Hudson .30 Cal Machine Gun Toolroom Model (Video)

Robert F Hudson developed a series of machine guns for the US Navy during the 1920s and 1930s, including this .30 caliber example as well as .50 caliber and 1.1 inch versions. What makes these guns unusual is both the attempted use of a counter-balanced system to eliminate felt recoil and also the standard use of suppressors on the guns. I don’t know much else about the guns, but you can find the documentation mentioned in the video here:


    • I don’t think that it works with magazines. Generally this kind of implement requires a belt. If there’s no stock, the machine gun will generally not be magazine-fed unless you count the Hotchkiss heavy weapons. Did I mess up?

      • Hopper is another possibility. Since mounted MG stays in more-less steady position (ignoring elevation/ depression), it may be useful approach how to feed it.

  1. I tend to look at every firearm as a “fixture” (basically a piece of tooling) because what it does: it facilitates discharge of bullets. Shape, form and detail features are not necessarily how I evaluate given design. Functionality and practicality I see as the valid criteria.

    But, having said that, I am thoroughly intrigued by this gun. Just the stated fact, it deals with felt recoil is very exciting. As I usually do not dig deep, I trust other people will uncover some more information and post it. Thank you!

    • “uncover”
      See Савин Норов machine gun (or to use official name «7,62-мм скорострельный авиационный пулемет обр. 1937 г. системы Савина — Норова»):
      see 1st drawing from top, this weapon is mixture of various solutions:
      Bullet is fired, when it is past gas-port, piston (2) is moved forward and thus whole barrel goes forward (as in blow-forward) it is linked via wheel-of-gear (5) and thus linked element (3) goes backward.
      Cartridge feed is similar to ShKAS machine gun.
      This solution was to allow high rate-of-fire (2800-3000 rpm, but this vary on source), this gun was used (attached to I-16 Type 19) during Talvisota, but with poor reliability results.

      I suspect that such solution allowed smaller travel of point-of-center-of-mass during firing and thus give less stress to mount. I also found locating spring around barrel poor idea, as it can fail after heating.

    • You are correct, a gun is simply a tool for launching a projectile(s). Soft recoil is a bonus but usually comes at the expense of increased complexity. I see a slow but long term trend to use existing components and tweak them for lighter felt recoil, i.e. inline stocks, lower bore axis, less abrupt changes from recoil to counter recoil. If you look at the lockwork of a Rhino revolver, recoil management comes at a price.

      • “Soft recoil is a bonus but usually comes at the expense of increased complexity”
        For example Boys AT rifle
        has barrel which might move to soften recoil. It has also muzzle brake (Canadian made version has different muzzle brake) to lower recoil, but anyway it proved to be complicated and has harsh recoil.
        Generally muzzle brake are simple (no moving parts) for recoil reduction, on the other hand might give effect of cloud of dirt, especially with AT rifles.

        • True, muzzle brakes are simple and soften recoil, but it is an extra part. The Boys AT Had the heavy action slide back in a chassis which was like hitting your shoulder with a hammer and punching you in the cheek. If the spring stopped the action, instead of slowing it down, it might have been a better design.

      • Right, increased complexity….true.

        At the same time let’s consider that what drives the mechanism (as funny as it sounds) is for large degree the source of the problem. Dealing with is in secondary way (aka recent AJ line) in not necessarily nor productive way how to do it. Yes, it quells vibrations from mass oscillation but that’s about all.

  2. The “balanced action” is actually one of the areas of development where we would actually see some significant changes in modern/future firearm design.

    The AK-107, AK-108, and AK-109 (derived from the AEK-971) use this system. (5.45, 5.56, and 7.62 respectively.)

    I also think of the video that ian and Karl did with Jim Sullivan where they demonstrate Sullivan’s virtually recoil-free AR variant. See the video at: and go to around 10 minutes in (actually watch the whole interview.)

    The Arms West system demonstrated is presumably *much* less complex than the balanced-action designs and it would be great to see a detailed comparison.

      • And there was also СА-006 by Константинова and Кокшаров
        You might be not aware of Константинов if you are not interested in mid-20th-century fire-arms of Soviet Union. None of his design go into mass-production, but he was serious competitor to other fire-arms designer and thus was motivation for other to improve their weapons.

