Video: SIG Wants You… to Buy an MPX

We’re not sure how old this current MPX video is, but it’s not the one we’ve had before.

We’re starting to see factory SBRs show up but we’re too tied up in Czech stuff at the moment….

And is it just us, or are factory gun videos getting more and more hooah with every iteration?

We don’t have hands on one yet. but we like the idea of the MPX; it’s a good revision and upgrade of the MP5 concept. It makes the best use of advances in materials (modern plastics), ergonomics (M16-sized, for people with normal human thumbs, rather than HK sized, which are suited only for people in the six-sigma zone (99.9999) percentile of pollex protrusion).

Other postwar submachine guns like the Beretta M12S and the Walther MPL/MPK never caught on the way the MP5 did. And all pistol-caliber submachine guns are up against the problem that a rifle-caliber long gun is, for most purposes, more useful. But an MPX SBR seems like it would be a blast as a range toy. We’ll have to get hands on with one soon.


Apologies to all for having an incomplete version of this post up for about four hours this morning. Your humble blog editor is now writing fifty times, “I will check the site first thing… I will check the site first thing…”


8 thoughts on “Video: SIG Wants You… to Buy an MPX

  1. Dave

    No love for the Scorpion? About a grand cheaper, and from your buddies at CZ…

  2. Tierlieb

    You know, the comment in the video about having waited 50 years for this got me thinking:

    1. Have we? Were there not a bunch of interesting 9mm submachine guns? MPL and 12S have been mentioned in the article, Dave mentioned the modern competitor CZ Scorpion Evo. I think about the H&K UMP (H&K updating themselves?) or the Spectre (remembered best for one of the first working casket magazines, iirc).

    2. Why does it feel that I have actually not waited at all? Is the 9mm SMG anything more than a range toy considering what short barrelled AKs and ARs can do?

    3. The T-charging handle is stupid. The only reason for it is that is functions similar to an AR-15. But since there are enough actual AR-15s in 9mm, even as short-stroke piston system, what’s the point?

    4. Incremental updates (barrel change, stock change, grip change, sadly a proprietary rail system, but it seems good enough) are really boring, aren’t they? But considering that Beretta went in the other direction with the Cx Storm, is seems to require some insight. Huh.

    5. Has modularity gone too far? Field-replaceable buttstock options? Why?

    6. What’s the point of a short stroke system in a gun that is going to be run even less before cleaning than an AR-15?

    This is not me ranting. This is not TFB after all ;-)
    I assume there are several good potential answers from the readers here, I just don’t see it.

  3. John M.

    Shooting someone inside your house is unpleasant. It’s even more unpleasant if you do it with a rifle cartridge out of a short barrel. This does NOT matter if you are a cop and have easy access to suppressors (bonus: legal immunity from such fun things as getting rolled over by your local anti-gun DA for defending yourself and finding yourself with an additional federal beef for a judged-to-be-illegal use of an NFA device). But it does matter to the rest of us.

  4. atp

    I haven’t shot one, but People on the Internet who have say the MPX runs dirty, so of course even dirtier suppressed, and with plenty of gas blowback. How’d Sig manage to do that with what’s basically a shrunken piston-operated assault rifle action? And which they market for suppressed use? Something doesn’t sound right about that design.

  5. RSR

    +1 on John M’s comment. 9mm out of a 16″ barrel is only slightly louder than a 22lr. And w/ 140+ gr standard pressure even out of 16″ barrels you’re still subsonic, reducing perceived noise often below 22lr.
    The only real advantages indoors for 5.56 are the faster tumbling (so effectively less penetration) and greater energy and lethality — but w/o a suppressor that lethality comes with more blast and flash, which means less situational awareness once you start pulling the trigger.
    Some of the high velocity 9mm rounds like federal 9bple +p+ fragment extensively at carbine velocity in gel blocks, though less so in drywall… Regardless, 9mm defensive rounds are designed to perform at lower velocities (if needing to shoot at further ranges, unlikely in legally justifiable hd situations), and higher velocities may result in less penetration but more expansion… Though I tend to stick w/ hollowpoints with more rounded noses like the federal 9bp/bple/believe xm9001 canada le spec is in between in velocity (same 115 gr hps on all) or the hornady critical defenses (typically in +p) in pccs for HD to ensure reliable feeding. The hornady’s have extremely controlled expansion as do most modern bonded HPs, though many other bonded hps tend to have more open cavities, flat noses that can cause feeding issues in some weapons.

