly mounted to it with a dedicated, simple, light-weight, mount. However, it does allow for 1913 rail to be added, if needed, for some less common accessories. Additionally, we built in anti-rotation QD sling swivels in 4 positions. The main objective was to have a smaller, lighter weight, more ergonomic, hand guard that maintains or enhances functionality for the end user. As professional end users ourselves, we know the importance of keeping things simple and that was our design intent here... a K.I.S.S. (keep it simple, stupid) system.


Material: 6061 T6

Finish: Type III hard coat anodized

9.5in- 8.4oz with barrel nut and hardware
10.5in-9oz with barrel nut and hardware
13in-10.3oz with barrel nut and hardware
15in-11.1oz with barrel nut and hardware

9.5in (9.45")
10.5in (10.6")
13in (13.468")
15in (15.044")

Width: 1.39(body of tube) 1.75 (at QD sling swivels)

Height: 1.910(body of tube)

Inside diameter: 1.230

Rails: 1913 spec rail on top

Integrated QD Attachment sockets - Limited Movement



- Currently our gas block is the only one that Centurion Arms can guarantee to fit under the CMR. This is due to the CMR's extreme low profile.

- Screws, proprietary barrel nut, and wrench are included with the purchase of all rail systems. Replacement screws, barrel nuts, and wrenches are available to purchase if necessary.

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


  • 5
    5.56 MLOK 15 in RAIL

    This is the second time buying on of these. This is my go to for handguards. Highly recommend them. Keeps the rifle light weight!

  • 5
    MLOK Rail

    What’s to question ? It’s a Centurion Arms rail. Looks, fit, feel and quality.

  • 5
    10.5 inch rail

    install was straight forward.
    beautiful rail.
    definitely will be ordering more from here.

  • 5
    5.56 MLOK RAIL 10.5 inch

    Rail installed painlessly
    looks killer with the 11.5 barrel
    will definitely buy more of centurion arms products

  • 5
    Hand guard

    Very nice product strong and reliable

  • 5
    13” cmr mlok

    Solid lock up. Slimmest profile I’ve handled. Feels great in the hand. I suggest the small mlok screws. If you have a heavier profile barrel the long ones can make contact with it. Quality piece for sure

  • 5
    Cm4 mlok

    Great low profile rail, it arrived in a very timely manner after order was placed. Customer service is top notch.

  • 5
    CM4 Mlok

    Easy to install, fit and finish is top notch! The CM4 is definitely in my top 5 best Rails.