Room for innovation: Could man-portable Chain Guns become a reality?

Hughes EX-34

Hughes EX-34

When dealing with conventional automatic or semiautomatic man portable firearms, a failure to fire usually results in one having to manually clear the misfired round and chamber a new one.  What if there were a firearm that would automatically eject the misfired round and chamber a new round with another pull of the trigger (or in full auto by just keeping the trigger depressed), with enhanced reliability and higher mean rounds between failure than conventional firearms?  What if this same firearm also vented almost all gases forward for suppressed use in a semiautomatic or automatic format?  What if this same firearm also offered a programmable/variable rate of fire, a shorter receiver length than conventional arms, and is capable of forward ejection for ambidextrous use?  The technology exists.  Chain guns (the term “Chain Gun” is a registered trademark of Orbital ATK)  offer this capability.

M242 Bushmaster

M242 Bushmaster

What is a “Chain Gun”?

Chain guns, often confused with rotary-barreled guns such as the “minigun”, are single barreled guns operated by a linked chain.  This chain is attached to a “master link” that runs in a rectangular pattern on the receiver.  The chain drives a rotary bolt back and forth to complete the firing cycle, rather than relying on gas or recoil energy to cycle the firearm.  This allows the bolt to stay forward until up to 96% of propellant gases vent down the barrel before the next firing cycle.  The chain itself is powered by an electric motor that relies on an external power source.

Detail of a chain gun's action.  Image source: worldguns.ru

Detail of a chain gun’s action. Image source: worldguns.ru

Notable chain guns in service are, among others:

  • 30mm Mk44 (Used in the MC-130 Dragon Spear)
  • 25mm M242 Bushmaster (M2 Bradley IFV)
  • 30mm M230 (AH-64)
  • Hughes EX-34/ H&K L94A1/ 7.62mm Bushmaster Chain Gun (Warrior IFV)

The latter iteration leads me to believe that further miniaturization and portability is possible.  The 7.62mm Bushmaster weighs only 30.2lbs/13.7kg, or only 4.4 more pounds than an M240B, and boasts a MRBF of 50,000 rounds.  In one test, two 10,000 round bursts were fired with no malfunctions.   Reliability is not an issue with chain guns.

M230, the Apache's main gun

M230, the Apache’s main gun

Possible portability

If these guns were modified to feed from a magazine, there could be a reduction in complexity, weight, width, height and power needed.  A shorter, thinner barrel for semiautomatic use would reduce weight as well.  Power supply would not be the biggest issue, as technology continues to get smaller and lighter in that arena.  The current model requires 26.5 volts of direct current, which can certainly be provided by a battery.  If a tracking point type sight mounted to the gun were slaved to a helmet-mounted display, such a weapon system would truly be the stuff of science fiction.  It’s easy to see, however, how developments in the defense industry are imitating art in that respect.  Configurations of chain gun rifles and/or pistols in many calibers could be possible.  What do you think, readers?  Will we live to see and utilize man-portable chain guns in our time?  Would such an operating system be useful for military, defensive, or sporting purposes?  This author believes so.

ATK's improved 7.62mm Bushmaster Chain Gun with barrel shroud

ATK’s improved 7.62mm Bushmaster Chain Gun with barrel shroud.  Ththough it has multiple fins around the muzzle, this is a single barrel gun, as to avoid any confusion with a “minigun” or gatling gun



Rusty S.

Having always had a passion for firearms, Rusty S. has had experience in gunsmithing, firearms retail, hunting, competitive shooting, range construction, as an IDPA certified range safety officer and a certified instructor. He has received military, law enforcement, and private training in the use of firearms. He is fortunate enough to have access to class 3 weaponry as well.


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  • Julio

    Chain guns make sense when you have (1) the capacity to carry lots of ammo and (2) effectively inexhaustible power on tap, which is why they’re found in AFVs and combat aircraft. However light the gun may be, man-packing the ammo and batteries required to keep it effective as a weapon imposes limitations which leave other systems looking like better choices. As a novelty on a range -where electricity and ammo are readily accessible within feet/yards firing point-, a chain gun might pay its way, but I can’t see any other utility for one out of a military context.

    • Herp

      Do any of these designs capture wasted energy from the gun to charge the battery though? I wonder if the gun could power a small generator so you’d need less battery.

