M-LOK Outselling KeyMod about 3 to 1


Fascinating. Despite being the “younger” universal mounting system out there, MagPul’s M-LOK standard is outselling KeyMod at a rate of about 3 to 1. According to my good friend Matt over at Jerking the Trigger, customers are simply putting more money into the M-LOK standard than KeyMod.

To avoid the indication of bias, Matt specifically asked companies that manufacture both rail systems in similar form to state the approximate disparity. Arson Machine reported a 3/4 to 1 ration. Midwest Industries reported about 3 to 1 and Parallax Tactical reported about 2.5 to 1.

On the manufacturing side, I personally like M-LOK more than KeyMod, which requires some special tools and a longer cycle time to physically manufacture. The spec was easy to acquire, but

On the flip side, MagPul was a pain in the arse to get them to send out the M-LOK standard. It took a call to Drake himself to get a response out of the company and get the free specification released.

The results to me are surprising, given the huge lead that KeyMod had in timing and aftermarket support. I expected M-LOK to be the leader, but the ratios far exceeded my estimates.

For those looking for a fun breakdown of the practical implications of the specifications, check out Fire Mountain Outdoors below:

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.

Nathan can be reached at Nathan.S@TheFirearmBlog.com

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


  • thedonn007

    Will keyMod eventually no longer be manufactured, or will the rail manufactures be afraid of missing out on some sales?

    • iksnilol

      Keymod is slimmer on the inside. Will have an advantage for people who want a suppressor fitting inside the handguard.

      • thedonn007

        I have ALG defense rails in both M-LOK and KeyMod, I will have to check that out. I also have some of the ALG defense EMR rails.

        • iksnilol

          I dunno, I remember reading that. Should probably have put that up as a disclaimer. 😛

      • JumpIf NotZero

        Keymod is slimmer on the inside.

        No. There is nothing in the either spec that would make this true. MLOK rails can be the same internal and external dimensions are keymod.

        • iksnilol

          Yes, but the attachment thingies for MLOK protrude, whilst they remain flush with the handguard for Keymod.

          • nova3930

            The protrusion is minimal with proper length screws. Outside a few examples, most of the rails are sized where you’re not getting a suppressor under them anyway…

    • hking

      Well there are a bazillion BCM KMR rails out there, and Noveske, and DD, and HK, and SIG, etc. The keymod market as it is now is too big to just “dump”. We are going to be stuck with competing standards for years even if one is outselling the other. I see more companies manufacturing accessories in both formats like most already do (other than magpul).

      • Jay

        Those companies invested heavily in Keymod and that’;s why they don’t switch right the way. But they will. Noveske has M-lok handguards coming out, so do DD and KAC. HK have their own version of keymod that complicates things a s well.
        In time they will all switch to M-lok.

      • Anon. E Maus

        It’s VHS and BetaMax all over again

    • SD

      BCM is stubbornly sticking with keymod as they employ the engineer that created it. A KMR rail in M-Lok would be amazing.

  • Rod Jos

    keymod rails make guns look like shelf racks.

    • Rabies


    • Hensley Beuron Garlington

      Someone else said it looks like a bunch of small penises all over their gun. Cheap shelving racks and penises do not make great looking weapons.

      • Some Guy

        You’ve clearly never bludgeoned a home invader to death with a 3 foot long double sided dildo

        • Hensley Beuron Garlington

          That’s cruel and unusual punishment.

    • SD


    • I have both, and standard shelf rack openings are slightly larger than KeyMod
      openings, in case anyone was thinking of attaching their AR to their work bench or something.

      • MichaelZWilliamson

        Damn. That would have been handy in the garage.

    • MR

      Unadorned keymod looks like there’s something missing, while empty M-LOK slots simply look like cooling vents. IMO, M-LOK contributes to a cleaner looking firearm.

  • xerodown

    M-LOK is on cheaper handguards including all the new MOE line of handguards. This would explain the numbers difference. The majority of high end manufacturers are using keymod with new ones like Daniel Defence going that route.

    • CommonSense23

      Daniel Defense is starting to go MLOK.

      • hydepark

        My Geissele is M-LOK. I would certainly say they are high end.

    • Jwedel1231

      Don’t confuse “less expensive to produce” and “lower quality”, especially when you have them coming from the same manufacturers.

      • drambus ambiguous

        I agree with this statement. Colt canada said they are switching from keymod to m-lok for their LEO and military contract rifles because M-lok has a stronger tear strength and shear strength.

        • Jay

          They are not switching from Keymod to Mlok, they never adopted the Keymod.
          They tested bot and went with the mlok.

        • Jay

          FN also adopted M-LOK for the same reasons.

