Ten Pound Monkey sent us these photos from the AUSA Expo of the upcoming SIG MCX PDW. The upper receiver contains a short stroke gas piston system with a forward recoil spring, doing away with the need for a buffer tube and allowing foldable stocks and collapsable wire stocks.



SIG are utilizing carbon fiber for the lower section of the handguard, reducing weight while looking pretty nifty, and also in some capacity for the suppressor. Suppressor tubes made entirely of carbon fiber do exist, even for medium sized calibers like .308 Win., but they are very expensive and have a reduced lifespan. It is more likely that SIG are reinforcing steel, titanium or a lightweight alloy with carbon fiber.




Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Karina

    And here I thought the MCX would be a sort of carbine version of the MPX to be released to the public. Bah, oh well. I guess there are other methods of getting a pistol carbine in .357 SIG, but that would still have been nice.

    There are definitely some shared design and ergonomics between this and the subgun, though. I’d still like to have one of these, they seem comfortable to carry around.

    • Tim U

      The MPX is allegedly coming to the general public at some point. It will just have a ridiculous 9.5″ muzzle brake on it to make it a 16″ “barrel” for NFA requirements.

      Now, if you live in a free state you can buy a tube, pay your $200 tax, and presto, integrally suppressed gun. But that’s only for those of you in free states.

      • Rob in Katy

        or when the shit finally hits the fan! I don’t think NFA will matter much then.

        • Tim U

          in SHTF, good luck buying the tube or anything else…

          • bbmg

            Perhaps not “the” tube, but certainly “a” tube will be available.

  • Yo dawg I heard you like carbon fiber…

  • Doopington

    Ultra-want. It’s like everything I wanted from the MPAR short of a bull/thick barrel.
    Though, the price will probably be absurd (like 2500+) and not come with upper-only sales, considering SIG…

  • z

    …so…’s an even more expensive version of the LR-300?