      • whskee

        None do that I’m aware of. The 25mm puts out 10,000lbs of recoil energy, 7k of which are absorbed in a recoil dampener and the final 3k by use of a large muzzle break. It would be very complicated to harvest the recoil usefully without some large addition. They don’t suck a lot of juice unless they are in operation or powering director optics like in the Navy MK 38 Mod 2.

    • Oronzo

      we could solve the ammo problem, but not the ammo carry issue.
      A chain gun would only make sense in .22 LR then….

  • Uncle Festet

    To cycle the action, we can used manual energy (bolt action, etc), bleed some energy from the shot (gas, recoil, etc), or use external energy (motor).

    Because batteries (including spares) are inherently heavy, I can’t see a man portable version working any time soon EXCEPT possibly a vehicle mounted version that could be dismounted for defending fixed positions.

    Taking one out in patrol? Nope.

    • George

      A 1-lb LiPo battery pack should run the Ex34 at 600 rounds per minute for ~10 minutes. It only needs 0.3 HP / 0.22 kW of power.

      What that means for individual weapons would need scaling, but if it’s multiple thousands of rounds per lb of battery power is not the problem…

      • Uncle Festet

        What if you are in a 15 minute firefight? What if you run out of spare batteries?

        I also left off the weight of the engine.

        Basically, a man portable Chain a Gun would suffer from a significant weight penalty for very little reliability gain.

        For vehicles( which could keep the batteries charged automatically), they might be a great solution,

        • jamezb

          I think the point is, If battery packs weigh just a pound, carrying multiple packs shouldn’t be an issue. Combining this technology and, say lightweight plastic cased ammo, OR , using a robot “mule” (existing technology) as a ammo /battery carrier would greatly extend the amount of portable, sustainable, firepower a small squad could bring to bear.

          • Uncle Festet

            Roughly speaking, a 1 lb battery means giving up a 30 round magazine. If I am carrying it, I would rather have an extra mag vs an extra battery.

            Even if I have a robot “mule” mule to carry things, I would rather have more ammo /firepower than batteries.

          • George

            The battery to fire 600 x 10 rounds (6000) weighs one pound. The ammo in belts weighs 210 pounds.

            If you believe that the battery is the problem you are focused entirely on the wrong end of the elephant.

          • Vindice

            No ammo is being given up. Period. With ten minutes run time, literally dozens of batteries would be needed for anything but the smallest patrol. I’m humping a ruck on a 72 hour mission carrying a big heavy support weapon, I really don’t want a second ruck just for batteries. The infantry already carry a ton of batteries, most people’s goals are to reduce the power requirements, not increase them because its “only a pound” for every ten minutes of use.

          • George

            That’s ten minutes (6000 rou ds) of continuous firing. 210 or so lbs ammo.

          • William Elliott

            why not use multiple smaller batteries, and put them in the base of the magazine? That way when you swap the mag, you swap the battery, empty or not. You could also have the magazine be a conveyor system instead of sprung affair, actuated off the cycling of the arm. Removes the bulk of the spring, increases potential capacity…
            So many variations…I just want my M41A 10mm caseless pulse rifle…

          • Paladin

            That’s not 10 minutes of being in a firefight, that’s 10 minutes of continuously holding the trigger down at 600RPM, or enough power to fire 6000 rounds in a single 1lb battery. Find me a soldier who can carry 6000 rounds into combat, and we’ll give him a second battery.

          • Vindice

            Hats right, but the gun is going to be powered up a lot more than that. It may not be drawing it’s full charge, but it will be draining it whenever it’s outside the wire. The weapon will probably be carrying some kind of optics on it as well, which may very well require their own batteries, although ideally they would just be wired into the main battery. There’s also the risk of additional systems “needing” to be attached to it, as with the C-16, to “maximize” it’s potential. In my experience with chain guns they are not nearly as reliable as this article implies, will provide no weight savings, and will add an additional logistics burden of some sort of battery, likely something different than anything else uses, because that would make sense. I’m still not seeing where any benefit comes in that justifies additional batteries or more complexity, or really any reason to change other than the sake of change.