    • TheSmellofNapalm

      KAC is going M-LOK. Case closed.

      • #datamine

        KAC offers both.

        • TheSmellofNapalm

          Nice work. They do now.

    • raz-0

      It’s not the MOE numbers skewing things as they weren’t one of the manufacturers polled the way the article reads.

      • xerodown

        No, but it has a ton to do with accessories purchased which was the basis of the questioning by Matt over at JTT

    • JasonM

      DD decided to go m-lok on their newest guns released at shot last week.

  • Evan

    Eh. Picatinny rails are infinitely superior to M-lok or Keymod. These fads will die out in a year or two.

    • CommonSense23

      I would love to hear how they are infinitely superior.

      • ostiariusalpha

        That would take an infinite amount of time.

      • Beju

        Road hugging weight.

      • Evan

        Been over this before. Universal compatibility, actually functional, ergonomically better (skinny foreends might be good if you’re a 7 year old girl, they suck if you’re not).

        The Keymod/M-lok fads are basically based in the absurd idea that rails are a “cheese grater”, which is completely false. They save a few ounces of weight, but not nearly enough to offset all their drawbacks, namely functionality and ergonomics.

        • ostiariusalpha

          “skinny foreends might be good if you’re a 7 year old girl, they suck if you’re not”

          Wow, you must have an amazing looking custom grip on any pistols you own, Evan. Because even a fat M9 grip isn’t any larger in diameter than a KeyMod or M-Lok rail.

          • Evan

            A pistol grip and the foreend of a rifle are not the same thing. This should be blatantly obvious.

          • ostiariusalpha

            Not the same thing, but you still have to use the same hands to grasp both. Unless your hands magically change size & shape to accommodate the difference, the same ergonomics still apply.

        • Machinegunnertim

          It’s no absurd idea. 1913 rails are tiny protrusions and not ergonomic at all. They aren’t as terrible as some complain, but far from ideal.

          Why not put the protrusion on the accessory to be mounted and the open mounting space on the gun instead. That makes for a lighter and sleeker gun. The drawbacks are few and the functionality and ergonomics are certainly superior. There are plenty of cheap accessories if you feel the need to bulk up your handguard.

          Technology evolves, 1913 rails are slowly going away. Soon you may only find them on top of the receiver of some guns for previous generations of optics.

      • iksnilol

        Well, I played this shooter RPG thing (Boiling Point: Road to Hell).

        In that game your character became faster the more you ran, and stronger the more you carried. So I developed a habit of taking spare tires of cars I “borrowed”. In the end, as I became stronger I’d be wandering through the jungle with 3-4 spare tires with me. Hilariously enough never had a problem with getting away since I could just change tires on shot up cars.

        So maybe it fullfills the same niche? That is making its user stronger over time? That is if real life is like videogames.

    • kyphe

      if you want to grate cheese with your gun picatinny is the best option by far.

      • LCON

        not a very good cheese grater though… tends to leave cheese and oil on the rail….

      • Hensley Beuron Garlington

        Leave Evan alone, he makes mention of this everywhere he can. He likes his picatinny rails the way a lot of people still think WIndows 95 didn’t need to be improved upon. I don’t know why people prefer the weight or don’t understand direct attachment, but it is what is. This isn’t a fad, unless something even better comes along, like integrally powered M-LOK, or something where attachments just hover on your weapon in place where you want them like the Light Rifle Halo.

    • Jwedel1231

      Replace “Picatinny rails” with “wood and steel” and “M-Lok or Keymod” with “polymer, tupperware guns” and this comment would be straight out of 1993. Both statements are equally valid.

    • Justin Roney

      Except for the fact that having a quad rail handguard on your rifle adds a hell of a lot of weight out front that simply isn’t needed most of the time. That’s the entire reason for the development of both of these standards, to save weight. It’s also why they aren’t going away anytime soon.

      • Evan

        They save a negligible amount of weight with the tradeoff of inferior function and ergonomics. Of course you’re almost never going to use every rail section, but it’s still better to have a universal system like picatinny rail than a silly proprietary system like M-lok or Keymod.

        • Justin Roney

          I wouldn’t say negligible. For comparison, an MI 12.6″ M-Lok handguard is 8.8 oz with the barrel nut, while a Knights Armament 12 inch quad rail is listed as 17 oz, or basically twice the weight. It doesn’t make much of a difference on the range bench, but as Chris Costa observed once, people show up to his class with all this stuff on the end of their gun, and by the end of the day it’s all mysteriously been stripped off. Even Knights Armament transitioned to their URX handguards with the middle rail sections being stripped out (but mountable if necessary) to save weight. The thin MI M-LOC handguard I put on my 300 Blackout build is much more ergonomic and controllable than trying to grip a quad rail with covers for someone like me with short, thick fingers.

