RIA: Gyrojet Carbine

The Gyrojet was one of the more creative and one of the most futuristic firearms innovations of the last few decades – unfortunately it wasn’t able to prove sustainable on the market.

The idea was to use burning rocket fuel to launch projectiles, instead of pressurized gas. The advantage was that without the huge pressure of standard cartridges, a rocket-firing gun could be made far lighter and cheaper, as it had no need to contain pressure. The rockets would accelerate down the barrel as their fuel burned (and the 4 rocket jets would be angled to put a spin on the projectile for accuracy), and the weapon would actually have the most kinetic energy at something like 20 yards downrange, when the fuel was expended.

A decent number of Gyrojet handguns were made and sold (mostly as curiosities), but intrinsic accuracy problems prevented them from ever being taken seriously as weapons. The company behind the guns (MB Associates) went out of business shortly, unable to fully exploit their full range of ideas. One of those ideas was a carbine variant of the gun. A few hundred were made in two different models, and we have the chance today to take a look at one of the Mark 1 Model B sporter-style carbines.

48 Comments

  1. Although they were probably props, both the pistols and the carbines were featured prominently in a scene from “You Only Live Twice.”

    Interesting stuff as always Ian. Keep up the good work!

    • I wouldn’t bet on it; the Bond movies were worked on by Bapty, who would have had the real thing. It would actually have been easier at the time to buy real examples than to make props.

  2. I know it’s impractical and inaccurate but that doesn’t change the fact that it’s just cool! That screams James Bond clandestine work all over it.

    • It is probably a good thing that I don’t have a spare $2-3k. I would probably end up making the evening news with some sort of spectacular failure while trying to remake & use ammo for the thing. It’s just to awesome to leave sitting in a safe!

  3. Very interesting Ian, thanks so much for the presentation.
    I’ll as the question, for the guy that win’s RIAC’s offering, where to get and how much is the ammunition?
    Regards
    Pat

    • About $100 a round is what I keep seeing quoted, but it may be more nowadays. I have heard the ammo is much harder to find than the guns.

  4. Not the carbine but the Gyrojet-pistol saw some action in Vietnam, according to SOF:

    “Other suppressed pistols included Brownings, Walthers and Berettas, but SOG’s most revolutionary pistol—mistakenly acquired as “silent”—was the 13 mm Gyrojet Rocket Pistol. Constructed of plastic and stamped steel with the heft of a cap gun, the six-shot Gyrojet emitted a piercing, “whoosh!” when fired. Its thumb-size, solid-fuel rocket was spin-stabilized by two canted nozzles and generated almost no recoil. In SOG tests, that rocket punched through 3/4″ plywood and then pierced one side of a water-filled 55-gallon drum to dent the opposite side. Although slow to reload and of limited accuracy, the Gyrojet saw combat service, especially in the hands of 1st Lt. George K. Sisler, SOG’s first Medal of Honor recipient, who had one when he died fighting off an enemy platoon; his Gyrojet was recovered and may have been the same pistol Medal of Honor recipient Franklin Miller used later.”

    https://www.sofmag.com/behind-enemy-lines-weapons-of-vietnams-covert-warriors/

  5. When I was USAF aircrew during ’89-’96, Gyrojets were standard in survival kits for signalling. There were 5 (?) rounds and a small-Maglite-looking firing device that used a spring-loaded striker you’d release with your thumb. The Gyrojet would supposedly penetrate even jungle canopy.