        • Константинов and his weapons:

          Photos from top to bottom:
          -Александр Константинов
          -5,45mm small-size Константинов avtomat АЕК-958. Experimental model. Stock unfolded
          -same as example, but with stock folded
          -5,45mm Константинов avtomat СA-006, experimental model.
          -7,62mm Константинов sniper self-loading rifle. Experimental model of 1959
          -7,62mm Константинов machine gun 2Б-П-40. Experimental model of 1956
          -7,62mm Константинов avtomat 2Б-A-40 with bayonet
          -7,62mm Константинов machine gun 2Б-П-30. Experimental model of 1957

          • Daweo, thank you very for posting the link with such a comprehensive text on A. Konstantinov creations by Sergei Monetchikov (I have his book on the history of the Soviet Avtomat btw), which I will read with interest.

          • I’d like to know if any of the many experimental/prototype military weapons from the Soviet era ever got smuggled into America. Larry Vickers has done a whole series featuring many of them, but he had to visit Russia to film it.

        • Yes, it was developed concurrently with that cartridge.
          It was decided in 1966 to develop new system (5,45-mm cartridge, avtomat and machine gun). First trials were in 1968 (this event is known конкурс 1968 года)
          Many designers take part in this competition but finally AK-74 win. There were also other “balanced” weapons:
          АО-35 by Шилин
          АЛ-4 by Александров and Нестеров
          АГ-021 by Дерягин and Ткачев
          ТКБ-072 by Коробов (similarly to Константинов, he was competitor in many competitions but win none), which has also other peculiarity – 2 available RateOfFire – HIGH giving 2000rpm and NORMAL giving 500rpm
          and there was one classic weapon Kalashnikov which later will become AK-74

          but finally only Константинов and Kalashnikov designs were considered worth further development, Константинов proved to be more accurate, but Kalashnikov design was well-known for industry:

  3. Does anyone have a scanned copy of U.S. Navy Ordnance Pamphlet No. 806

    Title: 1.10-inch machine gun, 75 caliber, Mark 1 and mechanism Mark 1

    This is the 1.1″/75 gun that according to Wikipedia was “based on patents of Richmond, Virginia, inventor Robert Hudson”

    It would be interesting to see if this is one of these “balanced” machine guns.

    • Yes, Hudson’s 1.1″ machine-gun was the basis for the U.S. Navy’s quadruple 1.1″ water-cooled “Chicago Piano”, an overweight, complex and generally unreliable shipboard AA mount with a very low rate of fire that was, fortunately, mostly replaced by 20mm Oerlikon and 40mm Bofors mounts in different configurations as the war progressed.

      • Earl Liew,

        That’s interesting to hear. From video that I’ve found online of the gun functioning it appears to have a recoiling barrel inside its water jacket. That seems different from how the Hudson mechanism works.

        Do you have a reference that shows the internal mechanism? I’ve not been able to find anything about it.

  4. Sort of reminds me of the God-Awful Japanese mentalaliity that thought short mag co-ax in their tanks was a good idea. Or for that matter any of their WWII tanks at all.
    Or for that continuing matter, naked, unarmored, on-decks storage of pure oxygen charged torpedos on cruisers. Really otherwise good technology is almost always squandered by poor, irresponsible, or otherwise stupid application.
    Look up “The Battle Off Samar” and see exactly how a slow and pathetic American “Jeep” carrier, armed only with a single rear facing 5″ gun sank a Japanese cruiser (the Chokai) with a single (VERY) lucky shot.
    Sometimes all you need to be is lucky.
    It would make Billy Dixon proud.

    • RE: Luck

      By contrast, nobody wanted to get anywhere near USS William D. Porter. “Don’t shoot! We’re Republicans!!” And IJN Yukikaze was unflatteringly nicknamed the “Grim Reaper” because most of the ships she escorted got sunk with all hands, though none of her own crew suffered more than a stubbed toe!

      For your information, Japanese torpedo tubes were not unarmored trays sitting around in broad daylight waiting to get blown to bits by rifle fire (if you’re some sort of videogame hero). The best protected Japanese ship-mounted torpedo launchers I’ve seen in photographs were actually HEAVILY ARMORED TURRETS capable of resisting Browning M2 and even Bofors projectiles. The true danger of pure oxygen sitting in the torpedoes was detonation due to concussion, not due to getting sparked-a-la-Hindenburg-myth.

      As for the magazine fed machine guns in Japanese tanks, there was not even enough room for an ammunition belt! And besides, Japanese capital ships took priority on the material budget! Given that the main line of machine guns in the Japanese Army’s arsenal was based on the French Hotchkiss heavy machine gun (fed by strips or magazines), should you be surprised that there was no belt feed for a tank machine gun?

