Dual Cycle Rifle

The Dual Cycle Rifle was a revolver based weapon that was designed to fire a three round burst at a high rate of fire from a single barrel. 4,900 rounds per minute! The inventors noticed that conventional automatic weapons suffer from many complications. Too many oscillating parts and springs surging can induce malfunctions if you increase rates of fire. To eliminate this handicap, they opted for a cylinder design.

Here is the patent for more information.


Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at nicholas.c@staff.thefirearmblog.com


  • LCON

    looks like a steam punk assault rifle

  • Mystick


    • Max Popenker


  • IXLR8

    It has a design philosophy like the AN-94 Which only has a rapid 2 round burst. There does not appear to be a magazine. You have to load the chambers each time?
    Is it a single barrel 3 shot mini-gun? Show me a 3 shot group, I may become a believer.
    So many questions….

    • guest

      Although I take the following statement with a whole shovelful of salt – the AN-94 is claimed to shoot two bullets in the same hole at distances shorter than 100 meters, which supposedly up-rates its armor penetration beyond level IV. Again, with a shovelful of salt that is a *theory* worth considering. IRL more likely a higher efficiency due to not 2 bullets 1 hole, but 1 target 2 bullet holes via level III and less protetction, using AP rounds, at the expense of one aimed shot and one perceived shot due to high rate of fire.

      The revolver mechanism does however hold a “treasure trove” of advantages as well as disadvantages. The latter are obvious – mechanical complexity, limited application (LMGs and larger), limited feed mechanisms etc.
      The advantages are however impressive – even the ShKAS machinegun and the latter Ultra SHKAS and SN were all capable of usually “gatling only” rates of fire, by using either full revolver mechanisms or at the very least a revolving feeder/unlinker that all help push much more rounds via the same single barrel.
      I am guessing that combined with a lafette mechanism (like on AN-94), a revolver cylinder to push at least 4000 rds/s if not more, in a single short burst that original AN-94 claim may hold water, but by that time the rifle will become more and more like an LMG than an assault rifle, with all the negative consequences – weight and complexity being the foremost – as a result.
      So IMHO this revolver system is limited to LMGs and beyond, just too much fuss that can be circumnavigated by simply shooting a more powerful cartridge *once* trough a conventional rifle, than shooting several from a rifle overly complicated.

      Kudos to TFB, this site can use more articles like this as a distraction from the “regular” firearms!

      • Max Popenker

        actually revolver system worth effort only in automatic cannons in 20-30mm caliber range, where it was successfully used many times (see US M39, ADEN, DEFA etc)

    • Geodkyt

      Magazine on the illustrated rifle sticks out the left side of the reciever.
      It’s that square shaped box you see in teh disassembled pic.

  • Canthros

    4900 rounds per minute, three at a time, from a fixed cylinder.

    This is a brilliantly stupid idea, and I want one.

    • Geodkyt

      Keep in mind, the “fixed cylinder” is constantly being reloaded from the actual magazine. It’s not like it’s a fully automatic Webley-Fosbury.

  • 1leggeddog

    OK here is the tldr; for those who want to know how this works:

    The cylinder has 3 chambers, each with a bullet in it.

    When you press the trigger and the first round from one of the cylinder is shot and the gas activates a piston which drives and operating rod. Pretty similar design to what we know today huh?

    But here is the kicker:

    Instead of using the operating rod to do ONE full cycle of what we know today

    Shoot, open bolt, extract case, put in new bullet, close bolt

    This instead does:

    Round goes off. The gas pushes the operating rod to rotate the cylinder which has a cam path on the side of the cylinder. This aligns the next chamber with the barrel. The second round goes off. The operating rod is STILL going along its path, rotating the barrel from the gas pressure of the first round. The gas from the second round does NOT operate the rod. Again, the cylinder is rotated and the third round goes off.
    At this point, the spring in the operating rod pulls the rod back into its default foward position, ready to begin the cycle again. Oh and this also exposes the 3 chambers during the return of the op rod to eject the empty cases.

    • Max Popenker

      you describe rifle developed by GD
      This one was designed by GATX and had nine-round cylinder

  • Ben

    It seems that I’ve seen this before…and suprise it’s Russian, I speak of the ShKAS 7.62mm MG. My concern with this rifle as a prototype is the full auto burst controllable, or is this just anothe way to piss good ammo downrange?

    • SD3

      Exactly. This is why we can’t find 22lr, isn’t it?

    • Max Popenker

      ShKAS had a single chamber and drum was used only to trip rounds gradually from the belt. Entirely different beast.

  • The US Army Small Arms Systems Agency (USASASA) introduced the Dual Cycle Rifle (DCR) concept back in 1971. The brainchild of USASASA commander Colonel Raymond S. Isenson and Technical Director Leonard R. Ambrosini, the “dual cycle” referenced a burst being fired at a very high rate while feed and extraction occurred at a fraction of that speed. Testing of the SPIW had already shown how a conventional high cyclic rate mechanism with a single chamber and barrel could be unreliable. The SALVO-era multiple barrel designs suffered from excessive weight and bulk

    Fifteen companies eventually submitted proposals, and four of these were accepted for further study as paper designs. Two companies, General American Transportation Corporation (GATX) and General Electric (GE), were ultimately selected to develop firing prototypes. The winning proposals used a single barrel combined with a multiple chamber cylinder. The cylinder was fed from a box magazine holding three individual rows of cartridges. During the feed cycle, the top three rounds were simultaneously stripped
    into individual chambers. GE’s design used an asymmetrical three-chamber cylinder while GATX’s design used a symmetrical nine-chamber cylinder. By 1973, the prototypes reportedly achieved cyclic rates of ~4,500 rounds per minute in three-round bursts.

    The US Army’s basic design was US Patent #4,102,241:


    General Electric was US Patent #3,788,191:


    I have not been able to find a DCR patent directly credited to GATX.

    There is a small article on the DCR in the May-June 1973 issue of Army Research & Development Magazine:


    • FYI: The Small Arms of the World (Small Arms Review) website just uploaded a bunch of
      pictures related to the GATX prototype in their weekly archive update.

  • jimmarch

    Holy…this is a “second cousin” to Maurice:


    Kinda. And I seriously had no idea about it.

    Halfway through building it I found out about the late Nazi prototype 20mm autocannon called the Mauser MG 213:


    This rifle has features from that Mauser. It’s mechanically ramming three rounds at a time instead of one, and doing the burst-fire, but the feed cycle is basically similar. It also appears to be doing mechanical extraction.

    Maurice uses single-stage spring-loaded round injection, and direct gas powered extraction. And of course it’s still a single action revolver :).

    • Denver Garkie

      what about the not so theoretical ShKAS in 7.62x54r(150k units produced between 1933 to 1945) and the ShVAK in both 12.7×102 and 20x99r (with 20mm production of about 100k units between 1942 and 1946)

  • bbmg
  • Gabe

    Isn’t this a similar concept the the Dardick pistol? They developed a machine gun using .50 trounds that had an extremely high rate of fire. Of course the tround concept didn’t really take off.

  • Max Popenker

    It would be nice to see a link to original post with info on this gun, which is happen to be in my blog: http://mpopenker.livejournal.com/1716179.html
    also, the patent you link is for 3-chamber US Army / GD rifle; this one is GATX rifle (see commend from mr.Waters above), which has 9 chambers

    • Nicholas C

      Thanks Max. When I tried to translate your post, it was difficult to understand. A fault of Google Translate.

      • Max Popenker

        You always can ask me directly, it will be much easier.