          • Paladin

            There’s no reason for the gun itself to draw any power whatsoever unless it’s firing. As for optics, an aimpoint can run for 5 years on a single CR2032 battery. Even if it was powered off of the same battery as the chain gun, the draw would be insignificant. As for a Tracking point type optic, that’s going to require the same amount of battery power regardless of whether it’s mounted on a chain gun or a conventional firearm, as far as the discussion of the merits of a man portable chain gun, optic battery draw is neither here nor there.

            There are reasons not to adopt a man portable chain gun, but battery power is not one of them.

  • Ajax Scout SV

    An Exosuit/Power Armor would fix the weight and power issues. Though the current concepts look like something you see in Fallout.

    • BattleshipGrey

    • Justin Roney

      Yep, my thought exactly.

    • PK

      Yes, it’s all coming together so deliciously, isn’t it? Give it another decade or three.

  • BattleshipGrey

    I’m not privileged enough to be able to play with these types of firearms, so I never really thought about the operation of a chain gun and didn’t really know they weren’t a minigun, though I think DOOM is the only place I’ve heard a minigun called a chain gun. I found this pic helpful.

    • mechamaster

      Yes, it’s a bit ‘technical blunder’ there, the DOOM Chaingun is not a real chaingun.

  • mechamaster

    Caseless Ammo, or Cased Telescopic Ammo ( 7,62 or 6,5 mm ) in the man-portable chaingun…
    And deployed like the GPMG Machine gun 2-man team..
    Plus the capability to do the Quick-Change Barrel…
    Well, fun concept to imagine, really…

    It’s like the miniaturized, man portable scale 40mm CTAI CTC.

  • Randomer

    Just to point out that the Chaingun as mounted in Warrior and Challenger has a terrible reputation for jamming at the worst possible moment. It has caused Infantry units duric Telic (Iraq) to in the past carry Minimi in the turret for the commander to use as a close in weapon due to the high likelihood of a stoppage.

    Now a lot of this is due to the installation (on Warrior the whole weapon is essentially upside down so the feedpath if working against gravity not with it as originally intended) but it is not a popular weapon.

    Waiting to see what reports come out about it from Ajax (where apparently the installation is much more sensible).

    • Rusty S.

      I believe there were also unintentional discharges due to the way they wired the gun to the firing controls in the warrior.

    • jamezb

      Saying that the idea won’t work because an example doesn’t work fails to take in consideration that we are talking about an as yet to be designed theoretical man-carried chain gun, not an existing, possibly flawed chain gun model.. By that reasoning, An M240 must not be feasible because the Chauchat was an unreliable design.

  • Joe

    Volts mean nothing. I can give you 26.5 Volts in the size of a pen or less. Watts means everything. Driving a chain belt like that may or may not be difficult for a lightweight battery depending on how many watts it draws.

    Also, even if you could drop the weight of the gun down to sub 20 pounds…how much ammo can you really carry to feed this beast?

    • George

      My reply with the ATK datasheet got held in moderation queue, but…

      220 watts. Literally toy / model airplane power needs.

    • jamezb

      A Craftsman Cordless drill is a good analog for one of these guns. If you haven’t used a cordless drill lately, you might do well to experiment with one, You can drive 3″ drywall screws into 4″x4″‘s and chances are excellent your wrist will give out before the battery needs a 2 second quick-change. Cycling an action should require less torque than forcing a drywall screw into wood. It’s a fine tuned machine without the bolt spring resistance of a conventional firearm, you’re turning clockwork, not flipping a brick.
      As I said above, by eliminating the cycling problems currently associated with it, polymer cased ammo becomes practical, and the option of using a robotic walking mule as an ammo carrier is a real-world-existing solution, no longer a sci-fi dream.

  • George

    Electric powered guns have a future.

    That said, issues with Chain Guns in particular:

    As with Gatling Guns they have spinup/spindown and are not well tolerant of pausing for each semi auto shot on user control. Better suited for fully automatic.

    More moving parts to achieve forwards/back linear motion than say a solenoid, which is easier to pause for semi auto fire / cycling.

    More moving parts period.

    • iksnilol

      I’ve never seen spinup delay on real miniguns. It’s just a movie and game trope.

      • George

        I have. But I’m dealing with milliseconds and microseconds, motor start/stop electrical and mechanical profile, inductance and reactance in the circuitry, part acceleration and jerk and jounce.

        Worst issue is that Chain guns pause anywhere mid-cycle, no big deal. For an autocannon. Not as safe with half-loaded round in semi-auto.

