First adoption of M-Lok by the U.S. Military

Soldier Systems Daily is reporting from Modern Day Marine that the U.S. Army’s Compact Semi-Automatic Sniper System (CSASS) will be getting an upgrade from H&K in the form of Geissele rail systems, in particular it appears to be their Super Modular HK Rail that retails for $430. The rails are confirmed, but unconfirmed posts state that the barrel twist will become tighter with a 1/8 twist, and a change from the H&K 2 Stage trigger to a Geissele trigger.

But most importantly, this appears to be the first time a legitimate and public U.S. Military contract has an M-Lok system incorporated into it. Keymod has been available with the PSR contract rifles in addition to numerous other small arms in use by Special Operations forces. But M-Lok hasn’t yet made it in the world of standardized government contracts, almost a holy grail of accomplishment within the firearms manufacturers community. Early on TFB we reported that M-Lok was outselling Keymod with a three to one ratio, in addition to Colt Canada even coming out with M-Lok options on their handguards as well. Could this adoption be the beginning of a trend that turns the tide against Keymod? Granted, it is a relatively small contract insofar as truly successful military contracts go. But seeing how the industry sometimes takes a very leading cue from the military services that sometimes drive it, this could be an early indicator.


Infantry Marine, based in the Midwest. Specifically interested in small arms history, development, and usage within the MENA region and Central Asia. To that end, I run Silah Report, a website dedicated to analyzing small arms history and news out of MENA and Central Asia.

Please feel free to get in touch with me about something I can add to a post, an error I’ve made, or if you just want to talk guns. I can be reached at


    • Vitor Roma

      Dude, one or two posts ok, but spamming your shirt everywhere will only get people pissed.

      • AC97

        Seconded, self-promotion gets old really fast.

      • iksnilol

        Can we get him banned?

    • Black Dots


      • BillC


        • BravoSeven

          And no one needs this shirt

    • 11b

      Go away. Your shirt is tacky and your ‘marketing’ is annoying.

    • Apparently you didn’t get the hint that you can’t come on TFB and et free advertising by posting comments. One more time and I’ll be forced to ban you from TFB.

  • Black Dots

    I honestly wonder of Keymod would still be around if BCM weren’t backing it.

    • Harry’s Holsters

      They’d be smart to adopt M lok and let keymod die out. On Primary and Secondary’s Youtube Roland basically said the problem of the Keymod is it’s a flawed design that in it’s current form will tear apart from use of VFG or doing barricade work and if it were flipped the recoil impulse will kill it. No win and then the whole thing about add ons being harder to make out of polymer and thus more expensive. My next AR will have M lok.

      • Black Dots

        Unfortunately, I think BCM hired the dude who invented Keymod. I imagine that would be an awkward work conversation: “Eric, great job on Keymod, but no one cares about it anymore and we’re switching to M-LOK. Anyway, enjoy the rest of your lunch.”

        • Harry’s Holsters

          Business is business I think Eric Kinsel would understand. Keymod broke the initial ground as far as mass market adphtion and M lok was able to take the idea and fix the issue of the system. Timing.

      • Farook Karrmaluk

        Do you have a link to that video?

    • All the Raindrops

      It’s ridiculous that bcm doesn’t sell mlok models of the rails they stock. Not referring to the kmr; they’ll only sell keymod products period.

      • Black Dots

        They’ll probably be the last to let it go. BCM hired the guy who invented Keymod, so they are wedded to it for the foreseeable future.

        • All the Raindrops

          That certainly appears to be the case.

          Bad 4 business

          • Black Dots

            Yeah, I would love it if BCM offered some MLOK options. I love Magpul and BCM, but I feel like they are two of my friends who just won’t get along for some reason.

  • ostiariusalpha

    Dammit, now how am I supposed to rub Alex’ face in it? So frustrating!

  • Uniform223

    I still believe the CSASS should’ve went to the M110K.

    • GD Ajax

      Than you need to get over it, KAC lost big time. If they bothered to make a quality rifle, than CSASS program would have not be necessary.

      • Uniform223

        M110K is used by U.S. Special Forces… they seem to like it. The M110K would have been the cheapest and quickest solution as it only involves (in my understanding) changing the M110 upper for the M110k upper. As far as I know the H&K CSASS entry has ZERO compatibility with current M110 SASS.

        • GD Ajax

          SOF meaning that have an unlimited budget to waste money with. It by no means that the M110K is a good weapon. Compatibility with the SASS is meaningless. The Army sniper school decision is just as valid as any SOF unit.

          • Uniform223

            “Compatibility with the SASS is meaningless.”

            Changing the Upper receiver on the M110 with the M110K Upper is meaningless? It would have been the quickest and perhaps most cost effective solution rather than adopting a completely new weapon system (H&K’s CSASS entry which is based on the G28 from my understanding) that has little if any compatibility with current M110s in service. Hell the G28 has a proprietary magazine… how is that cost effective?

            The fact that the M110K was already in US Military service (granted with Special Forces/SOF/SOUs … what ever people want to call them nowadays) meant that it was already in the supply chain. The US Army could have done a “soft launch” of the M110K replacing M110 uppers with the M110K upper already in use. How and why the US Army went with something so much more expensive and different then what they already have is beyond me. The Good Idea Fairy was hard at work that day.

        • that other joe

          “as it only involves (in my understanding) changing the M110 upper for the M110k upper”

          And, like any AR-15 conversion from rifle to carbine, changing out the buffer tube, stock, buffer, and buffer spring, and potentially the back plate and a few springs. A totally simple, drop-in component….

