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On the face of it, it looks like SIG SAUER shrunk an AR-15 down to 9mm cartridge length and voila! The new MPX. The gunmaker touts the result as revolutionary. As RF will tell you, this kinda stuff gets filed under “evolutionary” in my book. LEO only? Nope. As Dracon 1201 points out below, the video above shows an MPX C carbine in semi auto only with a 6.5″ barrel and 9.5″ permanently attached muzzle break—making it a semi only 16″ barrel carbine. While SIG’s $1207 msrp P556 pistol isn’t exactly a sales phenom, an MPX might fly off the shelves. Like everything else these days. At any price. Maybe I’ll run into the full-auto MPX at the NDIA . . .

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  1. No Civie? Not true, just watch the video, they have the MPX C carbine in semi auto only with a 6.5 inch barrel and 9.5 in permanently attached muzzle break making it a semi only 16in barrel carbine. LEO market-No, made for civilians-YES!!!!!

    • That brake is the dumbest idea ever. Why dont they just offer 14″ barrels with a normal brake/FH? That brake also looks like a suppressor without a tube.

  2. The MPX is far different from a KT Sub2000, it doesnt fold in half, doesn’t use pistol mags, and i’m sure there is a large price difference as well. Before the panic wasnt their 556 pistol $1k compared to $400 for a Sub2000? God knows how much this will be, but i’m sure it’ll be somewhere around 556 pistol prices.

  3. “…a 6.5″ barrel and 9.5″ permanently attached muzzle break…”

    Lol wut? A 9.5″ muzzle brake for the punishing recoil of a semi auto 9mm carbine? A 16″ barrel or 14.5″ with flash hider/brake wasn’t “Operator” enough? Or was making seperate barrels for the civvie versions too expensive so they made ridiculous muzzle devices?

    • Yeah, the muzzle brake thing is ridiculous. I bet SIG chose to do it that way to avoid tweaking the gas system to work with a true 16″ barrel.

      Does anyone know for sure whether it’ll be sold to the public as a pistol? I think buying it as a pistol and later making it an SBR would be a good way to go. At least it would allow you to avoid that muzzle brake.

      • Look at the end of the muzzle brake. Looks like threads to me. Look at the brake itself, looks more like can baffles to me.
        Add in the fact that they announced cans at AUSA, it seems pretty apparent whats going on.

    • i second that, they would have to have a different gas system for a drastically longer barrel and pistol cartridges probably BARELY have enough power to cycle the gas system as they designed it..

  4. Are SMGs still a growing market? I was under the impression that SMGs were falling out of favor, and that SBRs were taking their place. Am I wrong?

    • In America, yes. However there are a lot of foreign LEAs that carry SMGs as primaries like American cops carry sidearms. You see SMGs like the MP5, UMP, and TP-9 in places like Britain, France, and Germany. India placed a massive order for Beretta MX4 Storm carbines in 2010/11. Pistol caliber carbines/SMGs are still popular in Israel (Various Uzis and pistol caliber Tavors).

      They’re still favorable where suppression is more important than ballistics. (Look at DEGRU using the MP7).

      Right or wrong, there’s still a lot of places that buy SMGs. Most are foreign.

      As for competing with the MP5, well they only sell the 9mm (although I’ve heard those are mostly discontinued) as of right now and support for that is lacking as they’re pushing for the cheaper to produce UMP line. Add in the manual of arms similarities with the AR FOW and its more apparent why this SMG should do well.

      • The MP5 comes in 9mm, .40 and 10mm, though the latter two are only used by LE agencies in the US. The 10mm is primarily used by the FBI in two-shot burst configurations but is being phased out by them in favor of M4 carbines, unfortunately.

  5. So someone at Sig actually thought that a pistol caliber smg, when most militaries and police are moving away from their pc smgs like the Uzi and Mp5 in favor of proprietary cartridge smgs, would be a good idea? To whom are they intending to sell this weapon?

  6. They are suppose to offer this in 357sig which would be much nicer than 9mm. More power in an easier to manage package.

  7. The rock’n sound track just makes it seem so cool… along with the emphasis on “X”.

    Be nice to shoot and own one, but I bet even the civilian version is going to have a price tag in the thousands… not to mention the price of official SIG accessories.

    It makes me sad until I remember how much I love my P226. Mmmm, P226…

  8. Why couldn’t SIG put money into figuring out the barrel/MB on this gun instead of wasting it on their stupid ACP platform?

  9. Anyone else notice how every time they showed the gun coming out of the water, they would cut away to a different angle before they showed it being fired? In other words, did they possibly stage the water test? All the other tests seemed to use one continuous camera angle, although I’m too lazy to go back and verify.

    • Yep, the only time I remember seeing a good water test was HK’s 416 test where the diver had a face shield on in case it did kaboom.

      • It’s the same guy 😉

        Plus, it’s obviously a marketing video showing the types of testing it’s been through vs being documentation of testing.

  10. Its another MP-5 copy. Id say stay with the Original the MP-5SD series is still the best for a 9mm SMG. Though I prefer a M-3 because its .45 AUTO caliber.

    • Other than shooting a pistol caliber, how is it an MP5 copy? Different manual of arms (HK vs AR selector, mag release, and charging handle), different operating system (roller locked delayed blowback vs short stroke piston), different manufacturing techniques (stamped steel vs machined aluminum), different bolt system (fixed bolt vs rotating locking bolt).

  11. The Civilian version “C” with the long handguard and fixed compensator looks like the quick swap out feature of the barrel, bolt, gas system does not look too easy on this version as it does on the smaller LEO/mil pistol versions. Not to mention the early MSRP indication of $1999.99 will probably mean multiple caliber options will get you into the add $400-$500 range per caliber. As to the comment about PDW weapons being in more favor, I think for LEO, that have to consider collateral damage, especially SWAT, this will work better for them. Better defensive round options in a hard hitting pistol caliber that does not create as much muzzle blast concusion in small rooms. Additionally, better subsonic suppressed options which also give’s less of a of chance for over penetration as the 5.56 option does in CQB/CQC.

  12. This will be one of the first pistols that can do a quick change from a pistol caliber to rifle caliber (5.56). By that token you can also go from short barrel to long barrel. From stock (SB15) to no stock. All in mere seconds. And with the MPX-P you’re getting a product closely related to a milspec / torture tested / over the beach capable military/LEO product.

    The modular philosophy lately with SIGs is really cool from the P250/P320 to now these rifles/pistols/PDWs. Take my money!

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