TX-12 Underbarrel Shotgun

Ten-X Tactical has developed a lightweight underbarrel shotgun for M4/AR-15 firearms. It can either attached to a underbarrel picatinny rail, or it can replace the bottom half of an M4 handguard.

7.5″ barrel model
TX-12 with 10.5″ barrel

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.


  • Hmm. All that torque on the barrel seems suspect. I worry that it would screw with the barrel.

    • Joe Schmoe

      Anymore than an M203 would?

      Could be you’re right, but I doubt the recoil is enough to bend the barrel.

      • M203’s don’t hook up to the barrel or the rail. They have their own heat-sync/hand-guard that’s custom built to manage the recoil/torque and force it towards the back of the barrel where the rail hooks up.

        That being said, the bottom photo seems to have a mount which focuses the load much like an M203.

        I’d never use something like this on a rail unless it was seriously vetted for, since that recoil could cause some serious damage to the rail, but as a breaching charge it’s a pretty nifty idea

      • Joe Schmoe


        I remember the M203’s in my unit have a part that attaches to the barrel, similar to in this pic:

        But I would be the first to admit that I don’t know how the M203 recoil is taken care of, so I’ll take your word for it.


      • Yeah, that’s pretty much what I’m talking about. I guess I just mentally blanked on the hook-up in front (my bad). In either case, the majority of the force is directed at the back of the mount so the torque on the front of the barrel isn’t that bad

    • Jeff

      I’m more worried about the picatinny mounted one:

  • Peter

    Are these sorts of things military/police only?

    • Flounder

      They would be an SBS for sure so that adds the 200 dollar tax stamp meaning there is not much of a marker for it with civilians.
      Most likely it is military/LEO only but it could be made available to civilians.

      • SpudGun

        Yep, if you had the right stamp you could get one or something similar. Why you would want or need one is a mystery to me, but knock yourself out.

  • If it works, I want one…really bad!

  • Ed

    I’m guessing it’s a single shot only? I see this geared more towards door breaching then any tactical engagement.

  • Andrew

    I’ve been kicking around the idea for a muzzleloaded smooth bore under the barrel for some time… Can even fit 3x20ga barrels in the space of a 40mm tube, but I can’t figure out why I’d want a shotgun under my rifle.

    • Riceball

      You use it for skeet/trap shooting, if you miss the clay in the air you can quickly engage it on the ground with the AR. ๐Ÿ˜€

  • Bman

    Single shot is useless. You need at least 3 for breaching.

    • Other Steve

      On a glass door? Still need three? How about on a padlocked door? Still need three? On an inside door? Three?

      You need three to take the hinges of a door with a good deadbolt or an unknown lock type.

      Don’t be so closed minded. That’s not me defending this thing, it’s ugly as all hell, but it’s possible to only need one shot sometimes.

      • jdun1911

        You need at least two shot. The first shot might not be enough.

      • PLUS

        Only one shot in breech still not fit to most combat situation,
        isn’t it?

      • El Freddio

        @ PLUS
        Should use at least two for most doors.

      • Bman

        Why would you need even 1 for glass? I can see a padlocked door, but when do not plan for the worst! Would you go into battle with a single shot rifle? It’s not closed mind to be prepared.

  • Ryan

    according to their website “The TX-12…is the latest product release for law
    enforcement and military applications” “The TX-12 is the industryโ€™s first
    and only underslung, double action, ambidextrous, 12ga shotgun system that maintains Primary Weapon Readiness (PWR). Weighing less than 2.2 lbs” “[the tx-12] accepts … 3 inch 12ga magnum rounds, and can also fire all forms of less lethal 12ga rounds”

    • fw226

      Interesting. Hadn’t thought about less-lethals – I can say there are times that would be nice, although it’s always a little worrisome to me to mix lethal and non-lethal.

  • clark

    Even if some situations only require one shell, how dumb would you feel when one shell doesn’t work and someone has to switch to a real shotgun and finish up. Just mount a sawed off over/under down there. You would have two and reloading is a snap. Seriously, no one would rely on that thing.

    • MC K9

      It’s intended application probably wouldn’t be defensive application. Breaching barricaded doors comes to mind.

    • Komrad

      Reloading an over under or side by side break barrel would be difficult while it is attached to a rifle. Plus, you’d either be ejecting into the barrel/handguard or at the mag well, depending on whether it was mounted by the barrels or the action/grip. Maybe a break action that broke sideways would work.

    • Entropy

      I do wonder why nobody I know of makes undermounted double-barrels. It would be so simple in design and as light as it’s possible to make a shotgun. An undermounted semiauto is 50% working parts and 50% barrel/magazine. Why not cut that down a bit?

      You could either put it on a slide-forward action like the M203 or a swing-out one like H&K grenade launchers, which is basically a regular break-open action on its side. Either is fine but I suspect the M203 style would work well as well as being smaller.

      There you go, you have two shots for a fraction of a kilo’s weight. It sits nice and flat against the foreend, and you can put a proper handguard on the bottom of it so you can actually hold onto it (unlike the TX-12 pictured).

