Ask Ian: Are Man-Portable Chain Guns Coming?

From Nikolas on Patreon:
“Have there been any attempts to make miniaturized man-portable chain guns? Do you think there’s a future for such a machine gun given modern advances in energy storage?”

Chain guns are a specific type of externally-powered machine gun. They have a single barrel, and used a loop of chain to control the movement of the breech and feed system of a machine gun so that it cycles under external power independent of energy taken from the firing cartridge. They are most commonly used in:

– 20mm-30mm cannons
– Armored vehicle turrets
– Helicopters
– Naval AA mounts

The benefit of a chain gun is its ability to cycle a dud cartridge right through the system without causing a stoppage. They are also unaffected by variations in powder charge, within reason. This makes them idea for aerial mounts. The ability to lock the action closed longer than typical machine gun designs allows them to leak minimal propellent gasses out the breech, an advantage for use in tanks and APCs.

For infantry-type use, these benefits are not particularly useful. They are offset by the increased weight required of a chain gun, both from the additional components to actually the bolt and also the electric motor and battery to power it. I can see development of this system for autonomous or drone-based applications, but not for human infantry.


  1. Lot of weight, not easy to move around, one round will kill you just as well as 300.
    And once that thing starts up, everyone around is going to know where it is a light that spot up. Not conducive to a long life.


  2. Aircraft guns traditionally solved the issue of re-cocking by adding a pneumatic piston and compressed air cylinder to perform this action. The chain gun is probably a simpler and lighter solution to this problem however.

    The Soviets/Russians developed a solution involving having small clearing cartridges which fired into the chamber to ignite a dud round. They fired a ball bearing to pierce the side of the cartridge case and then the flash would ignite the propellant. They had something like 3 or 4 of these clearing charges on a gun. It’s used on at least one model of aircraft gun in service.

    Other advantages of the chain gun is that the rate of fire and number of rounds in a burst (including single shot) are often programmable by controlling the speed and number of cycles of the electric motor. This is a feature which is very easily added to the system.

    Yet another advantage of the chain gun is that in aircraft use it can be readily cleared for safety purposes before landing at an airfield.

    Overall the chain gun appears to be a very clever design, but as Ian said the advantages are in specific applications and it’s not really suitable for infantry roles.

    If Ian can get his hands on a chain gun of any sort it would probably make for a very interesting episode because it has such an unusual action.

  3. I think the better “term of art” here isn’t “chain gun” but “externally powered machine gun”, as opposed to the general understanding of a “internally powered machine gun”.

    Why? Because, my friends, quoting from the Wikipedia: “As of 2019, “chain gun” is a registered trademark of Northrop Grumman Innovation Systems (formerly Orbital ATK, following several mergers and outright acquisitions after Hughes Helicopters) for “externally-powered machine guns”.”

    It’s like calling that stuff you blow your nose on a “Kleenex”, when it is actually a generic product from someone other than Kimberly-Clark.

    I actually wouldn’t be surprised a bit to hear that some trademark-enforcement lawyer dropped Ian a line in reference to this issue. Either they protect the mark, or they lose it, and they’re likely in danger of losing it due to the colloquial usages of everyone and their cousins in the military.

    As to the virtues/vices of the whole thing? It’s all a bit “horses for courses”. I could see using a man-portable externally powered machine gun in applications where you didn’t have good recoil resistance and/or you couldn’t count on being able to clear it. Consider the issues of trying to get a machinegun to work reliably on a mount like that Boston Dynamics dog-like robot; you’d be stuck with the fact that making it heavy and powerful enough to provide a stable braced platform for a recoil-operated MG would reduce its battery lifespan and a whole host of other issues. Replace that with something that’s externally powered, and all of a sudden, you’ve got other options.

    Gas-operated weapons also don’t do very well without steady recoil-resistant platforms. An external power solution might be very effective in these applications, so you never really know. I’d also submit that a chain-driven gun is also adding in a metric butt-ton of failure points because those chains wear and fail. You’d likely be a lot better off going to a direct-drive electric motor solution, now that we’re getting better at building the small brushless electric motors.