        Really, linear bolt carrier motion and a solenoid in/out power stroke is a lot simpler electrically and mechanically and matches the idea of electrification of existing proven actions very well.

  • Bierstadt54

    Sounds like katie 2.0. And no, this is not a good idea. Adding weight and complexity and external power dependence is a massive negative for a personal firearm. On a vehicle, not so much. Which is why chain guns are used where they are used.

  • ixlr8r

    Why only consider an electric option? There are many ways to store the energy required. Including a spring, stored gas, a manual handle, or stored hydraulic pressure. Store enough energy to clear 5 rounds, and charge it with every successful discharge.

  • Austin

    I thought the chain rifles fell out of favor by the 1870s…

  • Richard

    I immediately thought of the mg42 thingy from aliens

  • LCON

    sounds like something for the Next War Machine Armor in Iron Man 4. I just don’t think these can be conventional infantry weapons, but perfect for armored vehicles or even better on UGV’s where the system could be a major boone as even if enemy infantry managed to disable it and try and salvage the weapons off it they would be unable to use them.

  • so what I’m hearing you saying is that you want our Colonial Marines to have these on a Steadycam mount for faster dispatching of Exomorphs.

    I am hearing that right now.

    …By which I mean DARPA MAKE THIS HAPPEN ALREADY.

  • Roy G Bunting

    Seems like a lot of cost in weight, complexity, cost and additional requirements. for a potential increase in reliability.

    If we want to add battery powered accessories to firearms, how about gyroscopic stabilization for DMR and long range rifles? There was an ancient magazine I read where they experimented with a gyroscope and were able to make off-hand hits at extreme range. IIRC the best place for the gyroscope was between the buttplate and grip. This is something that has actual increased capabilities for the average shooter, combatant and the competitor and doesn’t disable the firearm when the battery dies. It could be integrated into aftermarket buttstocks.

    • Tassiebush

      yeah i think that could have been rifleshooter mag. it was definitely a cool concept.

  • Some Rabbit

    There is always a trend toward miniaturization. However, the strength of a chain is based on the size of it’s links. Thus, a small chain is a weak chain, prone to breakage. And gas or recoil operated guns are self powered, requiring no batteries. So I see impediments to the concept. But what the heck, let’s build a prototype and see.

  • Squirreltakular

    Bringing up MRBF is interesting, because most malfunctions in traditional issued rifles are a) caused by the magazine and b) easy to clear. The weight could be minimized down the line, but the extra complexity and need for an external power source means that we will probably never see these as man portable versions until Iron Man/Fallout/Elemental/Mjolnir armor exists.

  • derfelcadarn

    Even with significant lightening of the weapon and an esoteric power supply system the heft and bulk of the vast amounts of ammo remain an obstacle to portability

  • spotr

    I think it is inevitable. The definition of “man-portable” is going to change n the near future.
    Lockheed Martin HULC (Human Universal Load Carrier)

    • iksnilol

      That’s what our power armor is gonna look like?

      Man, I am disappointed. Lockheed Martin better get some artists and aestethic designers on board. I don’t want a bulkier version of ACUs, I want a T-51b or PNB-4UZ.

      • UCSPanther

        I would love to see some power armor that looks like something the Marines from Starcraft wear…

      • noob

        HULC is just an exoskeleton – a forklift attached to your legs, and in no way is HULC armour – there is no protective benefit whatsoever.

        Now you could possibly put plate armour that looked like anything you wanted over the top and use the HULC to carry the extra weight.

        I’m imagining the burden of having to maintain all these moving parts in the field.

        Imaging waiting in line at the 3d printer for a new knee servo?

        Or having the chain of your personal weapon on the floor in an oil pan as you try find the loose link and replace it with your chain breaker?

        Zen and the Art of Chain Gun Maintenance.

        • iksnilol

          3d printing a servo doesn’t seem that safe.

          • noob

            better to be 3d printing a new knee servo from metal powder, than to be faced with having an inventory of 600 left hip servos and 0 right knee servos for your company and resupply is not for five more days. you could end up cannibalizing half your force over the next week for parts.