      • I’ve been on PT boats several US Submarines, at least one U-boat, and enough vintage & modern Destroyers to constitute a flotilla. (No vintage Japanese cruisers though. There seems to be a distinct shortage of those, for some reason.) In other words, most of the devices used to launch torpedoes. I’ve never seen anything remotely describable as a “heavily armored turret.”
        Generally one wants to minimize weight and mass in the superstructure as eventually there will be too many turrets and armor and such and serious stability issues. This (theoretical) battle cruiser wouldn’t be the first to capsize from too much weight mounted too high.
        The other issue is simply, it’s a bad idea to store a high-explosive warhead in close proximity with charged flasks of pure oxygen INSIDE your own hull. With you.
        Better it be outside your armor AND unconfined, should something go “blooey.”
        Environment is really not an issue. Remember, they’re torpedoes. They’re waterproof. They’re so rugged they can shoot a hole right through the side of a freighter, get stuck there and not even go off. Even when they are supposed to. (See ‘US submarine torpedo failures, WWII”) :):):)
        I suppose you could go down to the wreck of the Chokai and check it out. Bring your swimsuit as it’s 8100 meters down :):):)
        As to the tank mg thing…there you are in your early war tank-lite or tankette or tank-like-device faced with, oh, say an enemy battle cruiser. Before you cut loose with your co-ax, would you rather have a 30 round magazine on tap, or a 3000 round belt…?
        Or better still, a slightly bigger tank with a 3000 roun belt):):)

        • Try the torpedo tubes on Kagero class destroyer Yukikaze. I’m pretty sure her tubes had an armored superstructure.

          • Sorry CD, you’re being fooled by the application of apparent weather sheltering, probably canvas sheeting to protect refugees or trade goods. The photo you are looking at was taken likely in 1946 post WWII after the armament was removed (including the rather conventional torpedo launchers.
            Look up “RCOS Tan Yang” AKA “formerly IJN Yukikasi”. A rather sad story but by then she was not even classified a warship but rather a Transport.
            Nobody needed defeated Destroyers anymore nor torpedo launchers that had no torpedos to fit.

          • According to the official description of the Kagero class destroyers, those torpedo tubes were housed in ARMORED SUPERSTRUCTURES, not canvas. And the photograph I referenced (sadly I didn’t source it) was taken in 1939, NOT 1946. Try a photograph of IJN Tanikaze, a ship of the same class. According to the Wikimedia entry, this was taken on March 31, 1941. The torpedo tubes are NOT covered in canvas, as canvas CANNOT support steel access hatches and lots of rivets on the side!!!

            Check here, and you will see that the torpedo launchers were sheltered by armor plating.

    • “Japanese mentalaliity that thought short mag co-ax in their tanks was a good idea. Or for that matter any of their WWII tanks at all.”
      Italian tanks of that era also have machine gun with quite short magazines, for example Breda 38:
      has magazine for 24 rounds, Fiat M13/40 has twin machine gun in hull probably to counter this drawback.

  5.”Hudson+Robert+F” This appears to be the patent. He has two others patents/US1386872 and patents/US1749137

    A few minutes reading the first few claim no mention of a balance is claimed. The bolt move against a spring and the gas system drives the block that seems to prevent the next bullet from entering the barrel. It will take a lot more time to figure out what actually happens.

    • Thomas Sutrina,

      I’m wading my way through the related patents, the first one that mentions recoil reduction is:

      “With the foregoing and other objects in view, the invention resides in a novel arrangement of machine gun in which the gases of explosion are used merely as a setting means while spring-actuated means are employed as the real operating mechanism for the gun, thus providing in a gun of this type a stationary barrel gun with the least possible recoil and one in which the rapidity of fire may be regulated as, for instance, from a single shot per minute up to one thousand shots per minute.”

  6. Here is a list of the related patents, I’ll let you copy and paste into your favorite patent search engine:

    US1386872 – Robert F. Hudson
    –Application filed March 20, 1919
    –Renewed January 3, 1921
    –Patented August 9, 1921
    This is probably the first “Hudson Gun” mentioned in the oldest business documents above. Its novelty is to gang the guns together 180 degrees out of phase, allowing the combination to “self clear” misfired shells. I’m going to guess that this resulted in the gun exploding eventually. ^__^

    US1749137 – Robert F. Hudson
    –Application filed February 28, 1923
    –Renewed February 28, 1927
    –Patented March 4, 1930
    –Assigned to Automatic Guns, Inc.
    This patent does not claim any recoil reduction. In fact it includes the design for a recoil absorbing mount.