    Future days, the whole thing is probably going to be very interesting, because of all the different considerations. Imagine trying to build a small arms system meant to be usable in zero gravity, for example… One you’d have to compensate for the recoil effect such that you wouldn’t be blasting the shooter off on an equal and opposite ballistic trajectory. Do that, and you’re probably looking at something a lot like a micro-dose version of a Carl Gustav, fired either over the shoulder or under it. That mechanism is almost going to have to be externally powered, just by nature of the “recoilless” feature.

    • “(…)small arms system meant to be usable in zero gravity, for example… One you’d have to compensate for the recoil effect such that you wouldn’t be blasting the shooter off on an equal and opposite ballistic trajectory(…)”
      Sounds like task which can be done by GYROJET.

      If you are interested in weapons for low-gravity environment then see images

      “(…)almost going to have to be externally powered, just by nature of the “recoilless” feature.(…)”
      There existed automatic recoilless rifle namely MK 115

    • The main problem with any “externally-powered” machine gun is…power. Where does it come from?

      On an aircraft, no problem. As long as you have an engine on you can run a generator off it. In an emergency, a ram air turbine (RAT) will do in certain circumstances. Although if you’re down to RAT power as on an F-4 Phantom, using your Vulcan cannon is probably not high on your “To Do Right This Instant” list.

      Ground vehicle mount? Again, as long as the engine is running, you’re good to go. Engine off, you need an auxiliary generator or serious batteries. (This BTW is another strike against the latest pipe-dream of electric-powered AFVs and etc.)

      Man-portable? The best comment on that was the original Predator (1987). Blaine’s (Jesse Ventura) M134 Minigun (7.62 NATO, not an XM214 5.56 as often stated) may have been “man-portable” to a pair of weightlifters like him or Bill Duke, but the power source to run it was a large bank of 24-volt truck batteries off-camera, with the power cables hidden in the grass or etc.

      The “Predator” gun also points up the other major drawback of such weapons in “manpack” mode; who carries the ammunition? Every man in a WW2 Wehrmacht infantry section carried belts for the MG34 and/or MG42; the latter at 1,200 R/M could go through eight or nine 250-round belts in a few minutes even in properly-applied short bursts.

      An M134 Minigun fires either 6,000 R/M full rate or 3,200 R/M low rate. An L94 (British version of the 7.62 Northrop-Grumman Chain Gun) fires 520 R/M, so it’s in the same range as most conventional 7.62 NATO LMGs. The U.S. EX34 version (originally intended as the coax on the Bradley/Devers) fired 500-600 R/M. Meaning, about as fast as the old M1919 .30 Browning coax of most of our WW2 tanks.

      Either one is reasonable on a vehicle mount. As a man-portable weapon, neither one is as usable as a standard LMG.

      Your choice is a heavy, externally-powered weapon that has an appetite for ammunition your infantry section can’t hump, or a heavy, externally-powered weapon that is really no more effective than an M240G.

      And besides the ammunition, somebody has to hump the batteries, too.

      Either way, externally-powered man-portable machine guns do not make very much sense on an actual battlefield.

      The TANSTAAFL rule applies to weapon design, too.



      • “Either way, externally-powered man-portable machine guns do not make very much sense on an actual battlefield.”

        Exactly; a consideration of “chain gun” for infantry use sounds like “academical”. It does not make any practical sense. I advice anyone in doubts: look what is in use in Ukraine.

        • “(…)advice anyone in doubts: look what is in use in Ukraine.”
          Please take in account, that regarding “grounded” aviation weapons, it is more likely that they will be post-soviet ones. For example I would not be surprised if someone would use GShG akin to 1st photo from bottom here
          Observe that whilst GShG has rotating cluster of barrels akin to M134, it is self-propelled (does not require external source of energy).

  4. A bit off topic but …
    A semi-automatic is defined as one round fired for each pull of the trigger. Could a chain gun be “programmed” to fire buy the number of trigger pulls? Could this then make the chain gun “semi-automatic”

    • I believe this is something already covered by particular regulations here in the US. If you made a programmable gun that had fire modes reliant on that programming, than the ability to make it fully automatic with nothing more than the push of a button or a program change makes it a machine gun regardless of the mode it’s in.