  6. Ah, the ubiquitous GyroJet … one of my personal favorite weapons concepts! While this is the most public of this type weapon, due mostly to the James Bond movies, they were just a small segment of the research into RPP/RIP weapons including American, French, Polish and German projects. The major deterrent to development was the lack of understanding of rocket propulsion as demonstrated by later research. This is that at first launch the projectile/vehicle moves VERY slowly as is shown by early V-2/Atlas/etc launches. So at 25 yards the projectile was moving so slowly that the kinetic energy would not allow penetration equal to the task of a military weapon. But at range, they were devastating. The second problem, only recently proven was that they sued a multi-nozzle configuration harkening back to the Congreve designs in use during the American Revolutionary War. The ignition source was a common center-positioned primer surrounded by the drilled nozzles surrounding the primer pocket. This necessitated the use of machined cases. But the VERY tiny nozzles must be slant-drilled in order to impart the spin stabilization necessary for accuracy. This was almost beyond the capabilities of that time resulting in variations in angle of penetration of the drilled nozzle port, the diameter of the throat and in many cases, bound on microscopic examination of these mini-nozzles, to be partially clogged with unexpelled “swarf” particles that partially clogged the imperfect nozzles. This imparted an unstable thrust vector at the base of the projectile causing the rear of the projectile to pronate in an erratic fashion resulting in extreme variations on accuracy. However, in recent test, using electric etching technologies to “cut” the nozzles, this problem disappeared. As to an automatic version, the Germans designed, tested and perfected a variation of one of their Walther (if memory serves) SMGs that worked quite well but still suffered from the inaccuracies as described above and the production costs of the steel casings. But the concept is still under investigation and is closely linked to the research of the Base Bleed range Enhancement concept of Gerald Bull (HARP Project) and to the later developed RAP (Rocket Assisted Projectile) development that has given the old 155 mm field guns a maximum range of over 45 miles. The latest investigative project is to develop a long-range shoulder-fired weapon that cashes in on this and other technologies that are contemporary with the original RPP (Rocket Propelled Projectile) technology demonstrated in the GyroJet. The concepts are intriguing to say the least!

    • “suffered from the inaccuracies as described above”
      Generally (unguided) rocket propelled projectiles have less accuracy than projectiles without propulsion. For example http://world.guns.ru/grenade/usa/m1-recoilless-rifle-e.html states that: “Compared to contemporary M1 and M9 Bazooka anti-tank launchers, M18 recoilless rifle was noticeably more accurate(…)”.
      If I am not mistaken developing guided rockets lead to far more effective anti-tank weapons, so it could solve accuracy problem in hand-held weapon if small enough steering devices would available. I’m not expert at modern rocket system, so I ask whoever knows more: Is possible to build, say 20mm rocket with SACLOS system?

      “long-range shoulder-fired weapon”
      Sounds mysterious: what long-range is 5km? 50km? 500km? and how big payload for this system would?

      “old 155 mm field guns a maximum range of over 45 miles”
      Soviet 180mm cannon S-23 can fire both classic HE shell and rocket-propelled shell, range was respectively 30400m and 43800m, so as you can calculate, it give over +40% boost in range.

    • One minor correction. Congreve-type black-powder rockets were stabilized by a long stick (about 8X the length of the rocket body itself), and did not spin. They had the problem that if fired in a strong wind, they would almost automatically “weathercock” into it and go charging off upwind no matter which way they had been intended to go.

      The spin-stabilized rockets were developed by William Hale (no relation to the astronomer AFAIK) in the 1850s. The U.S. Army used Hale-type rockets exclusively from their introduction in spite of the difficulty of drilling out the angled exhaust effluxes, because they had less tendency to weathercock after firing.

      The Hale rockets were used in the American Civil War, and can be recognized by their single large central exhaust novel surrounded by three small angled ones that provided the rotary motion, as per the GyroJet small-arms rounds.

      The Congreve rockets originally had the guiding stick mounted on the side by brackets attached to bands going around the rocket body, and a large central exhaust efflux; later models had the stick mounted centrally with three or four straight exhaust ports around it. Which means that a “late” Congreve-type is hard to tell from a Hale if the guiding stick is missing.

      BTW, both the Congreve and Hale rockets were originally developed in England, based on concepts dating back to medieval China, where rockets were first used in warfare around the middle of the 12th century AD.

      Sources;

      Ley, Willy. Rockets, Missile, and Space Travel. NY; Viking, 1951, 1958. pp.67-81.