    Tierlieb #2 — 9mm costs 1/3rd less in brass than 5.56/.223. Yes, 7.62×39 and 5.56 are more lethal, but see John M’s comment. Also, rifles are always more accurate than pistols. And even one handed, you still have 2 point control of weapon. Slings also aid in weapon retention. I really like the compactness and portability of the Keltec Sub2k for instance — with pistol grip mag and 16″ barrel, it’s about same size as 8-10″ barrel 9mm AR with stock collapsed if I recall correctly… One shouldn’t be clearing a house in event of intruder if possible to avoid, but sometimes you have to move through house to secure kids, etc…

    For new shooters , I find 9mm is a great centerfire cartridge and cost effective step up from 22lr/wmr.
    For that controlability/good training base (low blast and flash to not deter from fundamentals) reason, ammo commonality w/ handgun, that 9mm out of a carbine barrel has energy equivalent to .357 mag at muzzle, and that 1k boxed 9mm rounds, more loose, can fit in a 30 cal ammo can — I find myself often recommending a paired 9mm pistol and carbine to friends wanting something to defend their home (and knowing that they’ll only get minimal if any training and unlikely to ever become weapon enthusiasts). (And for precision [being able to account for where projectiles are going in home is key for me in this use scenario], mag capacity, that anyone can shoot/control, and followup shot speed, I also prefer 9mm carbines over shotguns for HD roles.)
    A paired 9mm pistol and 9mm carbine allow both husband and wife to arm themselves for $1k to $1.5k if buying new and from reliable makers. Obviously, one can go cheaper. Add in 1k rounds of ball and 500 rounds of good self defense hps for another $500, and that’s a really cheap insurance policy that covers most probable self defense needs one would encounter…

    If you want a 9mm AR, then get a colt over the MPX IMO.
    MPXs are expensive, mags are stupid expensive at $50+ (though I do wish lancer made mags for the EVO), and I really see no advantage of the MPX’s gas system over blowback as reducing recoil seems to make a significant tradeoff in reliability…
    For an expensive subgun, I’d spend a couple hundred $ more, and go w/ the B&T APC9 — they take AR triggers too and unlike Sig, installing another trigger won’t void your warranty…

    I like Sig pistols and am a fanboy of the W. German guns in my collection. On rifles (at least stateside), they seem to continue to get it wrong or at least not reliable — and I say this despite being a fan of Swiss military rifles as well…

    1. RSR

      *Clarification — 357 magnum out of pistol has same energy as a +P 9mm out of a 16″ barrel. Another interesting stat is 9mm out of 16″ barrel at 50 yards has ~ same energy as the same round out of pistol.

      Looked up Sub2k vs AR lengths. It’s shorter than 14.5″ barrel AR15 w/ stock collapsed and about the same as a 10″ barreled SBR AR15 w/ stock extended…
      Good read on sub2k here:

      To be clear, I think an 8-10″ 9mm carbine barrel is ideal if planning to add a suppressor — if not, I see no reason to go w/ shorter than 16″ or pinned 14.7″ as the reduced muzzle report is a substantial benefit of this caliber — and a true stock also greatly enhances accuracy w/o the sbr hassles while remaining light and compact.

      9mm out of a sub2k also shoots flatter than high velocity 22lrs like minimags and even velocitors. You have to get to light high velocity 22lr loads like the cci stinger shoot as flat as +p 115gr 9mm loads out of a 16″ barrel… Out of a 16″ barrel, 9mm shoots extremely flat out to 120 yards or so. sighting at MPBR at +/- 3″ (6″ total) you can stretch out to 150 yards, but begins dropping quickly after that. (I don’t personally see a need for a pcc in that extended of a role, but worth noting.)

      Lastly, one 9mm cartridge weighs about the same as one 5.56 cartridge…

      I always like to reference this for blast and flash, though if adding 300 blk to the mix, it makes things more complicated…
      “There has been a cultural shift from the 20-inch barrel length in the AR-15/M16 weapon systems chambered for the 5.56×45 NATO cartridge to progressively shorter barrels for the purpose of producing an increasingly more compact assault/entry weapon without resorting to a bull-pup design. Simple usage of these short-barreled weapons has shown the necessity for both sound and flash suppression, the intensity of which (in exceptionally short barrel lengths) approached the intensity of a flash-bang diversion device. This shift toward shorter barrels has resulted in the U.S. Army and Marine Corps adopting the 14.5-inch barreled M4 carbine with a re-design of the 5.56×45 from the 55 grain SS-109 to the 63 grain M855 ammunition to optimize this barrel length. The differing bullet design also necessitated a change in the rifling twist rate from the original 1:12 inches to 1:7 inches.

      Law enforcement and some special operation units have continued this trend by using weapons fitted with 10.5-inch barrels, and there is some misguided law enforcement interest (in these author’s opinions) in the M16 type weapons using 7-inch barrels. Besides the horrendous flash and sound levels, these ultra short barreled weapons introduce significant ancillary issues, including weapon functioning and reliability as well as projectile stability and cartridge lethality.”

      1. Hognose Post author

        The change to 63-grain M855 had nothing to do with the shorter barrel length of the M4 and predecessor carbines. It was the US counter to the Belgian SS109 round meant to have superior effective range and terminal ballistics to the then-standard M193, and it was issued with the M16A2 beginning circa 1982-83.

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