          • Evan

            I would say 8-10oz is negligible, or almost so, especially spread out over 12 inches. You’re acting like a quad rail is essentially hanging lead weights on the end of the rifle. It’s not. In fact, when I take the crummy plastic handguards off a rifle and put a quad rail on, I don’t notice the weight difference. In all other aspects besides weight, picatinny rails are better.

          • ostiariusalpha

            *In all other aspects besides weight, cost, modularity, and ergonomics, picatinny is better.* fify

          • Evan

            Never compared the costs, but picatinny rail is far better for modularity – it’s literally a universal system – and ergonomics.

          • ostiariusalpha

            I can attach any picatinny accessory to a KeyMod or M-Lok rail, or even KeyMod to an M-Lok rail and vise versa, but you can’t put either systems accessories on a 1913 rail. You do understand what modularity actually means, right? Because it seems like you don’t.

          • Evan

            Indeed I do. The fact that you need to attach rail sections to the other crummy systems pretty much proves my point. Picatinny rail is universal. You don’t need adapters to attach accessories to it. You can attach anything from grenade launchers to bipods to lights, lasers, backup sights at any angle, and foregrips to picatinny rails. Not so much with the other junk. Empty rail space isn’t a problem for me at least, I’d rather have more than I need than not enough.

          • ostiariusalpha

            It’s not universal if you can’t attach everything to it. KeyMod and M-Lok are universal, Picatinny is not.

          • Evan

            Um, no. Keymod and M-lok are proprietary. To attach most of the stuff I mentioned to either requires adapters – in the form of picatinny rails. That’s more junk you need to buy just to get it to the basic level that picatinny rails offer you out of the box.

          • Ben

            Super troll??? Or are you serious that you don’t understand proprietary? And I’m glad you think a quad rail is super ergonomic “Andre the giant”. Also I use a 42″ barrel shotgun because weight at the front of the gun means nothing and I work out so I can’t tell the extra 10 ounces of barrel up there…

          • Justin Roney

            Better…how? Weight = fatigue = worse performance by the shooter. Better repeatability when re-mounting optics? Most of the M-LOC (and keymod) handguards have full rails on top to reduce mounting error, but most changes of zero with optics with quick detach mounts are dependent on the quality and workmanship of the mount. You don’t need to be within 1/2 MOA when you re-attach your flashlight or bipod.

        • C77A1

          But neither M-Lok nor Keymod are proprietary; the specs for both systems are completely open for free use.

        • iksnilol

          Half a pound to almost a pound isn’t a negligible difference.

          Picatinny is just as universal as Mlok or Keymod is.

    • raz-0

      If I manufactured pricey acessories, then I’d have to agree with you.

      If I wanted to build a lighter rifle with the ability to accept accessories and avoid abrading everything in sight, I’d have to prefer keymod or mlock.

      Given the fact that the price of rail sections for both have reached such low prices, you really don’t give up much utility with that weight savings and ergonomics bump.

    • n0truscotsman

      I assume you mean ‘quad rails’ when you are referring to ‘picatinny rails’ in this context?

      If this is the case, I disagree strongly. The ergonomics (comfort, especially for differing grips), cooling, cleaning, and weight/material savings are irrefutable advantages to M-lok systems.

      You dont even use 90 percent of the railing you are given, not unless you attach more than a weapon light and IR-laser (which, meh, why the eff would you? and what?)

      Quad rails will fade into obscurity, alongside carrying handle picatinny adapters.

  • Ambassador Vader

    Excellent solutions to something that wasn’t broken. Buy a rail. Buy adapters for that rail to go to picatinny. Buy rail covers for those rail sections so you don’t have to take them off. Hope to God that the rail doesn’t go extinct in 5 years with the industry wanting you to buy more, newer designs to fix the problems with m-lok and keymod that weren’t actually there. Wash. Rinse. Repeat.

    • JumpIf NotZero

      I’m either missing all the sarcasm in your post… Or you get the all of bullet points but still have come to the wrong conclusion.

      Proprietary adapters were the absolute dumbest thing they could do, it was backwards from 1913.

      • Ambassador Vader

        It’s sarcasm. I prefer picatinny.

        • Jay

          Nobody cares……. just like nobody cares my uncle prefers vinyls, or my neighbor still prefers his 100 lbs CTR monitor.

          • Ambassador Vader

            you’re complaining an awful lot for someone who doesn’t care.

          • Ambassador Vader

            please fill out in triplicate.

