Keymod vs M-Lok: Which Will Set the Standard?

Keymod vs M-Lok: Which Will Set the Standard?

Feeling like Magpul’s M-Lok muddied the waters of the universal attachment market? Or perhaps you are cheering Magpul for challenging KeyMod? Regardless of where you stand, it will only benefit the consumer to have more options. But is their room for both?

In case you don’t know what I am talking about, here is some history: In 2012 Vltor Weapon Systems introduced an “open source” universal attachment system for accessories. The idea being to directly mount accessories to the hand-guard and the design is free for anyone to use.

Enter Magpul: At the 2014 NRA annual meeting, Magpul introduced a new “open source” accessory attachment system. Known as M-Lok, it is Magpuls attempt at industry wide standardization. Both systems have the same goal, but offer different solutions to the modular rail equation. KeyMod uses an attachment system with “keyholes” that allow accessories to slot in and then are tightened down with captured screws.

The KeyMod system on a VLTOR VIS KM

The KeyMod system utilizes a “keyhole” to index accessories and attach them directly to the rail.

Where as M-Lok uses a method to index accessories against rectangular cut-outs in the rail.

Magpuls M-Lok utilizes rectangular slots to mount hardware.

Magpuls M-Lok utilizes rectangular slots to mount hardware and accessories.

Consumer Battle

Both designs are attempts to consolidate the rail market to a new “modern” standard, and to cut the complexity of manufacturing rail systems with the picatinny rail. Which one will last and which will become a legacy system?

I don’t believe that this battle will be one where the technically better system prevails. This is going to be a pure cost and popularity battle. Magpul claims the M-Lok standard is cheaper and easier to manufacture. M-Lok is also capable of being used in plastic hand-guards; this will result in a massive production of products from high-end to dirt cheap Chinese import junk. M-Lok adoption will be quick and widespread especially with Magpul’s commitment to produce accessories for their rail.

This was an important aspect that Vltor missed when they introduced KeyMod; there were too little in the way of accessories to wow consumers.

Only recently have we seen any steam in KeyMod’s engine. Finally, new accessory designs are making their way to pre-production. Companies took a “wait and see” approach to KeyMod before committing to the standard, but now their attention and product development will be split between KeyMod and M-Lok. With Magpul leading the charge of M-Lok accessories, consumers and manufacturers will be swayed towards the M-Lok standard at a faster pace then KeyMod. Further cementing the deal is backwards compatibility with old MOE accessories. Any accessories purchased prior to M-Lok will function with an adapter plate. Touche Magpul.

So is KeyMod doomed?

No, we can expect continued KeyMod support for many years.   Multiple manufacturers have began to run with the KeyMod system and have invested substantial time and energy into supporting KM. We have a few big names that have released KeyMod systems: Noveske, Bravo Co, Vltor, and Knights Armament to name a few. These companies set the standard for building rifles which “set the standard” for a hard use weapon. I doubt these companies will slow support for KeyMod at the moment… and that is just what’s going to keep KeyMod alive. Eventually, I think the development of new KeyMod accessories will slow to a trickle…

Unless KeyMod moves into military procurement. That would be just the game changer KeyMod needs to sway civilian consumers back to KM. With a big military contract, new accessories will start to flow into the mix rapidly.

Technically, Which One is Superior?

First off, I doubt any consumer will push hard enough to test the limits of either the KM or M-Lok systems. Until we see them in use on a widespread basis, it will be hard to discuss durability or product failure. Consumers are unlikely to push either design to their failure point. Until we see widespread breakage of certain components on a regular basis, I will call a draw on durability.        

Wrapping Up

I could be 100 percent wrong with my theory… But I see a strong possibility that Magpul has stacked the deck in their favor. They make affordable products and are a trend setting company in this industry. I think they will gain momentum quickly over KeyMod.

Disclaimer: I am not sponsored by Magpul in any way, shape, or form and the only product I currently own from Magpul are Pmags. I do have a KeyMod product on order.