      Lord, Francis A. Civil War Collector’s Encyclopedia. (2 vols.) Edison, NJ: Blue & Grey Press, 1995 (orig. pub. 1963). Vol 1., pp. 218-220.

      von Braun, Wernher, w/ Frederick I. Ordway III. History of Rocketry & Space Travel. NY: Thomas Y. Crowell, 1966, 1969, 1975. (1975 ed. used.) pp. 30-34.

      cheers

      eon

  7. Sorry to over-speak/post, but I remembered something else was detrimental to the development of this concept in its original configuration: in case of a miss-fire there was no extraction cycle or any way of clearing a miss-fire without an overly long procedure. In case of a Partial fire scenario where the projectile launched down the barrel but failed to clear the muzzle, you were stuck with an obstructed barrel. This is not an advantage in combat. The German SMGs were prone to this and the weapon did not know it had an obstructed barrel so it sometimes sent another round causing severe problems. This is one of the problems later found with the so-called “caseless round” systems.

    • Alas, poor Gyrojet, I researched the potential successor, the Death Wind… And it still doesn’t fix the inherent quality-control problems.

  8. Many, many years ago (like back in high school, in the later Neolithic) I had a book on German experimental weapons, one of which was a shoulder fired multiple rocket launcher for use against low flying aircraft. The rockets were simply a 20mm projectile attached to a rocket motor. The launcher was a bundle of nine tubes. Essentially a panzerfaust for aircraft. According to this reference I Googled it was called a “Fliegerfaust”. It never went into production.

    https://books.google.com/books?id=8-ZmVU_iRcgC&pg=PA582&lpg=PA582&dq=German+WWII+20mm+rocket&source=bl&ots=Xi79nVzPan&sig=kbOd2RE6Rc0u4DLAHTVcYjulgP0&hl=en&sa=X&ved=0CFYQ6AEwC2oVChMIw-Og593JxwIVEEuICh2_dQrl#v=onepage&q=German%20WWII%2020mm%20rocket&f=false

  9. [Daweo asked: “long-range shoulder-fired weapon”
    Sounds mysterious: what long-range is 5km? 50km? 500km? and how big payload for this system would?] Approximately .32 cal rotation-stabilized Spire Point Rebated Boat-Tail Rocket Propelled Projectile (center nozzle). So far the muzzle velocity has consistently reached over 5,000 fps with a retained lethal velocity at over one mile. The “chamber pressure” is almost consistently flat from max pressure point to muzzle exit. Weight with full 20-round magazine is comparable to an M-14: Semi or Full Auto.

  10. I was able to do some shooting with this system as a youth. Yes, the terminal ballistics were quite impressive with no recoil and little report. But the accuracy was about minute-of barn.

  11. Ronald Regan owned a Gyrojet (pistol) and enjoyed shooting it at his ranch, he even wrote the company, when he ran low on projectiles, asking if they had any left.

  12. Hmm… I bet you could make this on a 3D printer, no metal, just have to work something out with the rocket, ceramic perhaps.

    • We have .950 caliber guns today. They are not NFA due to a sporting exemption. Gyrojet is an interesting tech and if the problems were solved it would be a fairly effective weapon especially if you had the tip of the round be explosive.

  13. “Generally (unguided) rocket propelled projectiles have less accuracy than projectiles without propulsion.” Generally speaking, this is true. However, reference the information found at http://gigconceptsinc.com/Rocket-Impulse-Prop.html and then couple this with a Paradox Profile barrel and a RPP projectile and you will see the difference. In fact, a Gyrojet with the Paradox Profile Barrel is more accurate at close range than a standard version with the smooth bore barrel but becomes less accurate at range due to the factors stated (pronation) previously. And as a point of reference, the Paradox Barrel was used in the large-bore muzzleloader era in Africa in 4-Bore to 2-Bore gauges to stop such large animals as elephant, rhino and Cape Horn Buffalo in their tracks. You can now buy some semi-custom Paradox barrels for such modern weapons as the Rem. 870and others making them a devastating dangerous game weapon. It is also now used in the more modern tank main guns. Therefore, a union of the most modern and more antiquated technologies is the latest thing.

