GD O&TS – Lightweight Medium Machine Gun in .338 Norma Magnum

Back in 2012, General Dynamics Ordnance and Tactical Systems unveiled their belt-fed Lightweight Medium Machine Gun, in .338 Norma Magnum. I saw the weapon, but didn’t take it too seriously, because at the time, there was no money in DoD for new starts. I remember being asked by a friend what a .338 machine gun could be used for and I replied, “shooting $10 bills.” It just seemed like the timing wasn’t right. Now however, its prospects are looking better than ever.

A few things have happened since 2012. First off, the development of Polymer cased ammo has progressed to the point that it is now viable. Second, there’s now money available for an initiative like this. What’s more, we’ve got a Chief of Staff of the Army who wants to retool the Army for the next war. The LWMMG offers an overmatch capability that promises to change how the Infantry fights.


Developed via internal R&D Dollars, GD identified a capability gap between the M240 and M2 machine guns. They set about to create a machine gun which would offer similar handling characteristics as the M240, yet rival the reach of the venerable M2. Combining the .338 Norma Magnum cartridge and their “Short Recoil Impulse Averaging” recoil mitigation system, the LWMMG can engage targets out to 1700m (some GD literature offers 1900m) with a 300gr Sierra HPBT, FMJ, or AP projectile. That round offers 5 times the energy of a 7.62 projectile at 1000m.


While GD chose the .338NM over the .338 Lapua Magnum due to its less tapered case for use in belts, and the promise of longer barrel life, the LWMMG can be converted to use the .338LM cartridge.


At the 1700m range, the performance of the M2’s .50 round limits it to use as an area weapon, while the .338NM has been demonstrated to hit point targets at that range. This more than adequately overmatches the Russian PKM which has been a concern for anyone who has found themselves at its receiving end.

The weapon weighs 22 lbs which places it well within the 240 weight class of 27 lbs and rivals the new M240L. The LWMMG also features a quick change barrel with fixed headspace and timing as well as integrated MIL-STD-1913 rails. Additionally, there is a collapsible stock and GD has been offering the weapon with a 6x optic.

This 2012 chart depicts the weights of the M240, LWMMG and M2 and is based on conventional, brass cased rounds for the LWMMG. In addition to weapon upgrades, Poly case technology is going to further lighten that load, or better yet, increase the amount of ammunition a machine gunner can carry.


Finally, GD has also successfully demonstrated the LWMMG with a suppressor.


Conceptually, the Army is interested in something along these lines, but out in the nebulous world of the future.  The thing is, the stars are aligning now.

Now is the time for one of the services or USSOCOM to write a requirement for this capability. Let’s see what industry can do to offer the US Warfighter a capability unparalleled anywhere else. Take that, PKM!

All photos from General Dynamics.


29 Responses to “GD O&TS – Lightweight Medium Machine Gun in .338 Norma Magnum”

  1. Steve says:

    If this would be used primarily a stationary or vehicle-mounted role, I can see it being a good thing. However, the scale points to this being unfeasible in a dismounted role. Certainly, the gun itself is lighter than the M240B, but the gun is useless without ammo, and 600 rds of .338 linked would weigh (based on the wt comparison table above) 72 lbs., vs. 600 rds of linked 7.62 weighing 39.75 lbs.

    • P.J. says:

      “This 2012 chart depicts the weights of the M240, LWMMG and M2 and is based on conventional, brass cased rounds for the LWMMG. In addition to weapon upgrades, Poly case technology is going to further lighten that load, or better yet, increase the amount of ammunition a machine gunner can carry.”

      So the theory is that poly cased ammo will bring the weight down to feasible. Of course a smaller poly cased round would still allow more ammo for the same weight when a 1700m range isn’t needed.

      • SSD says:

        Yes, poly cased ammo is lighter.

        • Joshua says:

          And poly cased doesn’t work.

          LSAT is of course the exception, but it doesn’t extract. It uses a push through rotating chamber mechanism.

          Poly cased ammunition designed to extract just doesn’t work.

          • Ike says:

            Polymer cased can work fine. You forget that the LSAT has also developed several variants of ammunition beyond the Cased Telescoping polymer, with a standard configuration polymer walled, brass base cartridge case design and an aluminum wall, steel base design. Both offer weight savings over full brass case ammo, and can still be used in a conventional chamber design.

