Full auto shotgun

From the WHQ Forum

“Both the SOW (Special Operations Weapon) and its magazine-fed Remington 870 predecessor (bottom) were
products of mechanical wizard Carroll Childers, an engineer at the Naval Special Weapons Center. The 870 mod
kit provided SEAL shotgunners with a quick-change magazine holding 20 rounds. The SOW was full-auto.”

Very interesting. It must have been a fun gun to shoot!

Thanks much to Sven for emailing me the info.

UPDATE: Daniel found the patent for the SOW. Worth reading if you are interesting how it worked.

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.


  • primo capo

    full auto shotgun in ‘Nam?
    for how much of it I know, he is online with the fire concept of the S.O.V
    ” to be the mostest, with the fastest! ”
    ouch! this is the general Forrest’ s motto.
    no jokes, i remember that the S.O.V. overwhelmed the enemies with the maximum firepower…

  • Tyson Chandler

    I think the “Bren Gun” configuration of the S.O.W. is ideal for any magazine fed shotgun. When you consider the size and weight of a shotshell, it must increase reliability dramatically. I wish someone would make a semi-auto version of the S.O.W. it’s awesome!

  • Holy shit, Batman! Truly an “Army of One.”

  • Those two shotguns look EXTREMELY well used. How controllable would an 870 be on full auto?

  • Greetings from Texas
    The only full auto shotgun experience I have had was in the Panhandle by way of a friends old Browning A5 with a malfunction. Several of us tried it before breaking it down to remove the bad part to be destroyed. I found the weapon uncontrolable in automatic fire mode (full auto). If it could be tamed it would be an awsome machine.
    When I was a kid I used to watch a TV show called HAVE GUN WILL TRAVEL. If I remember correctly one epsoide dealt with a guy who had built a Gatlin gun that fired 12 gauge shotgun shells. This was before I got into Cub Scouts and Dad had a hard enough time explaining a gatlin gun to me so cut me some slack if I don’t remember it correctly.
    Having said that, practical or not, a 12 gauge gatlin gun would be all kinds of fun!

  • HeavenlySword

    im betting any such semi automatic would have the same fate any potential AA12 in semi. Just like the USAS.

  • Lance

    Awsome laod with a full auto shotgun and a 12ga rounds with flachette loads. But looks too bulky compaired to a pump.

  • Jim

    Where’s the barrel on the 870? How was the pump mechanism converted to semi auto?

  • Witt Sullivan

    There’s a pre-86 converted Auto-5 somewhere on Youtube with an extended magazine. The bad thing about the Auto-5 is the recoil accelerator that uses a camming action to sling the bolt back to insure ejection. Not only do you have the recoil slamming you, but the bolt gets slung back into you, too.

    Gas operated is the way to go. The USAS-12 was a God gun, as is the AAS-12, but there was a smith that used to tweak Remington 1100’s with an action so smooth, an experienced shotgunner could empty it’s 8 rnd extended magazine in one second, semi-auto. That’s faster than the USAS-12 or the AAS-12’s 350-450 rpm.

    There’s another video of an M-16 upper that’s belt fed and full-auto. The dude built a mount for it. He’s still working on it to get some jamming problems cleared up, but it’s pretty dang cool. It would make an awesome mounted weapon for urban combat or area suppression. http://www.youtube.com/watch?v=iX7vwivR6cE

  • The SOW’s patent is available online.


    I don’t believe that the SOW or the box magazine Remington 870 conversion ever progressed beyond prototypes. The projects were killed by budget cuts when the US involvement in Vietnam began winding down. Both weapons reportedly used the same magazine design. However, there were also plans for a belt-fed SOW.

    The modified 870 remained pump-action, and the specimen shown is missing its barrel. The back stroke of the pump pushed the shotshell backwards out of the magazine onto the conventional shell lifter. From there, it worked like a standard 870.

    However, a full-auto shotgun was briefly field tested in Vietnam: the Remington 7188 Mark I. It was roughly a militarized, selective-fire Remington 1100.

    • Daniel, great find! I have updated the blog post. I am going to enjoy reading that patent.

  • Carl

    20 shot magazine… must be double stack. I wonder whether this would have worked reliably. Shotgun box magazines seem to be 8 rounds at most.

    Also, blow forward mechanism. Very strange.

    On the same page is a picture of this:
    Very cool.

    Witt Sullivan, very amusing video. I particularly like the fact it looks like he’s firing out of his window into the neighborhood 🙂

  • jody

    has anybody fired the AA-12?

  • The general reason why you don’t see high capacity box magazines for shotguns is their length and reliability. Long magazines make it difficult to go prone, and it is hard to get a conventional wire spring to lift so many heavy cartridges over a long distance. Like the 50rd M16 magazines he designed for the SEALs, Childers used constant force springs for the 10 and 20rd shotgun magazines.

    With the magazine mounted above the weapon, the length of the SOW’s magazine no longer interfered with the ability to go prone. In addition, gravity now assisted the feeding of the extended magazine.

  • Greetings from Texas,
    Daniel brought up an interesting point on shotgun magazines;
    The general reason why you don’t see high capacity box magazines for shotguns is their length and reliability.
    Dose anyone here have first hand experience with the 20 round drum for the Saiga 12 Gauge? I know it cost as much as the Shotgun its self – when you can find one. If the thing works it would be worth it.
    I got the .410 Saiga some time ago intending to experiment with it and either sell it or trade it in on a 12 afterwards. After making friends with it there is no way I would ever sell it. It’s great for moving new shooters up to self loading shotguns.