      • DW

        X-01 is the real deal yo

      • LCON

        No, I am sorry but the Fall out exosuits are not Practical you may as well want Ironman Armor. It’s to big to bulky that’s not what infantry exosuits will look like. Infantry Exosuits are a Evolution more then Revolution, taking the basics of existing infantry kit and adding a system to reduce the load. Revision Kinetic operations suit it my bet. It’s not just the lower body Exoskeleton but A load chassis that extends up to take the load of the plate carrier and a system to take the load of a combat helmet with all the Accessories. it also has leg armor.
        make it in Multicam,and replace visor with a polycarbonate visor like those on Revision’s battleskin probably based on their Viper helmet.
        and as to the MG for infantry my bet would be add to it a Tyr Tactical Mico and a KAC LMG or a reduced weight M240 on a steadicam arm.

      • Tassiebush
  • Tassiebush

    I want a rimfire version that is hand cranked including a gyro-scopic flywheel to smooth out the action and stabilize it. I have no legitimate reason for it but it really would be fun! trigger could be a clutch that engages flywheel to the chaingun action. the gun would have a front pistol grip with the trigger and the rear grip could move back and forwards to crank it the action.

    • noob

      now that is genius – the trigger is the crank, so you are legal as far as it being a machine gun.

      unless the trigger is the clutch. better call a lawyer.

      • Tassiebush

        Hmmm how about we call the clutch control a grip safety.

  • Chi Wai Shum

    If I remember correctly, the 7.62mm chain was used on the a few British AFV but they are not as reliable as we would assume. Thus there seems to be no intention to use them again in future British projects.

    • NukeItFromOrbit

      As far as I know this is primarily because on the Warrior IFV they mounted it upside-down so it often has problems with the feeding system.

  • RealitiCzech

    That would be a useful gun for fixed positions (like the Korean DMZ, and bases with plentiful electrical power). For man-portable, you have the tremendous weight of ammo as well as batteries. I would only recommend such a weapon if your schedule is insufficiently flexible to permit exsanguination.
    I’d prefer the .338 MMG. It appeals to me to have a MG that has equal/superior range to most sniper rifles, in a package much less gigantic than the M2.

  • guest

    Short answer: no.

    Long answer: Occam’s Razor is a fine way to analyse something, it is also a way of engineering in a manner of speaking. If say a machine gun works well as-is, which in nearly all modern SAWs or otherwise portable machine guns is gas piston and rotating bolt, then having it driven by external power brings nothing to the table. Having chain guns as opposed to truly automatic guns is an american way of creating a solution for a problem that did not exist. That is the first point.
    So much so that until “chain guns” appeared post-ww2, they filled a “gap” that did no exist as all machine guns and automatic cannons were either blowback, short recoil or gas operated. So though the dubious “reliability” of chain guns is an excuse when for some reason the ammo and/or gun malfunctions, unlike chain guns external power was ONLY (no exception!) needed to manually cycle/unjam the gun. I am deliberately omitting electrically fired guns, as they used – and still use – an electrical impulse instead of a mechanical actuator, which has nothing to do with cycling the gun. Or put in other words the trigger and charging handle are not the same thing, though the end result is almost the same.
    Let me re-phrase that then: if up until chain guns came around external power was needed only to un-jam the gun, and there was always some manual backup in case a powered remote cycling failed, chain guns need power ALL THE TIME and will NOT operate otherwise which means that the gun and the power source are a package. With any other type of automatic weapon – not so.

    So of course if by modern standards inherently unreliable guns like the ones that use direct impingement for infantry have become “too simple”, then of course say… an electromagnetic coil can yank the carrier back and fourth instead of the powder gases. The upside will be no disturbance of the barrel, which is a non-issue really, the downside will be that the soldier will have to find a USB-adapter in the field or whatever that can be used to plug in his battery pack and charge it up, because just inserting a new mag is sooooooo pre-2020. Or something.

  • aka_mythos

    I think a man portable revolver cannon like the 25mm and 20mm cannons on some aircraft would be easier to manage in making into a man portable weapon. This type of weapon design allows a piston driven gas system that takes the linear motion of a piston moving down a track running around the outside of a revolver cylinder to drive the rotation of a revolver cylinder with a simple cam to trips the hammer. Such a system has fewer parts albeit more involved from a manufacturing stand point while the general design is more easily tuned to a particular rate of fire that can exceed a chaingun. Unlike the chaingun it doesn’t require a motor to drive it either.

