Thompson “Tommy Gun” SMG… .30 Carbine Version

During World War II, various companies and weapons designers vied for the coveted contract that ultimately became the M1 Carbine in .30 Carbine. One of those companies was Auto Ordnance, which did submit a “light” rifle design, but as a “just in case” also developed a .30 Carbine version of their Thompson SMG.

Originally chambered for the .45 ACP pistol cartridge, it took a bit of engineering to bring the Tommy Gun up to .30 Carbine specification. Specifically, a new magazine and receiver was required to handle the longer and more powerful load. From there, various internal mechanical bits were reinforced, but the primary operating action was the same.

The weapon was truly a “just in case” submission to the Army, which was summarily rejected. The .30 Carbine Thompson SMF was nearly double the weight requirement for the light carbine, coming in past 12 pounds, unloaded. Auto Ordnance hoped to win the contract as minimal retooling was required to get the weapon into production.

All the common quirks of the ubiquitous Tommy Gun remained. The magazine release was activated upward, the charging handle was on the top, which reciprocated as the gun fired, and the safety and selectors were in their usual unusual locations.

To see all the details of the .30 Caliber Thompson, check out the video from Forgotten Weapons:

Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • TVOrZ6dw

    .30 carbine in a 12+ pound sub machine gun must be a smooth shooting weapon.

  • TechnoTriticale

    What’s the operating system?

    Since the .30 Carbine is a tapered case, I’m wondering if it can reliably be adapted to either Blish or blowback, and if neither of those, what delays breech opening?

    • gunsandrockets

      Looks almost exactly like the M1928 Thompson, so that .30 Carbine caliber Thompson would still have the Blish-Lock. Perhaps in .30 Carbine caliber the Blish-Lock actually added some useful function, since it clearly was an unneeded complication in .45 ACP.

      • TechnoTriticale

        re: …so that .30 Carbine caliber Thompson would still have the Blish-Lock.

        I’m not sure that solves the problem. as I understand the BL, it’s a hesitation lock, so the bolt starts moving as pressure rises. With a tapered case, if the case moves before pressure drops, gas can leak back at the case mouth. This is going to be a chamber and bolt face erosion hazard and user annoyance.

        Straight-wall cartridges, and necked ctgs with straight necks don’t have this problem. The M1 and M2 carbine avoid it via delayed bolt engagement. The op rod is what first moves (and only when the bullet is already near the muzzle).

        Perhaps the Army didn’t bother test firing the .30C Thompson because it didn’t pass eyeball engineering examination.

        The tapered case of the .30C, by the way, is a bit of a nuisance for reloaders. Cases have to be lubricated for resizing. There’s no point in a carbide die for the job.

  • JustAHologram

    Any chance they will reintroduce a semi auto version soon?

    • AC97


  • Richard

    It could have been an attempt similar to the beretta m9a3, saying instead of this entire new program that might not turn up anything here’s an updated gun that can sort of fit most of your requirements at a possibly significantly lower cost to an entire new weapon.

    • marathag

      Though ‘Auto-Ordnance’ and ‘lower cost’ really weren’t said in the same sentence much before/during WWII

      • Richard

        I was thinking like some sort of sales pitch that they could/would have said if the gun got more than 30 seconds of attention.

  • Darren Hruska

    It’s always refreshing to see a “heavy submachine gun,” a term I would use to describe a pistol-caliber automatic weapon of considerable weight/bulk (such as the LAD and Hellriegel M1915) or one of a “magnum” pistol caliber (such as the MP5/10, 9x30mm Gepard, Thompson Model 1923, and perhaps now this). You don’t see such a thing very often. Although, many still debate whether .30 Carbine is more-so along the lines of a pistol or rifle cartridge.

  • CharlesH

    How can I replace my car with this?

  • Richard

    I wonder if the people who made wolfenstein: the new order knew about this Thompson

  • lowell houser

    Just a thought, but wouldn’t that make this the first assault rifle? It uses an intermediate cartridge, has full auto. Was there something earlier?

    • Zachary marrs

      Federov avtomat, and some would argue that the m1 carbine was quite close

  • Wolfgar

    Does this mean the 30 carbine cartridge is a pistol round instead of an intermediate rifle cartridge, voiding the M-1 carbine from the assault rifle list? I doubt the 7.92X33 could have been used in a Thompson blow back SMG.

    • Wolfgar

      30 Carbine : 40,000 PSI
      7.62X39 : 45,000 PSI
      5.56 : 55,000 PSI
      7.92X33 : 49,000 PSI

      • The Brigadier

        7.62 X 51 : 62,000 PSI
        .308 Win : 71,000 PSI

  • jerry young

    I’ve always wanted a Thompson and now I’m adding this to my list, now if someone would only make one in 5.56 I’d want one of those too!

    • L. Roger Rich

      I’ve got a semi-auto Kimber / Thompson Tommy Gun . 50 rd drum. The are only about $1300. at Buds guns. Free Shipping.

  • Old Vet

    I was wondering if this is the only example? Wow, would love to own this one though. Darned old museums have all the luck…..

    • Gunner4guy

      If you look around in dusty, dirty closets, especially in a ranch in SE New Mexico, you ‘might’, just might find a Thompson chambered in .38 Super. Don’t know where this old guy got it, how or where it is now but it was a trip to shoot. If I’d known then what I know now….
      Been told there weren’t all that many made, apparently made for police use…. like under a thousand. Not sure how true that is tho…

      • Old Vet

        Sounds like an adventure just waiting to happen. My trips are spent going to China with the little wife, not much gun stuff there except in the museums…haha

        • Gunner4guy

          College roommate invited 3 of us out to his Grandpa’s ranch to help thin out the wild dogs tearing up cattle. Good grub, a few brews then the next morning we went out in some pickups and hunted down a couple of packs… too late for some cattle we saw though. Two M3’s, a .45 Thompson, this .38 Super Thompson and a couple of old rifles. Bouncing around in the trucks, had a blast and got to burn up a LOT of ammo. More interested in shooting then, not the Thompson. Have no idea if the subguns were legit or not…, some things you just don’t ask a generous host.
          Couple years later Uncle Sugar provided me with all the guns, ammo and targets I could want but I’d still like to have that old chopper but prob can’t afford it now.

  • I believe that qualifies as a thomas gun