Tactical Tailor

SOFIC 19 – SIG SAUER Exhibits Next Gen Squad Weapons

In a surprising move, SIG exhibited their final prototype candidates for the US Army Next Generation Squad Weapon program which seeks to replace the M4 Carbine and M249 Squad Automatics Weapon with a new family of 6.8mm* Weapons which are lighter, yet feature a longer range and more lethal ammunition capable of defeating sophisticated threat body armor.


There are currently two Army efforts underway simultaneously. Both are leveraging an alternative form of procurement referred to as Other Transactional Authority, where Prototype Opportunity Notices are issued to industry and multiple candidate technologies are quickly developed and assessed. The initial round of the multi-phased, first PON to produce a Next Generation Squad Automatic Rifle to replace the SAW comes to a close soon. It includes a requirement for a 20% reduction in weight over legacy brass cased ammunition, but in 6.8mm.


There are currently five companies, delivering six candidate weapons to the Army:
W15QKN-18-9-1017 – AAI Corporation Textron Systems
W15QKN-18-9-1018 – FN America LLC. (Design 1)
W15QKN-18-9-1019 – FN America LLC. (Design 2)
W15QKN-18-9-1020 – General Dynamics-OTS Inc.
W15QKN-18-9-1021 – PCP Tactical, LLC W15QKN-18-9-1022 – Sig Sauer Inc.

Senior Army leaders are expected to fire the weapons next month at Fort Benning in addition to a formal evaluation to determine which candidates move to the next phase.


A second, more ambitious PON for Squad Weapons is just beginning with a requirement for both SAW and Carbine replacement as well as ammunition. SIG informed us they plan to submit the same belt-fed Machine Gun along with their new, fully developed Carbine.

It’s important to note that although the program calls for replacement of the current 5.56mm NATO M4 and M249 in the Rifle Squad of Brigade Combat Teams, this is a .30 class weapon. If everything goes as planned, the Soldier will have an improvement over not only their 5.56mm weapons, but the 7.62mm NATO ones as well such as the M240 Machine Gun.

Previously, SIG had shown their 338 Norma Mag SIG Light Machine Gun at both AUSA and SHOT Show as well as a 6.8mm Carbine Concept called MCX Medium Range, during AUSA. Their Next Generation Machine Gun candidate is very much a smaller version of their SL LMG.

These latest revelations show a much more mature design.


The Machine Gun weighs in at 11.97 lbs, while the Carbine is 8.1 lbs with no Optic or Suppressor.


One of the concerns of the more to the 6.8mm cartridge is recoil impulse. Like with their 338 NM-class weapon, SIG has incorporated a recoil mitigation technology into the Next Gen belt-fed. This brings the recoil in at 2.8 lbs while an M240 in 7.62mm has a Recoil impulse of 13.1 lbs. Considering they are seeing a muzzle velocity of over 3000 FPS for a 16″ barrel, this is impressive. The Carbine on the other hand is delivering 2850 FPS with a 13″ barrel.


As you can see, the optic isn’t mounted to the feed tray cover. Additionally, the weapon can be set up for left or right feed and loading is as simple as inserting the belt into the cover.


The Carbine boasts an interesting feature. It incorporates both a side folding non-reciprocating charging handle and an AR-style charging handle above the boat carrier group.


This is so the weapon can be charged or immediate action drills implemented without the shooter moving his head from behind the weapon.


The side charger is also not operational when the collapsible folding stock is in the stowed position. Obviously, the side charging handle is not ambidextrous, but the other controls are.


As part of the program, SIG has also introduced a new three piece construction hybrid ammunition. It features a Brass case, Steel base and an internal clip to connect the two.


So far, they have manufactured 40,000 of their 6.8 x 51 cartridge at their plant in Arkansas and are working on an additional 60,000. Due to its construction, the hybrid ammo offers increased velocities over standard ammunition in the same caliber and can be used in all current weapon systems, unlike some next generation ammunition proposals.


As the final Army requirement begins to coalesce, expect to see a Designated Marksman Rifle variant of the Next Generation Carbine as well. This, combined with the increase of performance of 6.8mm over 7.62mm signals the eventual end of 7.62mm weapons in the close combat formations of the BCT along with 5.56mm.

*Editor’s note: This new cartridge is not the 6.8 SPC looked at by USSOCOM a decade ago, but rather something completely new, with performance close to .270 win short mag.


28 Responses to “SOFIC 19 – SIG SAUER Exhibits Next Gen Squad Weapons”

  1. Brendan Fries says:

    An interesting design but NATO would hate us for this. I have a hard time seeing this happening outside of dismounted combat arms when many non-shooters struggle to qualify with the 5.56 as is. One common round for all dismounted small arms would be great though, but I somehow see this as less likely considering the USMC has already switched away from the SAW and seen success.

    • Moshjath says:

      The marines fielded an improved Pistol, the M9A1, and that had no impact at all on the Army’s decision to pursue the MHS program and field the M17 and M18. The Army’s pacing threat as they see it is achieving overmatch against plate wearing near peer Infantry, and they want an intermediate caliber cartridge in 6.8mm leveraging the improvements that you see in ammunition such as M855A1 and M80A1. Plus the current fiscal environment is ideal for the program. Army doctrine still employs a belt fed SAW in a 9 man squad and shows no sign of changing that…the weight savings with these prototypes will be much appreciated.

