SWORD International Mk18 “Mjolnir”

While most companies are now making a variation of the AR platform in .308, other companies are beginning to push that boundary further still by building AR platforms in .300 Win Mag.  Then there is S.W.O.R.D International that decided to skip the new .300 Win Mag bandwagon and go straight to the .338 Lapua for their large(er?) frame AR.  While not an entirely new concept, very few companies out there have ventured into the .338LM field.


The MK-18 is a self regulating gas piston system, sports a 26″ Lothar-Walther button rifled barrel, 10rd magazines, Keymod rail system, and CMC enhanced 3.5lb trigger system.  While some might think that an AR platform rifle shooting .338LM might weigh close to 20lbs, I actually found it to be quite manageable, and as it was built for SHOT it weights right around 15lbs and is very well made.  One feature that has been designed into the rifle has a system that allows the user to either take off or install the forward assist, based on their needs.  To top the rifle off is an in house made muzzle brake capable of helping to tame the .338LM for the AR platform.


The rifles they had with them are still in the final stages of development, but I am told that they will be starting to take orders in around two months, with shipping of the system beginning in April.  Also in the works is a family of rifles based around the same parameters as their Mk18.  In the works is the Mk17 is planned to be their .308 platform, and rounding out the group will be a rifle, yet to be designated, in 5.56 NATO.

No MSRP has been released at the time of publishing.



  • Esh325

    My biggest problem with this is that they are modifying a gun that was never designed in the first place to handle magnum level cartridges. I think there’s a reason why militaries use bolt actions when they want to launch .300 winchester magnum or .338 Lapua. Bolt actions are much more able to handle powerful catridges than semi autos are.

    • Clint Notestine

      there are many number of semi auto rifles of large caliber not including military firearms.

    • Paladin

      And yet the big daddy .50BMG is overwhelmingly used in autoloading platforms.

      There’s nothing wrong with using a magnum cartridge in an autoloading rifle, provided the rifle is capable of handling the pressures. This would not be anywhere near being released to the market if it could not.

      To me the issue is not technical but practical. .338LM is a long range precision cartridge, meaning that the rifle it is used in needs a high degree of inherent accuracy to be able to use the cartridge effectively. Semi-autos do not have the same potential for accuracy that bolt action rifles do. It seems to me that this is less about filling a need in the market than it is about showing that they can.

      • Esh325

        The .50 BMG has A LOT metal on it though and weighs a ton to achieve that durability. A bolt action .50 BMG weighs considerbaly less.

        • Paladin

          The Barrett line of rifles disagrees with you. the M107 weighs in at 25Lbs. The Gepard GM6 Lynx weighs about the same. There are bolt action .50s on the market that don’t come near being that light.

          • Core

            Serbu BFG-50 17 pounds carbine bolt action.

      • José Pulido

        Semiautos are generally less accurate than bolt actions because it’s harder to make a semi-auto with the same rigidity as a bolt action while not being completely ridiculous to carry. Lacking bolt carriers, recoil mechanisms, and receivers capable of holding them allows for more weight in the barrel, and relatively easily freefloated barrels. I think this idea(not necessarily firearm) might catch on for the sake of having very long legs, while not being as heavy as something like a .50BMG.

        • Paladin

          It’s not impossible to make a semi-auto with accuracy rivaling a bolt action, it’s just not practical. The nature of the design means that it would require excessive weight and or cost. There are more factors negatively affecting accuracy in a semi-auto platform than there are in a bolt action.

          I think the .338LM is a very interesting cartridge and has great potential for usefulness, especially because it can do a lot the .50BMG can without all the weight. I just don’t think a semi-auto system is the most practical means of employing it. The design philosophy simply doesn’t match up.

          Like I said, there’s no technical issue with a semi-auto .338, the real question is: what does it do better enough that it justifies the increase in cost and complexity? What need does this fill? If you’re doing extreme long range threat interdiction why should you choose this rifle over a bolt action that can be lighter, cheaper, simpler and more accurate?

          • José Pulido

            You’re agreeing with me at first. Yes, but those factors can be trivial in many systems, especially considering that the action shouldn’t actually be in motion until after the round leaves the barrel.

            For only extreme range shooting, there isn’t really a practical advantage overall. For long-mid range shooting, semiautomatic fire can be very useful in a system that should be considerably lighter than a .50BMG.

            Its practical use is yet to be seen, however one could guess that having a rifle that could be carried on foot patrol for long distances(a .50BMG autoloader realistically cannot) and be highly effective at extreme range would be very useful considering “extreme range” is not guaranteed.

