Argentina’s Open-Bolt Pocket .22s: the Hafdasa HA and the Zonda

Originally made by Hafdasa (Hispano-Argentina Fábrica de Automóviles S.A.), the HA pistol is a .22 Long Rifle caliber, semiauto only, open bolt pocket pistol. It was produced in the 1950s, right at the end of Hafdasa’s existence (coincidence?). When the firm shut its doors, a group of employees took the basic design, improved it in a few ways, and creased a new company called Armotiv SA to produce it under the name Zonda.

The Zonda has a floating firing pin instead of the HA’s fixed one, and a creative safety machinist which simply cams the magazine down when engaged. As an open-bolt gun, if the magazine is too low for the bolt to pick up a cartridge, it cannot fire.

Both the HA and Zonda are quite rare today, as not many were originally made or sold.


  1. Checking out the concept, one should wonder what would happen if the bolt fails to lock back after one cartridge is discharged. I suspect slam fire and one empty magazine along with “oh no, I just shot my friend in the knee.” I hope that doesn’t happen with open bolt weapons often…

    • “hope that doesn’t happen with open bolt weapons often…”
      This has more to do with disconnector design and quality. Most sub-machine gun produced before 1939 were open-bolt design and in case of serially produced ones I do not know about complaints of weapon depleting whole magazine against user will. Mechanically it is possible in case of disconnector wear down, but this does apply both for open-bolt and closed-bolt design.

    • The bolt short stroking with lower powered ammunition is a recognised and dangerous problem with open bolt guns.

      You are correct, if the bolt doesn’t recoil far enough for the sear to catch it, you’ve got a run away burst in your hands.

      In a pistol, there’s a truism which says that with an unexpected burst of full auto, the third shot goes up your nose…

      In later Open bolt smgs, some designs incorporated a series of sear notches, so that in semi auto, the sear would catch in whichever notch managed to get behind it

      And example of that is steyr’s plastic handled take on a vz/uzi

      Star had some of the most interesting solutions to the problem of run away bursts with underpowered ammunition, in their 1980s smgs.

      The gevarm open bolt semi auto .22 rifle that Ian reviewed a few weeks ago, had a weight cum spring guide that could be used in the bolt as additional bolt mass for hotter ammo


      Reversed in the back of the receiver as a sort of spring guide (so it stayed in the gun and didn’t get lost; very important that 😉 ), so that the bolt would reliably cycle with lower power ammunition

  2. The South American Saturday Nite Special. A design so dumb the employees wouldn’t let it die of natural causes.

  3. In cyberpunk fiction and RPGs (remember those from about 20 years ago?)they had what were called “polymer one-shot” guns.

    They were cheap, mostly plastic pistols, straight blowback, with ceramic (often smoothbore) barrels, and mechanisms about as sophisticated as these little brutes. Chambered for 5 or 6mm caseless rounds (equivalent to a .22 LR) they were intended to (1) sell for under $20 (or nuyen, or Euros, or whatever), (2) be easily carried in a pocket or purse (you know, for the mall rat market) and (3) provide about one magazine full of shots (10-15 rounds generally) before breaking their mechanisms irreparably (hence “one-shot”).

    After which the brat tossed the busted thing in a trash receptacle and bought another one.

    Some of the more exuberant ones (or ones with less QC) would either accidentally or deliberately empty the magazine in one long full-auto burst at an ungodly high cyclic rate (light bolt or slide, straight blowback, do the math) and then melt their plastic outer casing like cheese on a fresh hot pizza and jam permanently.

    I look at these little monsters, imagine them with no disconnectors (or just ones that don’t work), and sort of see a real-life equivalent.

    BRRRRAAAAPPPP! (clunk)



    • The last part of your discourse was something I brought up earlier. If the disconnecting portion of the action fails, you get a “sputter gun” with no form of control. The ATF found that sputter guns without trigger mechanisms could not be classified as machine guns if the definition of “machine gun” required the presence of a user-operated trigger mechanism to activate the “automatic” operation of the firearm. Thus, the definition of machine gun had to be changed to account for sputter guns, if only because such devices tend to kill people through sheer stupidity of the operators.

    • Sounds like something out of Gibson’s Bridge trilogy. This, or one of his HK police pistols, ‘running caseless through a floating breech;, or the handheld mines that were made by the African Union and shot linked chain.

  4. Can you cock the Zonda with your trigger finger like a Lignose, while aiming? How does the safety drop (or raise) the magazine AND the magazine catch? Too bad he didn’t take the grips off …

  5. In Buenos Aires in business several years back, I had some spare time so I went to the Armas de la Nacion Museum. What really struck me was the number of small arms designed and made in Argentina. Really unique stuff, SMG’s in particular. Worth a visit if you are ever there.

  6. Ian raised an interesting point about fixed fitting pins (firing ridges and firing tits (down pdb! Get down Shep!)) And rimfire.

    I guess that a fixed firing ridge can be at the top of the bolt face if it has a gentle enough slope on its lower face,for the case head to rise up onto it as it feeds.

    It is more usual to have the fixed tit at the magazine side of the bolt face, so that it push feeds the round ahead of it (see Ian’s vid of the late (this year) Casull AM180)

    What the second argentine model
    Along with the Star Z62/z70A smgs (in centre fire) seem to achieve is a fixed firing pin that only gets into its fixed position, in the final couple of millimetres of bolt travel

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