The Marines’ First SMG: 1921/28 Thompson Gun

This Thompson is being sold at Morphys on October 30, 2018.

The USMC had acquired a few hundred early 1921 model Thompson submachine guns in 1926, and prompted the US Navy to formally test the guns. The Navy requested a reduction in the rate of fire, in order to improve controllability and reduce ammunition consumption (20 round magazines go quickly at 900rpm!). Auto-Ordnance happily complied, and Oscar Payne returned to the company on his spare time to modify the gun. He did this my adding a substantial amount of mass to the actuator, and was able to reduce the rate of fire substantially. The Navy subsequently ordered 500 guns, designated the Model of 1928.

Since most of the original 15,000 guns made by Colt were still in inventory, Auto-Ordnance simply overstamped the “1” at the end of “1921” with an “8” and put the new heavier bolt assemblies in the guns, leading to the collector term “21/28 overstamp” for these Thompsons. The lower rate of fire would become the new standard for the Thompson.

By late 1928, only about 6,000 Thompsons had been sold, and by the end of 1938 10,300 had been sold. Of these, about 1500 total had gone to the US government, about 4100 exported, and the remainder to American police and security agencies. Times were not good for the Thompson – it was an expensive military weapon without a war that needed it. Despite the gun’s huge notoriety, it was actually not used in particularly large numbers by the motor bandits of the 20s and 30s, nor in great numbers by the police. While the FBI did purchase Thompsons, they only bought 115 in total, and not until 1935.

This is the second part in a 5-part series on the development of the Thompson…


    • “Gangster Gun”: 1930’s media hype-word used to promote political action. See “Saturday Night Special” in the late ’60s and “Assault Weapon” in the ’90s.

      • To state my view of those straw-stuffed politicians, I must quote a videogame mob enforcer. “You guys are a joke, and here’s the punchline!!” The pen isn’t mightier than the sword if the pen only exists to “control the minds of law-abiding people.” The sword is only the extension of the one who wields it. The same is said of the gun.

        • Citing Adrian Carton de Wiart:
          Governments may think and say as they like, but force cannot be eliminated, and it is the only real and unanswerable power. We are told that the pen is mightier than the sword, but I know which of these weapons I would choose.
          Which is undoubtedly confirmed by his service record. I would not write it here in whole as it would be really long, but I will just say that he was awarded Distinguished Service Order during Great War [which was awarded for action under enemy fire].

  1. With the lock piece leaning under quite pronounced angle back (my guess is around 45deg)it suggests that the resistance to blowback is not really that big. I’d wish to know a bit more about initial experimentation which lead to this particular lock angle. One would think, if angle is less acute, the resistance would grow and thus RoF will be lower.

    This is one subject to consider; another directly connected one is mass of bolt (as increased by mentioned modification and even more). I had Thompson in my hand once and one of things drawing my attention was that surprisingly light hollow bolt. In hindsight, the simplest thing how to arrive more favorable result would be to drop out the lock and increase bolt weight which was the final step in development of this peculiar weapon.

    • I want to point some similarities between history of BAR and history of Thompson sub-machine gun, both were answers to trench warfare requirements

      1. Originally created as automatic rifle (to be operated by 1 soldier)
      2. Later development in direction of turning it into light machine gun
      3. Result: weapon inferior in role of LMG to “full-blood” weapons of this type (like for example Bren)

      1. Though not strictly machine pistol in original form (“Annihilator”) as it was not full-auto/selective-fire variant of self-loading pistol, it is somewhat in-between pure machine pistol and MP18-like sub-machine gun
      2. Later development in direction of making it more MP18-ish (wooden stock, drum magazine)
      3. Result: weapon heavier than already heavy sub-machine guns of 1920s-1930s

      It is interesting that in both cases Europeans in point 2. made step further, namely for BAR: Kg m/37: which featured quick-change barrel
      for Thompson: BSA Model 1926 Thompson:

      • BAR as LMG: both the FN Mle D and the last version by Colt (R75A) featured a quick change barrel as well. The FN D was probably the best BAR for LMG use, limited only by the 20 round magazine. However, smallish magazines for LMGs were not out of the ordinary at the time: the French FM 24/29 had a 25 round magazine and the Finnish Lahti-Saloranta M/26 a 20 round magazine.

        • “smallish magazines for LMGs were not out of the ordinary at the time: the French FM 24/29 had a 25 round magazine and the Finnish Lahti-Saloranta M/26 a 20 round magazine.”
          After some thinking I must agree that small magazines were quite popular in 1930s designs of LMG, beyond mentioned models it can be also found in:
          Breda Modello 1930 (20 rounds)
          MG 13 (25 rounds; also available 75 rounds-magazine for AA aplications), inter-war German (13 is fake designation to make it appear as 1913 design) machine gun, overshadowed by later German development (MG 34) but still in use during WW2
          ZB vz. 26 alias MG 26(t) (20 rounds)
          Mendoza C-1934 (20 rounds)
          SIG KE-7 (25 rounds) Swiss-made machine gun only for export markets
          Knorr-Bremse MG.35/36 (25 rounds) machine gun in limited use by Waffen SS; accept MG 13 magazines

  2. In 1932 my home town in South East New Mexico was visited by Bonnie and Clyde. They were visiting relatives. A deputy saw some guns in the back of their car, and knocked on the door of the house they were in. Long story short, they kidnapped the deputy and drove out of town, letting him go, unharmed, near San Antonio Texas.

    The aftermath was that the city police department thought, what with bandits visiting and all, that they were under gunned so they bought one Thompson. Never to be fired in anger as far as I know. It is in the local museum now. And the deputy later became Sheriff and eventually the police chief.

    • Too bad the descendants of that generation of people of color are now losing their right to vote to a new wave of legal trickery just like the original one in the 1870s. The KKK was not beaten by their victims shooting back, but by the Federal Government temporarily being the product of the weight of their votes after Congress passed laws (now being overturned) singling out right-wing states for that trickery. As of this week, a Native American in North Dakota living on a reservation has no right to vote because, dig it, he only has a Post Office #.

      • Just wait until the state governor gets rocks, fire-bombs, and lots of bullets coming at his house. Laws that disenfranchise voters just because they don’t have mailboxes tend to fail in one way or another. Either the state can offer the Natives free mailboxes or the law must be repealed. Whether the latter option requires picket signs or a hail of copper-jacketed lead isn’t my problem but the issue can’t be ignored forever!

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