Written by lothaen


  1. mcthag · May 10, 2014

    Vltor’s drawing, which you include in your post, tells the story about which will be more widely adopted. Basic dimensions and geometric tolerances are expensive to hold. M-Lok is a rectangle with tolerances (the exact ± has not been published); thus a lot cheaper for the handguard maker.

    • mcno · November 19, 2014

      Proper use of GD&T almost always results in more generously-sized tolerance zones as it more fully conveys design intent. This leads to lower cost. Cost increases from GD&T’d drawings result from uneducated machine shops trying to bullseye every feature when they don’t take it upon themselves to learn the standard.

      That is a fairly good drawing and the tolerances are very reasonable.

      • J · November 25, 2014

        At least one person gets GD&T. There’s no difference in expense due to the application of control frames. Both standards require similar amounts of machine time to produce, but actual time will depend much more on the shape/profile of the extrusion used than on which standard is chosen.

      • Kurt Phillips · September 21, 2016

        What the hell is ‘GD&T’?!

        • Kyle Reese · February 11, 2017

          Geometric dimensioning and tolerancing (GD&T) is a system for defining and communicating engineering tolerances. It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that explicitly describes nominal geometry and its allowable variation. Google is your friend.

  2. shark92651 · June 11, 2014

    Another point not mentioned, and maybe it is completely subjective, but I would argue that M-Lok handguards also look nicer than KeyMod handguards. KeyMod looks too much like an industrial warehouse shelf. Basic slots have been common on handguards for a long time. Let’s face it, appearance and how “cool” your rifle looks drives a LOT of sales in this industry.

    • lothaen · June 12, 2014

      Aesthetics factor into it, for sure. I don’t mind the looks of Key-Mod, but I agree… looks sway purchases.

    • garypaul64 · July 21, 2015

      I have over 25 years in sells, (Golf Industry), and to be honest I think you just nailed it. Over the years I watched people purchase golf clubs on looks alone never mind if they improved their game. I see the same thing happening here, come to think of it in my back stock room I had a lot of items stacked on metal shelves that resembled the KeyMod look.

    • John Mead · February 22, 2018

      If you’re in to how “cool” your firearm looks, then perhaps you need to stay at home and play with your dollies.

  3. John Topher · June 16, 2014

    M-LOK rails are popping up fast. ALG, Aero and Midwest are already selling rails. The ALG M-LOK is cheap. All of the are light as well.

  4. Joel Bowman General Manager CIM Tactical · October 23, 2014

    First let me start by saying we at CIM Tactical make both KeyMod & M-LOK handguards and as a manufacturer there is definitely a difference between manufacturing the KeyMod vs. M-LOK, but in the grand scheme of things the M-LOK saves only a small amount of run time in the mill but still uses the same special tool we use to make certain cuts on the KeyMod so cost to produce either profile is very close.
    As an active shooter I have used both systems but I am leaning to the M-LOK because it is so easy to move sections around and the positive lock system is unbelievably strong. I attached a 5 slot section and accidentally forgot to lock the second bolt and after shooting a match found that the M-LOK section didn’t move at all telling me that the second bolt is more like a redundant system than required.
    I have had a KeyMod section come loose during a match due to me not getting the bolt completely tight and the polymer part being a bit worn.
    The one thing both systems have going for them is super light weight, a 15.0″ KeyMod rail or 15.0″ M-LOK rail only weigh 9.8 oz. compared to 17.8 oz. for a slim quad rail or a monster 22.5 oz. for a full quad rail.
    In summary I think the M-LOK will ultimately surpass the KeyMod for a few reasons with one being the better locking system and two and most important of all, the strength of Magpul’s brand and marketing power.

  5. Julian · February 1, 2015

    Tough decision for me too. I’m about to get a BCM 14.5 mid length upper. Been planning on Keymod. Even if I end up with KeyMod, I may get an M-Lok rail to install and try out.

  6. Tactical Joke · February 12, 2016

    I have both. My future purchases will most likely be M-Lok.

  7. JohnP · February 12, 2017

    M-LOK > KeyMod

  8. ponch · July 25, 2017

    How about no LOK and use ALEXANDER ARMS MK10. Best part is you won’t need that NASA thermal glove anymore.

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