          • C77A1

            This seems silly. The fellow stated his opinion, no reason to turn this into a flame war. I for one prefer M-Lok over 1913 simply for the reduction in male attachment features; you have a smaller OD, fewer harsh edges, weight savings, and cost savings with this method.

      • hydepark

        1913 wasn’t the first. M-LOK certainly won’t be the last. I have fun trying out different things and having a stash of parts to change things up or help a friend out with a build. My M-LOK rail was my first rail purchase and I started out with pic sections and now I’m moving more towards the direct attach. It’s like Lego for adults!

      • nova3930

        They’re no more of less proprietary than 1913, it’s just that BCM/VLTOR/Magpul control the specification instead of .gov. The dimensions and specs for all 3 are openly available for anyone to use….

    • Most people direct attach. Rail sections are only for parts that don’t have the option to switch out to the KM or M-Lok adapter.

    • nova3930

      I don’t use rail adapters with any of my m-lok stuff. I attach directly to the rail. Big gain in slimming down the profile using Arisaka Defense m-lok scout light mounts…

    • Jay

      You don’t need picatinny adapters anymore. The only reason to use it is if you want to attach picatinny based accessories you already have.
      Right now, you can buy pretty much any accessories you want, with M-lok interface, that attach solid, clean and flush, directly to the M-lok handguard.
      M-LOK = Clean, slim, light, strong and efficient.

    • DonDrapersAcidTrip

      If you’re wanting to buy one thing and be done with it forever and don’t want anyone to try to improve on it because it’s “good enough” for you, you’re in the wrong industry.

      And stop dismissing every single thing to come out as “a solution for a problem that doesn’t exist” because you personally can’t concieve of a need for it. Every one who uses this tired cliche is doing nothing but demonstrating how backwards and unimaginative they are.

      • MichaelZWilliamson

        A) That’s pretty much every industry.

        2: welcome to the internet.

  • Geoffry K

    Too expensive. I have a 15″ free float quad picatinny rail handguard made in China for $35 and bought from eBay. Works fine.

    • SD


    • andrew

      I’m pretty sure, when the Chinese knockoff M-lok hanguard shows up on Amazon, it will be half the price.


      • Cymond

        I haven’t seen Chinese M-LOK handguards yet, but I have a $45 KeyMod from Amazon on my AR pistol build. I didn’t know if it like a pistol, so didn’t want to spend much on this build.

  • zerowolf04 .

    I was not impressed with Mlok in regards to polymer to metal mounting(Remington 700 stock) it was supposed to be why it was created and didn’t really see the advantage over say the old moe mounts. It will be pretty hard to beat a company like Magpul in accessories market but as for now I see no reason to switch my keymod over.

  • Jay

    Anyone not a Keymod fanboy, could have seen this one coming from a mile away.
    The first time i saw the M-LOK, I had that “Evrica!” moment. The solution that just feels right and the handguards just look natural.

  • Smart money was always on the one designed for polymer.

  • SD

    It’s easier to manufacture M-Lok slots than keymod. Less machining processes.

  • Mick

    Oh, you actually got the M-lok spec?
    I’m still waiting.

  • blotonthelandscape

    I don’t know about that. Reports of Keymod failing (falling off) have been fairly common since it’s release and Colt Canada tested both systems and choose M-LOK.

  • #datamine


  • Mike Lashewitz

    Thanks for the video AND the “outtakes”! LOL! The plus with Picatinny is you can easily make your own mods to attach with no difficulty.

  • Ben Pottinger

    Personally I see this as a good thing. Competing standards are always a huge problem in the tech industry and seriously reduce the number of accessories available and increase the prices of them. As long as m-lock is either an open standard or has a cheap, and open licensing system I’m happy to see it “win”.

    It will suck for keymod owners though, but maybe it will create a market for adapters?

  • Alex

    Consumer side sure but military?

    SIG CSASS submission = keymod
    HK CSASS submission = keymod
    SFOD-D SR-25 = keymod

    • blotonthelandscape

      Interesting that both SIG and HK submitted guns with highly modified versions of Keymod and choose not follow the regular open source Keymod docs that are floating around on the net.

      I read somewhere that SIG system is partly compatible with regular Keymod stuff but the HK system is obviously completely different (even the slot spacings go in the opposite direction).

  • Bal256

    Making a product in keymod configuration makes as much sense as making an app for iphone only. Out of all the “smart” products from SHOT that interface with your phones and tablets, I don’t remember hearing android once. Why anyone wants a smaller target audience is beyond me.

  • Mark Spreadborough

    Nathan!! Thanks for the video share!!!
    Fire Mountain Outdoors

  • Bob Crisman Jr.

    An interesting article with a nod to Fire Mountain Outdoors