            If simplicity and low weight was their goal, they wouldn’t have made it a piston gun, but I see your point. Complexity ties in with cost, and the Stoner pattern has been proven reliable when executed properly. A simple AR-10/15 pattern .338lm rifle would not be a far cry heavier than a bolt action, and could serve for disabling vehicles, penetration barriers, reaching farther than non-magnum calibers, and possibly as support for a sniper running a heavier caliber.

            This resembles the same type of “need” as the 13″ SCAR17. If they produce it with a 20″ barrel, it could serve as a compact, lightweight system that can go longer than it should.

          • Core

            I agree with Jose, if the projectile leaves the barrel before the bolt is in motion the potential loss of accuracy of a semi-auto is loss of muzzle velocity due to outgas into the impingement system. The .308 is currently in use with sniper units, and shoots as well as many bolt guns. I would guess the gas system will act to stabilize the pressure in the barrel and actually produce more consistent muzzle velocity pending gas port erosion rates. With new faster match triggers for the AR platforms these may be as good as a bolt gun.

    • Frank

      They’re not just upchambering the thing. For one thing the gas system is different than an AR, and second it’s designed specifically for that round. If they can design a semi auto 50BMG rifle that doesn’t fall apart, I’m sure they can do it for a 338LM too. Stoner’s system wasn’t designed for the 5.56 cartridge originally anyway, it was originally a .308 rifle designed to handle a decent volume of fire.

  • José Pulido

    Making it DI, with flat out NO forward assist(does a rifle undoubtedly meant to be shot from the prone/sandbags/bench really need one?) could get that sucker down to probably 13 or 14 lbs. What a waste.

    If I can spend tedious moments crafting my charts/handloads/working my firing solutions to take some shots, I’m sure I can spend an extra few minutes at home/at FOB cleaning my dirtier carrier and not worrying about my back being that much closer to giving out from carrying unnecessary weight. Then again, I guess I don’t really know who they’re marketing this towards, so a piston system could be a good thing for people who don’t like cleaning and don’t mind the weight.

    • FourString

      Idk, I find that being gas piston driven is pretty neat 😀

      • José Pulido

        I think piston-operated AR-15 pattern rifles are neat as well, but it just doesn’t add any utility from what I can gather. For something so heavy and for a hobby/job already involving so much work, you’d think they’d be more concerned with making it as mobile as possible rather than most forgiving of neglect.

    • sianmink

      Forward assist can be nice if you don’t want to make noise closing the action, but that’s more relevant for shorter range calibers like 300blk than 338la.

    • Frank

      You could probably get a bit more accuracy and less recoil out of it too. You’re not exactly going to be shooting cheap dirty ammo with 338 in the first place either. I could see it being helpful with suppressors though.

    • Core

      Harden up.. jk Jose, I totally agree. DI all the way, a long range platform needs frequent inspection anyway.

  • Anon

    SWORD making a hammer, last I checked hammers were making swords. Heh.

  • Lance

    Lapua Mag is not needed the Military chose .300 Win Mag so accessories and mags would be easier for the Win mag. It doesn’t offer as much ballistics over Win Mag as well.

    • José Pulido

      What accessories and magazines? I don’t believe the military has ever purchased large amounts of any 300wm semi-auto rifle. There’s only like 2 or 3 American companies making 300wm semiautos anyway(all with proprietary everything.)

      The .338LM did not exist when the military started fielding .300wm.

      .338LM can easily reach past 6,800joules(with better ability to retain that energy,) while .300wm struggles to make it past 5,500joules(and has a harder time retaining that energy.)

      I think .338lm is nice if you want to reach as far as possible without pushing fast towards being broke/not being extremely heavy(like .408CT/.416barrett/.50BMG will be doing,) and still have large amounts of energy at extreme range(which 7mmRUM and other ca.-200grain rounds might not have.)

  • ak1134

    KEEP THIS SHIT COMING!!!! I love shotshow in January!

  • An Interested Person

    Is that barrel fluted? It would appear that the barrel is not. I would imagine that with spiral fluting(which is supposedly superior to conventional fluting in both accuracy and weight savings) you could get .338LM power/range in an AR-10 weight weapon. I like that companies are starting to fully utilize the scalability and modularity of the AR platform to fill roles other than infantry rifle.

    • José Pulido

      That barrel already looks pretty thin. They could use a lighter stock, lighter grip, solid aluminum upper, and direct impingement operating system to get the weight down by a pound or more, and probably get more consistency out of the system. I doubt they could get the weight down to 9-11 lbs which is where you should see an AR-10. However, I also doubt that practicality was the goal here.

  • kalashnikev

    Also in the works is a RECCE/ SPR called “The Mk 19” and a 9mm PDW called “the M-240.” 😉