Evelyn Owen’s homebuilt .22 SMG

Here are some pictures of Evelyn Owen’s homebuilt .22 submachine gun made from bits of scrap steel and .22 short rifle parts in his younger years. Some time after a test firing session at a local beach, it was discovered carelessly left against a garage wall by his neighbor, who fatefully happened to manage the Port Kembla plant of Lysaght’s Newcastle Works. Impressed with his simplistic design he arranged for him to be transferred to the Australian Army Invention Board where he began work on what would later became the Owen Machine Carbine.

The design contains a hilariously simple trigger made from a piece of spring steel which also catches the end of the bolt handle. It’s magazine is interestingly powered by a large flat coil spring. Can anyone decipher this component’s workings further? By all accounts it functioned quite well.


Edit: A commenter has spotted the magazine wheel as being made from an old harmonic balancer / crank shaft damper.







Bolt and trigger operation:



 Australian War Memorial site






  • Ken
    • Giolli Joker

      I don’t think you have to load each round manually, if the magazine spring is released by the movement of the bolt, another round is ready to be fired, unless you release the trigger, locking the bolt.
      I believe there’s no ejection as well, simply the spent cases are left in the cylinder.
      It’s a “full-auto, open-bolt revolver”. 🙂
      My only worry is that the strength of the spring might outrun the bolt making it hit the cylinder walls or “jumping” a round, but if it’s timed correctly, it should work.

      • Ken

        I meant you have to load each round manually into its chamber on the cylinder, just like a revolver. However, you won’t have to manually eject each empty like on an SAA or Streetsweeper, because the open bolt design does that for you upon firing.

        • gunslinger

          that makes sense

      • bbmg

        Surely there’s a ratchet mechanism which indexes one round at a time per bolt movement, otherwise it’s literally hit and miss. The holes drilled in the magazine look fairly evenly spaced, though I’m guessing there is a bit of tolerance in the chamber diameter in order to ensure correct alignment.

  • El Duderino

    OK…ATI clone made out of pot metal and steel stampings in 6 months?

  • DiverEngrSL17K

    For a first-time, home-built amateur effort, it is all the more impressive, especially considering the restrictions and materials shortages of the time. Owen’s enormous talent appears to have been grossly misjudged and under-estimated by some. The later Owen SMG earned a well-deserved sterling reputation for sheer reliability and balanced firepower and accuracy under the harshest battlefield conditions imaginable in the South Pacific. it was not a particularly attractive-looking gun nor aesthetically-pleasing in most ways imaginable, but if ever looks could belie pure functional efficiency, this was it. And that was what mattered in the end.

    • bbmg

      Pretty is as pretty does 😉

      • DiverEngrSL17K

        Also true :)!

  • Fruitbat44

    That is a really interesting bit of firearms history.
    Hmmm . . . so effectively it’s a clockwork submachine gun? That’s got a real steampunk vibe to it. 😉

    • bbmg

      Well, US forces are currently fielding a clockwork grenade launcher…


    • ThomasD

      Yep, it’s a full auto revolver. The reciprocating bolt slam fires, ejects the empty, then releases the cylinder, which advances under spring tension to the next detent position.

  • bbmg

    Why can’t I hold all these submachineguns?


    Maybe Ian McCollum can shed some light on the inner workings of this fascinating device.

    • DiverEngrSL17K

      Because the rest of us are too busy elbowing you aside for the privilege of doing the same :).

      Jokes aside, great comment, bbmg — We had a pretty lively discussion on FW when Ian M. posted an article on Evelyn Owen and his SMG’s sometime back, complete with the same photograph, to the best of my recollection.

      And many, many thanks to the TFB editors and staff for being understanding and open-minded enough to allow informational exchanges like this among all of us!

  • noob

    hmm. a thumb trigger.

    I wonder if a thumb trigger is easier to press without disturbing sight picture than the trigger finger trigger.

    of course I can see a ND in the works if you accidentally brushed the unguarded thumb trigger against anything.

  • schizuki

    Dulce et decorum est pro patria construi armas.

  • derfelcadarn

    The more of these kind of articles I read the more I realize that the individual and the American People will NEVER totally be over come. Molon Labae Sic Semper Tyrannis

    • BryanS

      Only if they know how to build things….

      • wetcorps

        Yeah, it really isn’t as easy as it seems if you want something that has some degree of reliability and could actually be used in a fight 🙂

    • Kiwi

      Owen was Australian.

    • Josh Reashore

      Molon Labae (sp?) Sic Semper Tyrannis…

      “Come and take thus always to tyrants”???? Need to work on the ‘ole latin a bit? Thanks for posting, it’s nice to have a good Saturday morning laugh over an ignorant rube….

  • undeRGRound

    LOL, didn’t anyone else notice that the revolving magazine was a harmonic balancer off of a crankshaft? Cool arrangement…

    • bbmg

      Well spotted!

  • Russ

    It’s a big revolver with a clock spring driving it. That is not a mag, it’s a cylinder. That is why it’s made from a harmonic balancer-solid iron/steel. Load the cylinder, wind it up, and let her rip. That’s what I see anyhoo

  • derfelcadarn

    Any idea of the rate of fire with this ?

  • Jenny Everywhere

    The trigger looks similar to those used on early crossbows.

  • Doom

    and today in both Australia and America A man would be imprisoned for making such a device. shameful.

  • I think the writer means “simple design,” not “simplistic design.” “Simple” and “simplistic” are far from being synonyms.