            The Army Marksmanship Unit is using such a design, the polymer .264 USA, right now. It’s listed here in a slideshow from last year by the late Jim Schatz.

            So polymer case is entirely feasible, it’s not the Cased Telescoping ammo of the LSAT.

  2. TominVA says:

    Has there been a capability gap identified by the warfighter?

    • Weaver says:

      As the article states:

      “At the 1700m range, the performance of the M2’s .50 round limits it to use as an area weapon, while the .338NM has been demonstrated to hit point targets at that range. This more than adequately overmatches the Russian PKM which has been a concern for anyone who has found themselves at its receiving end.”

      • TominVA says:

        So there IS warfighter feedback? Or is that just what a few guys at GD experienced?

        • Joshua says:

          Well considering at 1,700M you are severely limited by PID, on top of numerous other failings of the individual soldier.

          On top of that historically 99% of combat engagements have been within 200M, it makes you wonder just what issues soldiers have seen beyond 1,700M for a MG.

          • Rick says:

            I am currently deployed and the nature of our fight in this theater is such that only 1 engagement has ever even approached 200m. On numerous occasions my team has gone up against PKM fire at 1,000m+ with only 240Ls and M107s.

            Throw in vehicle mounted 14.5 and 23mm and we are seriously at a disadvantage. The M2s are great, but we only run them vehicle mounted, which limits their employment options. My experience doesn’t reflect the historical engagements you are discussing, but the .338NM would have been welcome here for sure.


            • Joshua says:

              Sure, Afghanistan is the exception to the rule.

              However throughout modern war engagement ranges have been 200M or less.

              I guess we could completely overhaul our entire military arsenal to make sure we kick ass in Afghanistan at every range possible.

              However we would then have some hard lessons to relearn when it comes to what the past wars against modern nations taught us.

              • SSD says:

                One truth is that we have employed the M2 since WWII in a wide variety of environments. It is anything but a man portable weapon. This changes everything.

              • Bobby davro says:

                Afghan is no longer the exception it’s the norm, look at north and central Africa and the conflicts that are happening there , look at Iraq /Syria and Lybia the old Cold War thought processes need to be rethinked and weapons developed that can operate in multiple environments and in multiple roles and multiple tactical situations and add into that that the real world economics of the situation, if you where a commander and you where told you can have one of the above as a multi role weapon which would you choose ?

              • Rick says:

                I’m not deployed to Afghanistan.


              • James says:

                By that reasoning, a 249 would be fine. The fact is the .338 does things(not just range) the 7.62 doesn’t do , just as the 7.62 does some things the 5.56 doesn’t.

                No one here is suggesting the 240 or M2 go away, just that this would be able to fill a gap in capability,

  3. ODG says:

    This is a waste of money….I can think of 10 things the military needs more than a new machine gun.

    • TominVA says:

      I’m inclined to agree. Only way I can see this happening is first, the Army has to want it, second, it will be a one-for-one replacement of the M240 – that is if poly cased ammo works out and the budget is there. Man, that would be a lot of money.

      • blue says:

        as a weapons squad leader in a light infantry company, my job is the 240b and gun teams. I do belive the army needs a new MG. the 240b is to long and to heavy. that being said. it it is a good platform and works good. i feel it needs a major overhall. the reciver needs to be cut down by 1/3rd and it needs to loose another 4lbs

        • Paul says:

          What unit are you in Blue? The army now issues the M240L with short barrels. Its literally the same tbing you jist said the army needes? Weve had the Limas for years, shit i wad a Limas gunnr in afghanistan years ago

  4. Jon says:

    This is cool, and obviously guns that are employed by a smart unit with smart gunners will kill stuff. It may be worth trying to develop this overmatch (that Overmatch, he’s sooooo hot right now!) for future fights, but I’m not sure how relevant this will be for a light infantry platoon. The ranges described are beyond what a platoon as a whole can be effectively fighting against. Maybe it would be great to fix an enemy with your LWMMG at 1500m and fire a javelin round hopefully using indirect or aircraft to destroy them, but the rest of the platoon would still be well outside it’s max effective ranges and have a ways to maneuver. I’m not saying that I wouldn’t love to have one and sure would figure out how to put it to good use! I’m just not sure this needs to promise to change how the Infantry fights.