    • That could be possible, but why bother doing that? An externally powered rapid-fire gun isn’t designed for pin-point single shot accuracy. In the majority of installations requiring a chain gun, the usual objective is “obliterate whatever the gun’s got in its sights, preferably before the target gets within fisticuffs range.” I could be wrong.

    • “(…)Could this then make the chain gun “semi-automatic””
      Depend on how precise electric motor is, observe that if you would get reliably one shot at one time you would need stepping and appropriate gear ratio. If said electric motor does not have such feature it might be simply not precise enough.

    • Looking at the article, I’d say the weight of the gun alone would be the same or slightly heavier. You’d need a bipod, stock, and trigger system, but you could remove some other bits that are tank specific. But the battery would be heavy. There’s also the issue of battery life. May want to carry spare batteries with you if you are going to be in the field for more than a day or two.

  5. The first think I thought was a ground drone with a chain gun on it. When it runs out of ammo, it can announce “I’ll Be BAAAACk”.

  6. Ten minutes into the video, Ian starts explaining the many reasons why a man-portable, externally powered machine gun is quite improbable.
    In particular the dud/overloaded/underloaded cartridge used in favour of an externally powered man-portable machine gun is in my view not very realistic. Ok, I experienced duds -I mean real duds, not a jam caused by an untrained operator- but they are so rare and easily cleared in a man portable weapon, they cannot seriously be used as a pro-external power argument.
    While Ian mentions the problem of additional weight due to a battery, the dominating feeling during my military service was: when you need a battery, you will find it is dead. This applies to reloadable as well as non-reloadable types in my experience.
    In a conventional machine gun, as long as you have ammo, you have firepower.

  7. My Vax onepwr “hoover” battery just conked out incidentally, PRC made; warranty etc… Don’t fancy calling customer services in the middle of a battle; modern manufacturing, you buy something and it has “insurance” for spare parts or you buy spare parts, what do they call it on Google Play (Contains after purchase, purchases or such.) Future war, an Amazon driver turns up in the middle of say a “WW1 Somme” type battle wearing airpods oblivious to there surroundings, with your replacement battery reads the delivery note and throws it into the opponents trench while you recieve an automated email stating you were not at home so it was left with a neighbour. 800yrds away, behind some barbed wire as it turns out.

    In the Brit Warrior AFV you can swing the Huges chain down, think it is upside down on a hinge to change the barrel; but yes you can imagine it getting smoky in there for sure really.

    All I can say is that “really” is really well worth avoiding, as it would really; be really shit all round.

    I liked the chain gun; I emailed a head honcho of Mc Donnel Douglas about it off a pound every 5 mins early public access internet computer in a pub. He replied incidentally which was nice, talked briefly about… What, I suppose you could now describe as drones i.e. Wee pilotless helicopters.

    Funny isn’t it the internet that was 2002 or so, now I am on a phone; on the internet.

    Maybe a “Hybrid” recoil, charges the battery; he he. Mind you electric cars eh… Still think like a 19th electric vehicle I.e. A tram, is like more “Green” if we are doing it to like stop posioning the planet and annoying Greta etc but meh, personal opinion.

    • The “bullet” penetrator things off those 30mm guns do (pin ball) you know, if they get through the armour; it just pings everywhere inside the turrent until it runs out of steam. With you being inside the turret, and consisting of… Fairly mushy stuff; and it having a lot of “steam” you can imagine how you would probably be turned into a (milkshake) in the event of this sort of stupidity actually taking place.

      • I don’t drive “You’ll be glad to hear, with drinking…” Which is less rare in Europe, than in the U.S… America being bigger I.e. More distance to cover, than in England but I must say I very much doubt electric cars a green. In comparison to a tram… Know what I mean? I have know problem with the combustion engine; bar there are to many cars, and thus likekly fat folk due to it. But I just find it hard to imagine that the exact same number of electric cars as oppose cars will really be of benefit. I mean, come on… It just looks like it should have BOLLOCKS in a big cattle branding type font, on it.

    • Actually my “nuclear fart” barrell could expand by gas, and compress the piezo thingis… Or the niti, could be a stronger compression spring… As oppose a spring. Meh, might as well share it with you guys; end up in a spam folder these days he he.

      True story that, emailing the vice president of mc donell douglas from a pound computer; guess spam folders had not been invented he he.

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