  • me

    This is like the one application where Metal storm would be useful
    3-4 shots, one barrel
    Where is their product?
    I’ve seen video of the prototype standalone model

    • Graham 1

      I agree, the metal storm holds 5 rounds, is lighter than the Masterkey and M26, and is a similar size to this thing. Only potential problem i can see is that the Metal Storm uses non-standard 12 gauge ammunition, and I’m not sure how expensive or effective it is.
      Does anyone know?

  • Not to rain on the parade here, but Red Jacket has a underslung shotgun from sometime ago. It was actually posted here on this blog!


    • Sian

      That’s not very lightweight.

    • Komrad

      Sorry to rain on your parade, but there have been a multitude of underslung shotguns over the years. Remington 870s have been underslung for years. If you really want to get technical and pedantic, there have been shotgun/rifle combo guns for much longer still.

      Red Jacket did not invent the concept, nor did they do anything particularly special or innovative. They took an existing weapon, shortened the barrel and gas system, removed the stock, and hooked it to an AR-15.
      It was cool, but not that interesting as far as having a novel design.

    • Mgregg85@gmail.com

      Those retards can claim that they “invented” the Masterkey but they are decades late to the party.

  • Z

    Good luck trying to sight both at 100 yards

  • Matt G.

    First rule of marketing: don’t make your product look retarded.

    • Other Steve

      Is the second rule to SHIP PRODUCT? ๐Ÿ™‚

      • jack

        Third step… Profit.

  • West

    No thanks, ill hold out for the under-slung chainsaw.

  • Derek
  • D

    I wonder if/how you reload it in combat? I do like the exposed hammer, and i do like how light it is, though.

  • It looks like a great tool for operators who are moving in and out of houses a lot. The only thing I might have a concern with is the accuracy at longer ranges. Overall a great idea.

    • Seamus

      i imagine that is what the AR attached to it would be for

  • song tao

    PCBAR (practical curved barrel assault rifle).
    I have finished the dream up of PCBAR (practical curved barrel assault rifle), finally, have cracked a 66-year-old mystery – the technical bottleneck of the curved barrel MP 44 Assault Rifle on display in our Second World War gallery, this is an ideal gun for urban combat for looking around the corners of buildings too. You have not heard of it in your dreams, but this is real and trusting. The PCBAR is a “revolutionary weapon system that enables military and law enforcement to effictively observe/engage targets from around the corner/behind cover without exposing any part of the operator’s body “.
    Unique curved barrel technology:
    You can shoot straight ahead, or select to shoot around shelter, The PCBAR (practical curved barrel assault rifle) may be named after ShelterShot, CornerShot or Safestshot etc. PCBAR is different in approach but equally satisfactory in result compared with the curved barrel rifle appeared in the second world war. Various deflecting troughs and curved barrels had been tried with a number of infantry weapons by many countries, finally, no one was successful. It was found that bullets fired through curved barrel generally fragmented due to the stresses involved, the curved barrel device has proved something of a technological dead-end.
    I havd found a method to resolve the puzzle of bullets turning into fragments in curved barrel, Many people have expressed surprise or disbelief that a firearm can be made to shoot around corners; yet this is precisely what the unique and intricate curved barrel technology enables this weapon to do. The unique curved barrel technology was the fruit of experiments, To resolve the problems of bullets turning into fragments in curved barrel, i have made experiments for hundred times.


    • MT BC

      Get out of here.

  • SGB

    Like all firearms it has its uses. I’d like to shoot one.

  • Big Daddy

    One round does not make much sense unless it was a truly specialized projectile like a rifle grenade or the M203 and other types of 40mm launcher or even the 37mm flare guns. But a single round 12 gauge, that makes no tactical sense to me. I could see adding a revolving magazine like the Milkor 6 shot M32 40mm GL.

    Maybe a 6-8 round cylinder in there but a single shot????? I tried to think of a reason for having it. In any tactical situation I could think of I would just plain like to have a short barreled pump gun with specialized ammo for breaching or other use in a holster or hanging at my side.

    It kind of looks like 2/3 of a M26.

  • John

    Knights Armament Company already did the MASTER KEY, then Red Jacket reinvented it on Sons of Guns, its a niche weapon, that has already been done correctly by KAC. Unless it was made under specific contract, I don’t see the point.

    • Rjp

      how much does a sbs m870 weigh again? how about a saiga 12? both are pretty damned heavy, a bit much attach to the front of your rifle. which is why most entry teams carry a standalone shotgun rather then the masterkey, or and kinda laugh at

  • Ivan

    When everyone is thinking alike someone isn’t thinking…

    You guys are slightly missing a valid idea. I’m surprised no one thought of over penetration… Pull your heads out of the sand and be more open minded; This under barrel shotgun would definitely have a place in some military / LEO apps..

    Scenario – You ‘re about to engage a Bad guy in front of an unforgiving backdrop. (i.e onlookers / innocents /traffic etc..) so you fire a .223 or 7.62×51 round through him and it goes through and hits a guy 100 feet away in the leg… when you could go to the shotgun with minimal effort and put a slug or #2 into him and that’d be enough to stop the threat.