    • A Paradox-rifled tank gun tube? Hmm. That could fire APDS “rod penetrator” rounds with minimal rotation (which wouldn’t degrade their accuracy), but still be able to fire conventional HE, HEAT, or HEP rounds with acceptable accuracy, which a “straight” smoothbore tube can’t really do unless the non-APDS rounds have folding fins like the old 106mm recoilless rifle’s HEAT round with the free-rotating sealing band had. Those folding fins were always a major PITA.

      cheers

      eon

    • I found some paradox choke tubes for slug use in shotguns also, maybe the Gyrojet could “metal storm it” so to speak I.e. Projectiles in the barrel, with each nose cone as a firing pin- Hammer hits the first, chain reaction. More chance of hitting a jet car thus…

  14. Way, way back in the late 70s, there was a report out of Cal. that Sonny Barger (Hells Angels International President) had killed a rival using a “jet pistol.” It was based on the testimony of an FBI informant, but was never proven in court. Sonny was also never charged with actually committing any murder himself.

    • The Volcanic was basically a hollow-based Minie’-type projectile that held its propellant charge in the hollow base of the bullet itself. The hollow base was sealed with a thin foil disc that had a priming pellet in the center. The hammer struck a firing pin which struck the pellet, firing the powder charge much like a standard percussion cap and launching the bullet downrange;

      http://www.mausercentral.com/mcgallery/data/media/5/VolcPis.jpg

      The system had originally been developed by Walter Hunt and Lewis Jennings a decade earlier;

      http://3.bp.blogspot.com/-ohzOA0qQRpU/VTs_QQvjBxI/AAAAAAAACu4/yi6Z0mFr-0o/s1600/rocket11.jpg

      Volcanic rounds were called “rocket balls” in their own day because they had no cartridge case or separate powder charge. Technically, they were an early form of caseless ammunition.

      cheers

      eon

        • The Jennings .54 cal. rifle of 1848 was the forerunner of them all, with a tube magazine under the barrel and a lever to operate the breech. It had a trigger “built-in” to the lever much like the (much) later Winchester Model 88 and Sako Finnwolf lever-action of the 1960s and early ’70s(!). The Jennings had a separate “pill lock” type primer system, similar to that of the Civil War era Sharps linen-cartridge single-shot breechloader.

          Originally, Jennings’ design and the Volcanic relied on loading up the bullet cavity with the priming compound and using it as the propellant, too, because it was easier to waterproof the priming compound than it was to even try it with black powder.

          But this had a couple of problems, namely that it made the ammunition very sensitive to being bumped, jostled, etc., even in the carton. Also, the priming (apparently a mixture of mercury fulminate and a picrate of lead or other heavy metal) generated so much pressure that it could literally blow the front half of the bullet off and out the muzzle, leaving a nasty lead ring stuck in the bore or even the chamber.

          The original French Delvigne’- Minie’ bullet with the iron “cup” in the bullet recess for expansion often did the same trick. Until they learned that it didn’t need the iron cup to expand and take the rifling, that is.

          Back in the late 1950s, Harold L. Peterson of the Smithsonian did some tests on a Volcanic rifle and pistol with newly made ammunition that duplicated the original patent specs as as nearly as possible. The .50 caliber rifle/carbine had a 180-grain bullet with a MV of 940 F/S, the .38 cal. pistol had a 130-grain bullet with a MV of 450 F/S. Neither one was up to the power of an equivalent rifle (like a .50 “plains rifle”) or revolver (like a Colt M1851 “Navy” .36) of the day, and neither one showed impressive accuracy (about 12″ at 100 yards was all the rifle wanted to do, and the pistol shot into about the same at 25 yards).

          Also, like the Colt Revolving Rifle, there was the danger of getting your face burnt with the rifle due to the lack of an effective breech-seal, and potentially even blowing the gun apart and your hand and/or head off with a gangfire in the magazine tube. The pistol was probably safer than the rifle in this respect, since it would be fired at arm’s length.

          12″ at 100 yards isn’t really much use in a rifle. But 12″ at 25 yards means that the pistol would probably be able to hit a man in the chest at that range. And power-wise, it fell in about the range of a Colt .31 pocket pistol, which would certainly kill if it hit something vital.

