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Gauss Gun Theory

Last week SayUncle, in the daily Gun Porn, pointed to this fully automatic gauss gun. I have looked into the possibility of building such a device, but I’m troubled by the implications of some of the theory. At least if I’m understanding it correctly. From that, it would seem that a gauss gun that uses conventional non-superconducting electromagnets can never really perform as well as even compressed air, at least no without having impractically huge coils. I don’t know as much about this field (no pun intended) as I should, so if anyone who remembers electromagnetism wants to opine, I’m all ears.

28 Responses to “Gauss Gun Theory”

  1. The Noob says:

    Depending on how the magnets are made up and how much power they have going through them, it could get some pretty nasty power behind it.

    It’s a give and take, however. More coils makes stronger magnets but add weight. Stronger capacitors can pump more power through but it takes longer to power up. I’ve seen video of single shot gauss guns that can punch through ballistic gel like a normal pistol.

    The average gauss gun that can be built by the average nerd, I personally see taking the same role as the “Liberator” pistol. It’s not meant to be the end all defense weapon. It’s more of a path to obtaining a better gun.

    Either way, with the recent advancements in rail guns as well as the creativity that geeks are showing with gauss guns, it seems some of the sci-fi weapons that nerds like me have dreamed about for years are finally becoming reality.

    Now if they could only figure out the flying car.

  2. DevsAdvocate says:

    Are Gauss Rifles regulated similarly to other firearms and airguns?

    • Sebastian says:

      No. They aren’t firearms under the federal definition of firearms. Even New Jersey’s broad definition of firearm doesn’t include a gauss gun, though it would include air guns.

      • Ian Argent says:

        I’m sure a judge would bend the law to cover; though. It covers spring guns. At any rate, even if it wasn’t a firearm, it’d be a “weapon,” and you don’t get to possess one of those without a “readily explainable lawful purpose.”

  3. NotClauswitz says:

    I think I’d rather have a “Gauss doorway” that worked on pure energy instead of transferring it to a kinetic mechanism – kind of like an electronic portcullis. The stack in the door would remain stacked, and then if one touching the other: zap-zap-zap…acting like an electric fence?
    Or is it not that kind of energy weapon? I was a Liberal Arts major so Science is all Scientesterrific to me…

  4. Andy B. says:

    Without spending a lot of time trying to remember old parameters I once knew but have forgotten, it pretty much comes down to a question of how much energy you can store in your storage media (batteries or capacitors) and then how quickly and efficiently you can access it to convert into kinetic energy of your projectile.

    Back in SDI (Star Wars) days I subcontracted to build a 100,000g shock generating machine for the DoD. I.e., we needed to accelerate several pounds of carriage and test specimen to 100,000+gs for a duration of several milliseconds. We used some relatively huge electrolytic capacitors and a pancake coil, because capacitors can dump their energy very quickly.

    We succeeded, and we could crank the levels up high enough to tear apart carriages made of 1/2″ T7075 aluminum. We were concentrating on accelerations, so I forget w, which hat velocities we imparted to those several-pound objects, but it took a lot of backstop to catch them.

    After spending the better part of $1 million on the project, the government lost interest and never bothered to come around to collect either the machine or our reports. My associate who had been the prime contractor eventually cannibalized the system for its capacitors, which he tried to use in the development of everything from electric landmines to electric airbags for cars. But in nay case, to some extent we did demonstrate the feasibility of using electrical energy to produce high kinetic energy with some sizable projectiles.

    • Andy says:

      Hm. Did the acceleration have to be sudden? I’ve always wondered if, with a slower ramp time to not destroy the projectile and a suitable length, such a launcher would be suitable for LEO satellites.

