Science, Fiction, Life

What is a Gauss Rifle?

A couple weeks ago I took a look at railguns, how they work, and how the ones depicted in Starcraft 2 don’t look much like the real thing. This week I’d like to look at another favorite exotic gun in sci-fi video games: the gauss rifle. In Starcraft, the marines carry gauss rifles that act much like real-world assault rifles. In other games, like Fallout 3 and the Mechwarrior series, gauss rifles are a sniper weapon, used to do lots of damage at a distance with a single shot. So, what is a gauss rifle, really? And is it anything like those depicted in the games?

A gauss rifle (also known as a gauss gun or a coil gun) is actually much simpler than the railguns that I talked about before, but it also is based on electromagnetic forces. In a gauss gun, the barrel is a solenoid: essentially a big coil of wire. If you send a current through a coil of wire, it creates a magnetic field in the middle of the coil. We can use the right hand rule to prove this to ourselves: just point your thumb in the direction of the flowing current, and your fingers will curl in the direction of the magnetic field. Make your thumb follow an imaginary coil and you’ll notice your fingers always point the same way!

Animation of a basic coilgun. Source: Wikipedia

In a gauss rifle, this magnetic field is used to accelerate a magnetic projectile, essentially pulling it along the barrel of the gun. If you were to leave the current on, you’d just get the bullet stuck in the magnetic field, oscillating back and forth, but by carefully timing the current so that it turns off at the right time, the projectile will go flying out the end of the gun. In some cases, several coils in a row are used to accelerate the bullet to very high speeds.

The advantage of a gauss gun is that it is pretty simple, and doesn’t really have many moving parts. The difficulty is in getting the coils to turn on and off at just the right time, and in pumping enough current through the wires to accelerate the projectile without destroying the coils with the heat generated by their electrical resistance. If you’re dealing with a sci-fi setting, you can say that the coils are high temperature superconductors, which gets you around that particular problem.

I don’t know of any actual military uses of rail guns, but there are hobbyists who make them, and based on the videos I’ve found on YouTube, they are at least strong enough to blast holes in various household objects.
[youtube=http://www.youtube.com/watch?v=GjMTffRav-I&w=480&h=385]

As you can see in the video, these aren’t exactly machine guns. It takes a while for the capacitors to store up enough energy to fire the gun, so I don’t know if a gauss rifle would ever work like a machine gun, as they are depicted in Starcraft. I think the sniper rifle role, as seen in Fallout and Mechwarrior is probably more plausible, though I’m not sure there would be any advantage over traditional guns.

My biggest problem with the gauss rifles shown in Starcraft is not the rate of fire. It’s the shell casings. In every cinematic, we see marines blasting away with their guns, casings flying all over the place. Heck, in one of the videos in Starcraft 2, we see a closeup of the casings piling up on the ground as the terrans try to hold off advancing zerg forces. It’s a nice cinematic touch, but why would a gauss rifle have casings? Those are there to hold the gunpowder behind the bullet! If you don’t have any gunpowder, there’s really no need for a casing, is there? I think this is another case where the “cool factor” was most important. The guns carried by marines are called gauss rifles because it sounds cool, not because they’re actually based on real gauss rifles.

The marines in Starcraft sure use a lot of bullet casings considering their gauss rifles don't use gunpowder.

32 Comments

  1. Kevin

    http://www.metalstorm.com They use this principle and multiple barrels in parallel to create guns with absurdly high firing rates.

    • Nick

      Possible, but taking ten seconds to charge a capacitor bank would mean ten barrels and ten separate capacitor banks to fire at the rate of only one bullet per second. This is not even to consider the size of the battery pack needed to last more than a few minutes.

  2. MiriV

    http://sclegacy.com/editorials/34-general/653-quantifying-the-c-14-impaler-gauss-rifle

    a nice writeup on the SC gauss rifle.