    US1786207 – Robert F. Hudson
    –Application filed December 12, 1927
    –Patented December 23, 1930
    –Assigned to Automatic Guns, Inc.
    This is the first patent that claims recoil reduction as a novel feature of the design.

    US2112660 – Robert F. Hudson
    –Application filed June 26, 1929
    –Patented March 29, 1938
    Note that this patent is not assigned to Automatic Guns, Inc. This patent reads more like a text book rather than a patent. Also note that this design has dispensed with the rotating barrel cam / clutch mechanism. I’m going to guess that this locking mechanism is the one that’s used in the prototype in the video. Also note that the “suppressor” is actually a muzzle brake.

    US2135005 – R.W. Hoagland et al
    –Application filed June 20, 1936
    –Patented November 1, 1938
    –Assigned to Automatic Guns, Inc.
    This is a refinement to the firing mechanism carried out by Automatic Guns, Inc. without the inventor’s input. This activity may be what is referred to in the business documents.

    US2192677 – R.W. Hoagland et al
    –Application filed June 20, 1936
    –Patented March 5, 1940
    –Assigned to Automatic Guns, Inc.
    This patent is for a positive round feeding mechanism for the 1.1 inch version of the gun. Note the trigger shape, much like what is seen on the prototype in the video.

    Enjoy! ^__^

  7. Questions: ZB30/Besa? Gas gun with recoiling barrel and body, timed to fire succeeding shots during each return from recoil? Not the same concept?

    • LDC,

      The Besa’s gas piston travels rearward, just like any conventional gas operated gun, where this Hudson design’s gas piston travels forward.

  8. US2112660 Starting in claim 10 the patent mentions that the gas driven piston moves forward to balance the recoil. You can see in the figures the locking feature in the receiver moving forward. So the gas driven piston has to be in front of the gas port at the end of the barrel. and a seal is needed behind the gas port. The seal lets the piston rod extend back to the receiver and the components within. I can not picture the reloading of bullets into the barrel. A slide plate is used to detect the presents of a cartridge that was not ejected. How the cartridge is ejected I have not seen in the figures. Maybe the first patent covers some of these features better.

    • Thomas Sutrina,

      The gas port can be seen in Figure 3a at #53 and Figure 4a also at #53.

      An ejecting case can be seen in Figure 4 at C”
      A cartridge ready to be fed in can be seen in Figure 4 at C’

      Does that help?

  9. Brian Thank you. I just scanned the patent again. Takes a long time to understand a patent. items 22 and 23 are the extractor but Fig 4 does not seem to have them in a position to work. More reading needed.

    Page 2 of the patent talks about the relationship of the weight and speed of components to get a balance. More reading needed.

    Finally the gas port in most guns are near the end of the barrel The gas port in his first patent is close to the casing and the second that we saw a shop product for is farther down the barrel but not close to the end. Fouling to me seems to be a potential problem. But then again I am just a simple minded mechanical engineer. So what does an expert in forgotten gun tell us from all those gun testing reports. Is fouling a likely problem?

    • Thomas,

      Sometimes patents are deliberately vague on the exact details of a design so they don’t completely give away how something works. All I can tell you is that patent US1786207 seems to have a similar extractor and ejector scheme. For more exact details you’d have to examine an existing example.

      As to reliability, who knows, you’d have to build one, tune it up until it works, and run a reliability test. Just be sure to do it on video and post it on YouTube so we can all take a look! ^__^

  10. In Volume 4 of _The Machine Gun_ by George M. Chinn many of the features of the Hudson machine gun are used as examples in “Part XI – Schematic Illustrations of Representative Mechanisms”:
    Figure 6-64. Operating Rod Cams Locking Block Free of Receiver – page 358
    Figure 6-108. Rotating Drum Unlocks Bolt. – page 404 (this is from the earlier Hudson patents)
    Figure 12-3. (A) Methods of Retaining and Operating Ejectors. – page 457
    Figure 13-10. Sear Operated by Locking Block. – page 472
    Figure 17-1. (A) Types of Muzzle Brakes and Flash Hiders. – page 495

  11. Also with the help of George Chinn’s excellent set of books I found the following patent:

    Filed in 1887 and published in 1889, this has the gas port near the chamber, the piston that blows forward against spring pressure, and the bolt pushed to the rear by that spring in front of the piston.

    No telling if any of these would have held up in court against the even earlier Maxim gas operated patents that used a gas chamber in front of the muzzle to power the mechanism like the Bang Rifle.

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