          Peterson concluded that of the two, the pistol was probably more generally useful, and I’m inclined to think he was correct. This may be why more Volcanic pistols were made and sold than the rifle version.

          BTW, late in their production lives, the Volcanics were made by the then-new partnership of Horace Smith and Daniel Baird Wesson, who had bought out the firm (and later sold its patents and assets to a consortium including Oliver F. Winchester). So some late Volcanics were sold marked “Smith & Wesson”, some of the earliest firearms to bear that name.

          cheers

          eon

          • Pdb;

            The Forsyth “scent-bottle” priming magazine had a filling port on the bottom with a rotating lid. The lid was designed to blow off if the priming reservoir ignited, to vent the blast in a safe direction.

            I suspect that Dominie Forsyth got the idea from Joseph Manton, the noted gunmaker of the time. He put platinum blowout plugs in the barrels of his pistols near the breech, facing out to the side. In event of an overload or other high-pressure event, the plug would blow out rather than the barrel bursting.

            It’s a simple safety measure, that for some reason modern makers of muzzle-loaders rarely (if ever) use. Granted, modern barrels of high-strength steel are much tougher than wrought-iron ones, but a little insurance never hurts.

            cheers

            eon

  15. FYI
    MBA kept limited production of ammunition and a small number of guns thru 1975 when a fire burned destroyed the production facilities. I was employed buy them from 1974 until they were bought out in 1979 or 80.Their main bread and butter products were Anti tank warheads,201g signal flares for air crews and IR flares for military aircraft.The gyro jets and 201g flares had a nasty habit of clogging a nozzle and doing a 180 degree turn and coming back at the person firing them. The Co. under different names is still producing IR flares.

  16. Eon: in the Congreve-type black-powder rockets vs Hale-type rockets post, I defer to your post. This is what comes with “older age” when your memory is about as long as your hair. For reference, if not for eye brows and ear hair, I would be COMPLETELY bald. But all this is indeed very intriguing. When you add in the Volcanic pistol/rifle predating the newer “caseless cartridge” concept, you begin to see that often old becomes new again. In ALL of the developments related to the posts I have made on this subject, you will see that most of the “innovations” I have cited are actually quite old if not ancient. For instance, I often hunt with a “caseless cartridge” weapon; a Thompson Center .45 cal Hawken with a Green Mountain custom order barrel with a 1:16 rifling. It does cede one point to “more modern” technology in that it has a small-rifle primer adapter instead of the older percussion cap nipple … but it is indeed “caseless.” On the Paradox Profile Barrels, the Germans experimented with them prior to WWII and were able to achieve a consistent 6,000+ fps muzzle velocity when using the perforated solid propellant grain described in one of my preceding posts in this venue. The Paradox Barreled tank weapon has an undisclosed muzzle velocity but it is greatly more than the older standard and often refereed to as “exceeding 4,000 fps” Couple this with a RPP attachment and you have tanks shooting an opponent at several miles range with devastating effect. Add in penetrator rods and you have a dead enemy tank and crew way before it is inside the effective range of the it’s weapon. And as a point of public information, the propellants used in the RPPs are almost exactly the same as used in the Space Shuttle’s Solid Rocket Booster. But he really hard development parameter that had to be overcome is the rotational and straight-line acceleration factors on the grain while it was in the combustion phase. The formulation is also almost exactly what we in the American Amateur Rocket Society use to great effect. I will close now so that I do not appear too addicted to this type of experimentation, if it is not already too late for brevity.

  17. If Gyrojet had asked me, I’d have built them a pre-engraved rocket with just enough bore engagement to spin the projectile as it went down the barrel (alllsame a rifled slug). Or maybe a muzzle section w/ enough rifling to spin the thing as it left the weapon? Oh I don’t know! They never consulted me and just look how they went bankrupt!

  18. What’s the reason for the holes on the sides of the barrel? They look to me like rocket exhaust pressure release. It seems to me that, if there were no holes, the projectile would develop a much higher velocity before exiting barrel. Thanks for the interesting video.

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