      • Jeremiah says:

        Concepts like railguns and coilguns have been suggested for LEO insertion. Coilguns don’t have the energy density, if I recall, and railguns have a flaw- if you slow down you end up welding the rails vice riding them. There is always a catch…

  5. Sam P says:

    Magnetic field strength inside an ideal solenoid is 4*pi*10^-7 * coil turns/meter * current. Notice how small the constant is. So you want high turn density and high current, but these are opposing requirements as high turn density means fine wires which are bad for high current, i.e. the wires tend to melt unless the wire insulation is really poor in which case you get arcing between coils through the insulator.

    While poking around, I found this: title=”Barry’s Coilgun Design site”>Barry’s Coilgun design site. His last completed coilgun was able to accelerate a 0.4 gram 1.25″ T-head nail to 18 meters/s…

  6. aerodawg says:

    I’ve always thought railguns had a lot more potential as a viable weapon than gauss guns. Just off the top of my head they lend themselves to a simpler mechanism and greater efficiencies.

    I honestly don’t think it’s pure chance that’s the direction the Navy has gone with their research…

  7. wizardpc says:

    I’ve always thought railguns had a lot more potential as a viable weapon than gauss guns

    I always thought those terms were interchangeable.

    • Sam P says:

      A Gaussgun/coilgun is a series of solenoids (coils) which generate a magnetic field inside the coils, which is used to accelerate a projectile (through the center of the coils). A railgun uses two conducting rails and a moving conductor (“armature”, which may be the projectile or a holder for the projectile) connecting the rails; pass a current through the rails and armature and a force is applied to the armature which accelerates it down the rails.

    • Ian Argent says:

      Railguns require a different kind of unobtanium – unlike coilguns, the projectile and the “barrel” are in contact. At the speeds involved, even Teflon isn’t cutting it to reduce the friction. This is apparently considered an engineering problem by the Navy, though.

  8. Keegan says:

    While it is a very neat concept, most cool guns can only achieve the kinetic energy of a BB gun.

  9. Jeremiah says:

    Coilguns have limitations in the physics and timing circuits. Add in the inductance of the coils and power requirements and this ends up being a bit more like a science experiment more than an actual weapon. Railguns can pack more energy in a smaller package without the timing requirements, but with other issues. I would like to see a pancake coil and railgun combination (load and accelerate respectively). But there isn’t enough time in the day to do all the cool stuff…

  10. Pete S. says:

    http://www.youtube.com/watch?v=mdZo_keUoEs seems relevant, though somewhat snarky. :)

    (The guy has a series of humorous engineering-related videos in which he gives himself minor injuries.)

  11. Bill Twist says:

    Seems to me this gun would work better if they person put some fins on the projectiles to keep them flying straight. They obviously possess some kinetic energy, but in watching the video there is a major problem with keyholing due to lack of rifling or fin stabilization.

    Now, it may well be that a sharp-nosed projectile like that doesn’t need as much kinetic energy as a blunt-nosed bullet to penetrate sufficiently, and that the lower energies available from something like this aren’t as much of a handicap as it might first appear: After all, millions of deer are killed by archery equipment every year, and even the zippiest compound bow has less kinetic energy available than a .22 LR.

  12. Brad says:

    For small arms forget gauss guns, or even rail guns. Hybrid electro-thermal guns are the way to go.

    I imagine something like an electric-ignition cartridge with the ignition element pulling double duty as an energy dumper into the working fluid of the burning gases of the cartridge. Of course any practical benefit over conventional ammunition still requires advanced battery technology.

    • Ian Argent says:

      Electric-ignition ammunition would be useful in a SHTF/reloading scenario if the initiator can be reused. You don’t need primers…

      • Bill Twist says:

        Until, of course, your batteries run down.

        If you really, really, *REALLY* think things are going permanently south, get a flintlock. You can knap the flints yourself, and if the lock breaks or you can’t get flints, you can always use it as an improvised matchlock.

        • Ian Argent says:

          Electric Ignition shouldn’t take a lot of power – worst comes to worst, you could rig a hand crank. I’d make sure the final stage is a capacitor, not a battery. Those should be a good deal more long-lived. (A really smart monkey would try and do it with piezoelectricity, but I suspect that’s A Simple Matter of Engineering ™.)