      • Brendan Fries says:

        True, but I somehow doubt the DoD will be ok with one branch fielding a different caliber small arm than the other three. The SAW in the 9 man squad concepts has worked so far because of weight savings with the 5.56 and we will see if it continues with a heavier round.

        • Seamus says:

          Marines still use 12 Man squad and have basically stopped using the M249 and are currently in the process of phasing it out.

        • SSD says:

          Everyone is onboard.

    • Seamus says:

      I don’t think the intent is for NATO to adopt this rifle or round. The US and NATO are falling out of love with each other ever since the EU decided to build their own Army and Navy that is designed to fight the US as well as Russia.

      • SSD says:

        Where is the EU Army?

      • ArmorGuy says:

        The EU has tried and failed to adopt a common military on a couple of occasions. That is a step towards federalization and a loss of sovereignty that the member states are unwilling to cede. If the EU is closer to what the US was under the articles of confederation than it is under the constitution.

  2. EODMadBomb says:

    I like the idea, but it sure feels like there are another 3 or 4 upgrade initiatives going on at the same time, for the same weapons.

    Wouldn’t it be better to concentrate on one and get it right?

  3. Hodge175 says:

    I will give it to Sig they are one of the most innovative gun companies in North America right now. I would love to get some trigger time on these weapons.

  4. Joglee says:

    I bet that barrel life is fun.

    • chris says:

      I’m sure they will likely use chrome lined barrels which greatly increases barrel life. I doubt they would adopt a round for every day use that burns out barrels much faster than 556 0r 7.62 rounds.

  5. mark says:

    The LMG sounds extremely impressive – 12lbs, with substantially less recoil then a M240.

    Given the similarity in the sizes of the cartridges, with the 6.8 LMG be backwards compatible with 7.62 and 6.5 Creedmoor?

    • SSD says:

      Yes, it can be configured in any of those calibers.

      • mark says:

        Awesome. I think SIG will have a lot of interest in that LMG then beyond the 6.8 contract; to my knowledge thats the lightest 7.62 lmg in the world. Factor in the recoil mitigation and modern optics mounting/ergonomics, and its really a great package.

        Any indication of what they’re using for the barrel? I imagine something like the flow formed cobalt / inconel might be required to keep up with the new 6.8.

        • Jake says:

          Forgive my ignorance, what is the flow formed cobalt barrel you’re referencing? Do you happen to have a good source for further reading?

          • mark says:

            Hi Jake,

            Yes, there are two documents that cover it. I’m not linking them, because I think links sends the reply to auto-moderator.

            You want to google ‘Flow Formed MK48 Barrel,’ it should be the top result, a PDF on ndiastorage by Armstrong. Then the more technical paper is ‘Flow formed M240 Barrel’ which is a DTIC PDF. Both are fascinating documents with lots of interesting stuff.

            From the MK48 PDF:

            “ARDEC and ONR have been developing High Performance Alloy Barrels
            for M240 Series machine guns to avoid the need for spare barrels.
            • ATI Flow Formed Cobalt Alloy Lined Nickel Alloy Barrel exceeded 60K
            rounds of life under standard firing schedule in the M240 series.”

  6. Ton E says:

    I can’t believe the Army is going to the 6.8 SPC!!

    Sarcasm off…..

    Had to say it before someone commented about it without reading the editor’s note.

  7. Duncan_m says:

    Does anyone know what recoil mitigation techniques they’re using for the LMG?

    And is the 6.8×51 just a necked down 7.62 NATO case or is it fatter? The pic comparison makes it look fatter. Is that how they got the extra velocity, besides loading it hot, with hybrid maybe alleviating primer pressure issues?

    • Sommerbiwak says:

      I do not think it is fatter, it just looks as if, beause the shoulder angle is different from the .308 and the 6.5 Creedmoor next to it. Sooooo… they reinvented the 7mm-08 wildcat? Those .2 millimetres really do not make much of a difference. I hope you cannot chamber a normal 7,62*51 mm in a 6,8 barrel.

      Those hybrid cases, are that aluminium case heads with a brass body?

      • Seamus says:

        I am not that great at math but 7.62-6.8= .262mm. Then add a grain weight change and a significant change in bc and you have a whole new round.

        … Just saying.

  8. Vman says:

    A quick plugin into the powley computer tells me this cartridge burns at 80 kpsi-ish. Oof.

  9. ArmorGuy says:

    Did I misunderstand the article or is the a requirement for the ammo to be lighter as well? If so how much lighter is SIG prototype over a fully brass munition?

    • SSD says:

      Lighter Ammo, 20% lighter and theirs meets the requirement.

      • Database says:

        My first thought is 20% lighter than what? 20% lighter than 5.56? 7.62? 20% lighter than a convention version of itself? 20% lighter than 12 pounds of lead? (ok that’s being more than a little flippant, but you get that idea) Just seems like kind of a nebulous claim.

        Guess I am just wondering how many rounds of this new ammunition could be carried for the same weight of the standard 210 of 5.56.

        • joglee says:

          20% lighter than a comparable cartridge, so 20% lighter than 7.62 nato. It will be heavier and bulkier than 5.56.

          • joglee says:

            A M855 cartridge weighs 190 grains, the bullet on this round alone weighs 135 grains.