MagPul Releases M-LOK Attachment System

Announced via Soldier Systems earlier today, MagPul has debuted its new open-source M-LOK rail attachment system, the next generation of the MOE slot system. Unlike other systems and true to MagPul’s heritage, the M-LOK system is designed to be used with either metal or polymer systems.


Aimed squarely at KeyMod, I would estimate that it will be quickly picked up by the OEM community. Since it uses straight cuts, it will cost significantly less machine time to produce compatible rail systems. Secondly, with less material required, I can see systems being lighter. Geissele Automatics is already on board with their upcoming MK8 rails. 

In MagPul’s own words from the M-LOK FAQ:

Q: Why the M-LOK system and not another existing open source system such as KeyMod?
A: In our experience, KeyMod is not a suitable mounting system for polymer products,
because a conical nut is used to secure the accessory in place. On plastic materials, the
conical mating surfaces of KeyMod will either promote cracking or loosening due to creep
and deformation of the material.
In addition, KeyMod’s undercut also requires the use of specialized cutters for CNC
operations or complex injection mold designs. As a result of the KeyMod design, the QC
process becomes significant with high volume manufacturing, resulting in increased time
and cost when compared to manufacturing the M-LOK system

The full details of the system can be found in their FAQ available here.


You can bet I will go hands-on at NRA later this week!

Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • steveday72

    M-Lok is almost identical to the system that Daniel Defense uses on the MFR (Modular Free-float Rail) which I have.

    • sianmink

      I knew it looked familiar.

  • Garrett

    Interesting fact (If you receive the Magpul e-newsletter like I do and I am sure the author does): Magpul has NOT released it for public domain. They are requesting that any interested manufacturers sign a free license agreement.

    “By licensing the system for free, the same no-cost access to the system is provided

    as with an open-source release. However, this method protects both manufacturers and

    consumers by assuring that all products bearing the M-LOK logo are made to proper

    specifications and will work with all other M-LOK products, preventing problems with

    compatibility and inaccurate or counterfeit versions of M-LOK products.”

    • Cymond

      Interesting. Is the M-LOK design patented, or is it just a copyright on the M-LOK name & logo? If not patented, then some companies may make unlicensed products that are still compatible.

      • An Interested Person

        Patent pending according to the FAQ.

  • Nicholas Chen

    Bring me back some Nathan, pretty please haha.

  • Cymond

    The hopes of reduced machine time (and reduced cost) are interesting, as is the potential for more weight savings. However, KeyMod is already established by a few years of manufacture (at least the handguards are, there aren’t very many KeyMod accessories yet).
    So is there room in the market for 2 systems that are directly competing? Is this Betamax vs VHS (one dies), or Playstation vs Xbox (both still exist after several generations)?

    • Sam Schifo

      I bet one will eventually kill off of the other, unless they both start offering options that are exclusive, like certain types of accessories or something. That is the reason that there are still different consoles, they each have exclusive features and exclusive games that the other one doesn’t have.

    • Jim

      I got to fondle the Geissele M-LOK rail at the NRAAM. Despite having those flats as shown in the picture, it handles REALLY nicely. It’s about 1.75″ to 2″ across, so even though the flats are pretty pronounced, it’s still really easy to wrap your hands around it. The reps at the Magpul booth were saying that Geissele was able to shave off 20 minutes of machine time per fore end, too, which is nothing to sneeze at. Honestly, I thought Magpul was too late to the game with this one, but after handling it, I think they might have just done it again.

  • Marc

    First people bitch endlessly about the XM8 attachment system, 10 years later everyone makes their own flavor of negative footprint mounting interface.

    • MIKE

      XM8 was stupid. I’m still bitchin about it.

  • JT

    It’s funny because Magpul doesn’t care about how their MS3 polymer hardware deforms against metal attachment points

  • gunslinger

    open source…licensing…patents… i’m in
    (que popcorn gif)

  • PCAP redux?

    • Dale

      Basically. I’m surprised it took so long.

  • Airman596

    I hope this wins out over keymod personally. Keymod rails are both expensive and ugly looking. M-LOK could improve both cost and appearance. Win-win.

  • Fared

    You jerks are LATE!!!