  3. Ichinosei

    My estimation on the casing is maybe the casings do carry gunpowder to launch the bullet, but the coils of electricity magnify the round to make the weapon able to pierce an object with thick armor. I do not know or can guess how the weapon manages to shoot rapidly without frying the coils but i imagine that if they have created a yamamoto cannon that shoots a highly concentrated energy at a high velocity to a destructive force. then obviously their science level and technology level must be more advanced than ours. Plus it is a game and some of the reasouces are not even known on this planet. So as to say the game technology in the game are far more advanced and also it is make believe so far.

    • Jackie Fauble

      I totally agree and that is how my gun concept works!

    • Nick

      This is not really practical because even a small amount of gun powder (think of a 22-short round) can pack a fair amount of power and the gun powder and electromagnetic energy would not add enough to each other to make this practical.

  4. Chris Modlin

    I always wondered why they used projectile weapons instead of lasers or energy weapons…then again nothing fits better with the “Badass Terran Marine” persona better than some good ol’ fashioned machine guns

    • Jackie Fauble

      One reason they probably didn’t use lasers is because a simple mirror can deflect it! And it also has to deal with refraction, more reflection and even absorption. But i don’t see why not to use a directed energy weapon like a particle cannon!

      • Thepenguinmaster

        Simple mirrors dont reflect lasers, You need a very clean and pure polished copper surface. A imple mirror would even burn through. I used to program and operate laser cutters for years.

        Also the benifit to a gauss rfle as a sniper rifle isnt the velocity of the projectile, but the lack of a bang.

        One thing that tends to give away snipers is the sound of the bullet fire. A lot of work goes into reducing the noise.

  5. Jackie Fauble

    You really helped me Ryan! I dream of being an engineer and I am a great terran player in SC2! I will definitely use this information.

  6. Brian

    maybe the case are
    1) the energy source for the coils using (insert techno babble)
    2) are coolant for coils
    or a combination of both

  7. Joshua

    The power source probably comes from the suit itself. Judging by the heat exhausts, they are probably burning some fuel hugely hot. Their gloves could have a simple connector points that link into the gun, making it interchangeable, upgradeable, and replaceable.

  8. Tim Fowler

    Jackie a mirror doesn’t work all that well as a defense against lasers. The mirror can not reflect all of the energy from the laser. Even if it gets 99.9%, the .1% percent is likely enough to degrade and then destroy the effectiveness of the mirror rather quickly. Maybe if the laser is weak, just barely strong enough to destroy the target and only then after dwelling on the same spot for awhile, a nearly perfect mirror made out of tough material might provide some minimal defense, but in most cases you can’t count on mirrors doing much to help you once lasers advance to the point where they are of significant military utility.

  9. Morgan

    I am sure that the casings themselves are the capacitors that would be used to fire the gun, thus not needing an external power source, or an internal battery.

    • Smog

      yeah!

    • Nick

      The casings, as was said before, are just a cool factor and probably just used to indicate the volume of bullets fired. A single-use capacitor would STILL require a power supply to charge them up. If you charged the capacitors during manufacturing, in a few minutes the charge on the capacitors would have leaked off and need recharging. It is imperative that the gun charge the capacitors. Also, it makes no sense to use a capacitor once and throw it away; it is best located in the gun. Finally, the capacitors are discharged through a coil in the gun, so again need to be in the gun. You can not have the coil attached to the bullet that it accelerates.

  10. Liquid HuK fighting

    Ok… Nice science words

  11. wackaa

    not to be a dick but starcraft and starcraft 2 were inspired on spaceship troopers were they the gauss rifle as you described which were used in starcraft later on the cinematics became better and the audience wanted more awesome in their games making your terrans criminals so if you would liked a normal gauss rifle in your game you just keep playing starcraft

  12. passerby

    the spent casings could actually make sense if these work similar to the railgun in the old Outpost 2 game where a chemical charge is used to generate a majority of the electricity needed thereby also removing the need for the rifle to have a massive battery pack.