          • Uniform223

            Still a whole lot more simple than completely different as well as new platform. Again… M110K was/is already in use by U.S. Military… albeit in SF units. Changing out the upper and the stock is STILL a cheaper, faster, and effective option than what the US Army did in my opinion. The US Army already screwed the pooch in a lot of high profile programs. This was an easy problem was an equally easy solution. Why they had a competition and picked a system that will most likely be more expensive while still offering the SAME capability is beyond me.

          • George Dean

            How about just an adjustable gas block & nothing on the lower.

      • n0truscotsman

        The problem wasn’t lack of a *quality rifle* per se, but the requirements, which demanded a shorter rifle than the M110.

        • Bullphrog855

          I honestly don’t get why the Army even needed a shorter M110.

        • Uniform223

          KAC was already providing a shorter version of the M110 with their M110K

          granted most pictures I’ve seen on the interwebs of the M110Ks being used are in the USMC but it shows that there was already an available and cheaper solution.

          • n0truscotsman

            I actually remember you posting about that rifle before. Thats the one.

            You would think the choice would have been obvious, but apparently not. I *really* want to know the justifications for H&K too, because IMO its a mistake.

          • CommonSense23

            Why did the marine corps go out of their way to adopt a new 1911 in the last 10 years or decide to adopt a 416 that offers them the same capabilities as a M4A1 at three times the cost. The military does stupid crap all the time.

    • BillC

      I’ll pass your comment to the Army. There may still be time.

    • Anonymoose

      Should have been the SCAR.

      • CommonSense23

        No, no it shouldn’t..

  • Vhyrus

    As someone who bought a crap ton of keymod recently, I object to this development.

  • Anonymoose

    1/8? That doesn’t make sense. 1/8 is what you use in a .300 Blackout to stabilize 220-240gr subs. 1/10 is the NATO standard and will do everything up to 200gr and maybe beyond at .308 Winchester velocities. The use of lightweight hunting boolits in the civilian realm is what is selling 1/12 barrels. I’m not sure what the standard HK417 twist is, but HK lists the MR762 LRP’s twist rate as 1/11 (which should be suitable for 175gr ammo used by the US).

    • CommonSense23

      Faster twist rates are pretty much the future. Todd Hodnett has been preaching it for years and he is the SME Socom calls for all their long range questions. And the 300BLK program showed the same results. The faster the twist rate the better the performance at distance.

      • iksnilol

        We need a 1/4 twist

    • the dude

      The faster twist gives a bit of over stabilization which helps extend the range of the cartridge when the bullet is passing through the trans-sonic zone where most bullets tend to destabilize and start to tumble.

    • Black Dots

      It seems that 1/8 is becoming more and more common. I have a feeling this is the influence of 223 Wylde on the marketplace…or not. Hell, I don’t know. What am I, a writer for the Shooting Times? It’s late and I feel like shitposting.

      • CommonSense23

        What does 223 wylde have to do with a 1 in 8 twist for 7.62?

        • Black Dots

          It has to do with my inability to read the main article correctly, apparently.

      • Zachary marrs

        .223 wylde is just a different type of chamber, it has nothing to do with twist rates

      • Anonymoose

        Yeah, but this is a 7.62x51mm NATO/.308 Winchester with a 1/8 twist. .30cal rifles usually have 1/10 or 1/12 twists.

  • A bearded being from beyond ti

    MLOK sure is nice.

    btw how are you supposed to pronounce “Geissele”?

    • All the Raindrops


    • ostiariusalpha

      It’s pronounced gaɪs’li, rhymes with nicely.

      • A bearded being from beyond ti


    • Black Dots

      With a thick Philly accent.

    • The Brigadier

      Hard G rhymes with deisel.

  • I wanna say I called this one a while back, but it was in the comments section and I’m too lazy to look for it.

    • JumpIf NotZero

      Really no surprise. There was less than a 0% chance the mil was going to work around HK’s (utterly stupid) unique backwards keymod.

  • Henry Reed

    So does anyone have any information on why HK won this rifle contract over KAC?

    • Uniform223

      From my understanding and what I’ve read the U.S. Army didn’t want a sole source provider.

  • micmac80

    Key mod is structuraly flawed and unnecesarily complex and wonder why its as popular as it is. M lok is far superior

    • Uniform223

      Do you have any scientific data to back that?

    • Black Dots

      Keymod was first to market with a viable negative space attachment system, so they got a lot of traction from that. Add support from a well-regarded company like BCM and here we are.

      • Magpul

        First viable negative space attachment system for the M16/M4 was MOE slot system first introduced by Magpul with the original MOE handguards in 2007. The MOE slot system was second only to the Pict rail in terms of adoption up until it was replaced by the MLOK system on all Magpul products in 2014.

        • Black Dots

          Yeah, but MOE was for people to use Magpul stuff on Magpul stuff. Keymod allowed people to use Keymod compatible whatever made by whomever on Keymod rails made by whomever. That made it a direct alternative to 1913 rail. Only when you dudes made MLOK openly available via free license did MLOK go head to head with Keymod and 1913.

  • marine6680

    So… I keep seeing people talk about keymod being inferior and an unsound design…

    I have never actually seen any data to confirm that. Granted I didn’t look hard.

    Personally, I prefer mlok based on aesthetic alone, and also like the more simple nature of it… But I don’t care so hard that I hate my keymod stuff.

    Granted, it’s only on my BCM rifles, and my fiance’s rifle I built using a BCM rail. Had I the option from BCM, I would have went mlok.

    • iksnilol

      You don’t like the look of sexually explicit industrial shelving?


  • LilWolfy

    Biggest gem from that article is the twist rate. It takes a tighter twist to keep projectiles gyroscopically stable through the transonic region of flight.

  • Wingbert

    BCM needs to just drop Kinsel from their staff and start making/selling mlok accessories. It’s just a matter of time before that standard goes the way of HDDVD