  5. Kirk says:

    OK, cool idea. Now, show me how we integrate a third caliber, and what the effects will be on the logistics system, as well as all the other issues with actually fielding this thing.

    The idea smacks of what the Swedes did between WWI and WWII, issuing a separate heavy caliber for their machinegun units. They also issued rifles firing that same round to those units, in order to simplify logistics.

    Personally, I think there are quicker and easier gains to be made with regards to MG doctrine–Like, issuing a better tripod/mount system than that fucking joke of an M192. Seriously, people–The Lafette mounts from pre-WWII Denmark that the Germans later adopted and made iconic were light years ahead of the crap we were issuing, and still have on issue. A trained crew can get a Lafette into operation and delivering effective fire at extended ranges from more varied terrain than you could ever hope to manage with the shit tripods we’ve been issuing–And, despite nearly seventy fucking years of elapsed time, we’ve yet to figure this shit out.

    I’d dearly love to know what gains could be gotten by the simple expedient of building a better tripod/mount, and integrating that. By this time, I frankly thought we’d be mounting our MG systems on things like the PackBot, with integrated night vision, thermals, and all that other shit we could have the gunners operating from behind cover via some kind of fiber-optic cable. Either that, or we could go out and buy up all the Lafette mounts, and actually, y’know, train our guys to match the proficiency of a WWII German Gebirgsjager gun team…

    • James says:

      Can’t argue with the tripod rant, but the additional caliber reasoning would have us still using M14’s.The purpose of logistics is to fill needs.

      • blue says:

        the T&E on the new m192 are not as persice as the old ones. but i do like the fact its all integrated and the weight is nearly half. I use to hate carying the old tripod and sepret t&E as an AG. but the new ones are so much easier, and now as a Weasel i dont mind making my guys carry them. and the reduce weight means more ammo

  6. Josh says:

    No tactical analysis here. That thing just makes me hard..

  7. blue says:

    as a weasel for a light infantry platoon. i got mixed feelings here. For a dismounted kinetic operations, i am not a fan. in iraq we only engage a handfull of times past 500m. in afghanistan we had much longer ranges i think initial contact on average was around 1000m. so i can see the range issue, and i can see the penetration benefits when firing against vics or structures. that being said for pure dismounted patrol operation i would flat out refuse that thing. MGs mean ammo. u need ammo for SBF, lots of it. and your not setting up SBF at 1000m. id rather carry 1000rds of 7.62 then 600rd of .338.

    I can see this being valuable in defensive positions or vehicle mounted. i can even make the argument of using it for dismounts operating out of vehicle where they can run back to them and grab more ammo. then it would be useful.

    my other concern is the logistics. not only the need to now supply 3 different types of linked ammo. but the possibility of getting the wrong ammo. and the shipping weight of it will also provide a great strain on the supply.

    Poly cases are promising but i feel are a loooong way off in the future before they are combat reliable.

    • SSD says:

      You’ve just reinforced the case for the poly cased ammo.

      However, did you ever get .50 ammo when you wanted 7.62 or 5.56? Considering each of them have different DODAACs, the supply system isn’t going to screw that up. The small unit is where those kind of mistakes are going to happen.

      • Blue says:

        I agree that poly be awesome and future. But dont see it happening for a while. Atleast in any combat reliable formate. And the mix up issue. While i agree that will happen at battlion and lower level, i dont want to see an emergency resupply happen and wrong ammo sent due to mix ups or s4 ordering the wrong ammo because they think u got the .338 240s but u got 7.62. I see that happen allot when it comes to ranges where supply will order green tip by mistake rather then copper or vise versa and we cant shoot. Or antidotes from buddies who would get 50 cal ammo for m85 rather then the m2 and could not use it. And from my understanding that was a common issue.

  8. Jon Terhune says:

    The PKM is basically a .30-06, and with our change from M1 ball ammo, to M2 ball ammo, the machine guns lost about 1000 yards of effective fire, so the Garand’s kept the M2 ball ammo and the machine guns went back to the M1 ball ammo. The M1 ball ammo used the 173 grain bullet and the M2 ball ammo used the 150 grain bullet. We could match the range of the PKM by just changing the 7.62 ammo to the 175 grain bullet that the sniper rifles use.