          • Bill Twist says:

            Electronics break. A tube with a small hole at the back is much, much less likely to break.

            BTW, there have been modern muzzleloaders with electronic ignition: http://www.fieldandstream.com/pages/electrifying-muzzleloaders-cvas-new-electronic-ignition-system

            They haven’t really caught on, nor have electric primers for centerfire cartridges. I believe Remington messed around with those a while back.

            • Ian Argent says:

              Agreed on electronics break; but realistically, I’d rather have a crossbow than a flintlock at that point. Making my own powder would be a pain in the #$%$, but a crossbow using all the modern engineering refinements would be just about as useful overall as a muzzle-loading flintlock, less vulnerable to weather, faster to reload, etc.

              • Bill Twist says:

                Actually, a more primitive crossbow would be better. Easier to fix if something goes wrong. If you have a “wheelie bow” based crossbow, you’ve got a lot more parts that can possibly go south on you. One based upon a simple wooden stock with a simple (but powerful) bow and using the classic rotating nut/tiller style trigger is really hard to beat from the standpoint of both simplicity and reliability. Track record of over a thousand years.

                Also, learn how to knap flint for arrowheads. It’s easy to do, you can practice on beer bottle bottoms, and pretty much any non-tempered glass or ceramic, natural or man-made, can be knapped into a decent point. I’ve knapped heads out of bottles, flint, obsidian, plate glass, broken power line insulators, and even a Pfaltzgraff plate my wife dropped and broke.

              • Bill Twist says:

                BTW, crossbows really aren’t any faster to reload. I can reload my flintlock in about 20 seconds or so. Once you get the ‘muscle memory’, you can do it pretty fast. If mine was a smoothbore, I could probably shave a couple seconds off that time.

                Also, flintlocks aren’t that vulnerable to the weather if you load them right. You run a bead of patch lube (generally animal fat and beeswax) down the barrel/stock channel about 6 inches in front of the lock, and you run a bead of it around the pan, and on the frizzen where it meets the barrel. That seals up the entire system.

                Plus, one of the major accessories to have for a flintlock is a piece of wax or oil impregnated leather that covers the lock in inclement weather. It’s called a ‘cows knee’.

                I’ve gone hunting with mine in a constant drizzle, starting in the morning, and it will consistently go off if you do what I’ve outlined.

                Flintlocks tend to get a bit of a bad reputation for reliability because most people who try them don’t understand how to manage them, and in some cases they get frustrated because the skills needed to keep them firing are different than modern guns, or even percussion guns. But they can be very reliable if you know the little tips and tricks.

        • Jeremiah says:

          I understand where you are going, but this is unrealistic. If things go south in just the US, there are many other countries willing to make and sell modern firearms and weapon systems(Russia is the prime example). You won’t need a musket, just something to trade for an AK (pick your variety). My guess of what you need if no one can produce a firearm is probably a simple spear- a nuclear war has happened and the likelihood you would find many people in the first place is pretty remote. In both cases, muskets probably won’t come into the picture.

          In any case, all of the technology from bows to modern weapons is worthless if you don’t know how to repair or manufacture them and their expendables (arrows, bullets, gunpowder etc). Otherwise it would work for a while, but it won’t take much for your powder to become ineffective, you run out of balls, a spring fails or some other simple failure which renders the weapon useless. This, by the way, is why the gun control bills recently attempted, and passed in some situations, have no method to pass some weapons to someone else. Eventually it will fail, and the state will win. Ask the Nepal rebel fighters how muskets work against modern weapons… if you can find any of them alive.

  13. Jim Bullock says:

    I can’t help remembering something attributed to Henry Ford. Paraphrasing:

    “The first example of a new technology is always inferior to a developed example of an inferior technology.”

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