  13. Nealius

    look if the casings were the chemical charge how does it convert into electricty for the coils and why in the game does the gun have a mussle(spelt wrong) flash. The answer to this problem is quite simple the c14 works like a regular gun, with gunpowered casings and all why because gun powered is the most reliable propoulsen method and as a soldier you always want reilablty over power, however there is a limit of how much recoil force a soldier can take so i belivie the gun is a hybird and use the gauss coil system as a secondardy propolsion method why because as the host said gauss coils are not reilable they over heat and wear out quickly. but to use it as a secondary system would improve its over heating and reilablty because it is doing hardly anywork

  14. Braden

    Current hypervelocity railguns have a huge muzzle flash from plasma generated somehow (I think it’s the super high air resistance of a projectile going that fast) and I would think the casings were heat sinks that the gun pumps waste heat into, or like some other people mentioned little power sources. Anyway in realworld normal guns the casings have two important secondary effects, 1 is removing heat so you can shoot longer (most of the burning powders heat is conducted to the casing) and 2 to keep a pristine driving surface on the bullet so that it doesn’t damage the barrel or fly crooked.

  15. PhantomMaelstrom

    Wow… that was clever… I didn’t know it exist in real life, at least, in a scientific experiment. I guess the guys at Blizzard did their research before making the game.

    • dickjohn

      More like they didn’t do their research.

  16. vaevictis

    i’m only in grade 10, but i have taken enough physics courses to understand fundamentals of the laws of motion. the starcraft wiki says that gauss rifles generate great recoil and that marine armour suppresses it. also they make loud sounds. if these rifles run on electromagnetic principles of some kind, shouldn’t there be no recoil and minimal sound?

    • Ryan

      The recoil just corresponds to how hard you are pushing on the projectile, so an EM gun will still have lots of recoil. It will be lound too, even though it doesn’t have gunpowder exploding, the bullet is going faster than sound so it will make a sonic boom.

      • vaevictis

        I see. I didn’t think that an EM gun would “push” the projectile in the traditional sense though. Thanks for clearing that up.

  17. Humza Hashmi

    You know, I might be considered an extreme idiot for saying this, but I think it’s perfectly plausible to have a computerized component in the gun to automatically stop the current in the coils, projecting the bullet successfully, in quick succession. Depending on the speed at which the bullet is released, a machine could reload another, turn on the current, and fire the bullet pretty quickly. This could easily explain the high firing rate. As for overheating, this is the future, and it is perfectly plausible that, in the future, extremely heat-resistant, electricity conducting metals or metal alloys have been discovered and used for the coils.

    • Eric

      This was exactly my though regarding the timing of the coils.

      As for overheating and conducting, carbon nanotubes are near perfect conductors and they’re heat resistant to at least 2000 degrees Celsius. Not completely perfect, but vastly more so than traditional conductors.

      Perhaps I’m just a naive 17 year old though.

  18. Benchkey

    Well, they walk around on friggin’ char, and can stand at an arm’s length of a forest fire. If those -suits- are incredibly heat resistant (among other things), why shouldn’t the coils be? As for power.. Researchers have -already- developed ways to turn body heat into electricity to use on appliances like phones. Take that tech 30 years further and voila. Heat generated == Power generated == Enough power for high rates of fire, for longer periods of time.

    • Jimmy

      To be perfectly honest (and I know this is kinda late), that would need some seriously condensed shiz to work – energy transfers are not perfect, and converting heat into electricity generally use several energy transfers anyway. Therefore, you would need to have a water-pack to convert to steam (and a condenser to turn the steam back to water again), and that steam would need to drive a turbine.

  19. Ronnel

    Well I agree with the hybrid theory about the gauss rifle since it also very possible. Plus since this IS the 26th century, computerization of the internal systems of the gauss rifle would be relatively simple in order to control the current into the coils and charging the capacitors. Plus you all have to account what kind of materials the terrans are using like miniature high temperature superconductive coils and high density power cells.

    To Jimmy March, not exactly. There are already direct heat-to-electricity conversion today like thermocouple and the new thermionics. (Yes those are actual terms, not just techno babble.) In this weapon’s case, the conversion system would make the power distribution system (not the power supply) more efficient. If the heat is turned into electricity, it can augment the already existing power supply thus less power needing to operate the weapon.

  20. Marine

    It only ejects spent casings depending on the design. An if you say it takes at
    East 10 seconds to recharge, that is using that is using the today’s technology. Have you ever thought of it recharging faster because of future technologies?

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