    • George

      Two issues:

      One, revolver cannon (or generally, guns) as with revolver pistols has a cylinder-barrel gap and leakage, which is more significant at higher pressures.

      Two, the traditional multichamber revolver cannon setup has the complexity on clearing and checking clear of the additional chambers which are largely obscured rather than openly visible in revolver pistols. Somewhat of an issue for civilians… And ranges.

      One chamber revolver cannon have been done in some form but it’s not clear that it makes sense then. The LSAT light machinegun rotating chamber is technically similar but really is reciprocating rather than spinning completely…

      • aka_mythos

        I don’t see why a man portable revolver cannon/rifle couldn’t break open like a revolver handgun… It’d be similar to how an AR opens when only the rear takedown pin has been pulled. In this case the seam between mating halves of the recievers or a dust cover would just have to be located such that when open you could look into the cylinder that would remain attached to the now drooping barrel assembly.

        As far as bore gap goes there have been a number of ways it’s been effectively eliminated or mitigated. One would be to enclose the front end of the cylinder such that when fired the discharge from the gap is simply redirected. The other method is one in which the opening of each chamber of the cylinder has machined a profile that mates to the breach of the barrel; where by the whole cylinder is pushed forward to close the gap when firing and only disengages after the barrel pressure drops to a safe level. In this way the front of the cylinder is acting like bolt face in a delayed blow back system. While it becomes a relatively large mass that’s reciprocating it only travels tenths of a inch.

  • iksnilol

    To be honest, what I’d like to make is a bore evacuator on an automatic rifle. Should help with gas blowback when firing suppressed.

  • gunsandrockets

    Aside from the more obvious issues of lightweight high volume of fire firearms, there is another factor critical to an infantry weapon, ammunition quality. Externally powered guns need greater ammunition quality compared to self-powered guns.

    One of the reasons the Maxim gun was such an advance over the Gatling gun was because of the problem of squib rounds and catastrophic failure modes with the Gatling.

  • john4637

    Can you imagine one per fire team!

  • Jokuvaan

    As manportable no. A guy carrying a 7.8 kg PKM can carry about 5.9 kg more bullets than a guy carrying a 7.62mm Bushmaster weighing 13.7kg.
    That would be about one loaded 100 rounds belt with the box and another 100 rounds spare in paper boxes.

  • guest

    NO. Because chain guns are heavy. Because they’re electrically powered and driven by a linked chain, hence the name, and whatever increases in reliability are present are offset by added weight and the requirement for power, making them suitable solely for use in vehicles.

    And consider that the FN MAG/M240 has been demonstrated in service to have a mean rounds between failures figure in excess of 25,000 rounds.

    Now ask yourself what you’re really buying by hauling around that fifty-pound “GPMG” and the hundred and fifty pounds of car batteries to run it.

    Next question?

    Oh, those “fins” at the muzzle? It’s called a “flash suppressor.” You’re welcome.

  • Gorilla Biscuit

    Well if this guy can do it with a Gatling???? Why not a chaingun??

  • n0truscotsman

    Why?

    Are current belt-fed, gas operated medium machine guns so controversially unreliable? no they are not, unless you still have M60s in service.

    And increased reliability? thats very questionable, given the history of previously serving chain guns which have a rather questionable reputation (like the L94A1, which, is cited as being extremely reliable, although, from personal sources I consider far more reputable, it is far less cut and dry).

    They’re best for serving as vehicle mounted weapons. not infantry portable ones.

  • letter@to-the-ed.com

    Like I said, Ed: the quality of posts on this website is declining precipitously.

    Who was the genius who thought More Crappy posts would make for a better site than Fewer Good ones?

    • George

      Why would you say that? The action and components series and design issues not to your liking?

  • Joe

    OK, at 16.5 volts that’s 13 amps. An example of a widely used portable rechargeable military battery is the bb2590. It has 225 watt hours (low rate capacity, reduced at high rate) and a nominal 14-15v so it’s close to the required voltage and may work. Downside is you’ll need 2 in parallel as the max it can do is 10A.

    So you’ll get 1-2 hours of shooting for 6.2 pounds. That’s a third of your gun weight.

  • David Harmon

    Anyone that has ever operated on a Bradley can tell you that those things do jam, and they are a nightmare to clear when they do.

  • Rocketman

    Give me an old fashioned Klingon Disruptor any day.