Homemade Semi-Automatic Coil Gun

Daniel Eindhoven has build a very sci-fi looking semi-automatic coil gun.

 Coilgun 378

The pistol uses a single magnetic coil to pull the projectile out of the gravity fed magazine and towards the coil, thereby accelerating the projectile. It then shuts off the coil and the projectile, because of its momentum, continues on its course through the barrel and out of the muzzle.

This gun shoots 648 grain projectiles at a speed of 100 feet/second, which works out to be 14 ft/lbs of energy. To put that in perspective, it is about half the muzzle energy of a .22 CB Cap and 10% of a high velocity .22 Long Rifle’s muzzle energy. It would certainty bruise the skin.

Like laser guns and rail guns the practicability of coil guns is limited by the amount of power they require. Until we can safety store vast amounts of electrical energy in a small package, carrying around energy in the form of smokeless power will be the preferred method of reaching-out-and-touching-something.

Hat Tip: Engadget

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • R.A.W.

    Knock yourself out:


  • Until we can safety store vast amounts of electrical energy in a small package…

    … And disperse the absurd amount of heat high-yield electromagnetic coils generate…

    In any case, though, for being a home-made project, that is pretty darned impressive.

  • Heat, from a milliseconds-long pulse? How hot could it get from one shot?

  • Valhalla

    Yea… though I don’t see how he could store enough energy for a real coil gun, in which the projectile does not touch anything once in the barrel, but is held and propelled by magnetic force. I’d think a rail gun or traditionally fitting barrel section to allow for a ‘pulse’ of energy to travel down the barrel would work better.

    Just a thought.

    Hey, Steve, if you want I can email you a paint picture of what I mean.

    It’s kinda a firearm…

    • Valhalla, yea, in this gun it is just using one coil to push the projectile so it would, I am sure, touch the barrel. From what I understand of these guns, and my limited knowledge of physics, I think you are right. The lack of friction it a major advantage.

      On the other hand, they can’t spin the projectile. Or can they?

  • Griffin

    This is the future…

  • Cmathews

    I made a coil-gun for my sophomore year science project. I used the flash assembly from a disposable camera and a coil of magnetic wire. Its a great way to experiment with electromagnetism. I was, however, approached by the SRO (student resource officer) and thoroughly questioned about my “projectile weapon”. I am very impressed by this one, nice find!

  • So when they gonna regulate our energy weapons? LMFAO The garage projects are going to out do everything soon I figure if stuff like this is doable. Have to start somewhere.

  • Valhalla

    Well, a magnet gets equal amounts of N and S, so it would split down the middle. If you then got one wire/rail that would pull only S and another for N and coiled them like DNA, then the bullet could go down the middle and be spinning.

    My other idea is a bit more like this:

    => bullet

    barrel sections are electrically magnetized until bullet passes into them. At that time they stop, so for a while all are pulling, then all but the first, second, third, etc.
    Don’t know if this one could be made to spin.
    |^^| <- spring

    • Valhalla, cool. What if one one half of the projectile was made from a material that was either magnetically charged or a material that was not as attracted to a magnet as the other side. Could that induce a spin?

  • Valhalla

    Should work…

    / \
    | |
    \ __ /

    Take this ‘barrel’ as an example. Half of the projectile is magnetic, the other is not. Using the previous idea and this, it should get a good twist.

    Anyway, each of the ‘sides’ (Barrel sections would be smaller and all that jazz, most certainly not to scale or anything) act by themselves. Barrel Section 1 orientates round with pull from the top. S2 is one side to the right, etc and maybe going all the way around. Maybe the increments could get bigger as it goes along, as the round would be going faster.

    Though I didn’t mention it before, I had envisioned rifling anyway.

    But the best part of a coil gun would be what you could shoot. Holy water for the vampires, anti-T viruses for the Zombies, pork fat for terrorists, blah blah blah. And shrapnel rounds, willed with crushed glass or something that would get around under the skin.

    • Valhalla, let me know when you have built one 😉

  • Valhalla

    Gah. Barrel didn’t work. Here goes with periods instead of spaces.


    good enough I guess.

  • Valhalla

    Have to wait a while then… gonna need some uber batteries.

    Maybe get some steel pipe and hack saw it.

  • kunal

    can we use multistage with smaller projectiles and use rechargable li-ion (cellphone) batteries.they r usually rated 3.7v abt 1.1amp. and integrate them into the magazine. so when u change the magazine u change batteries too.reuse magazine by inserting new projectiles and charging batteries.

  • Mr John Smith

    Hmm, interesting. That’s just a coil gun. It’s when they try to make a gauss rifle that size you should be scared.

    Difference is how a Gauss rifle (don’t look at Wikipedia, they got it all wrong!), operates. Both use magnes, it’s just that in a “real” Gauss rifle it uses electromagnets in series, around a thousand or more to fire off a large projectile.

    The ones that do exist are big bore, and to try and make a small one is.. well it’s impossible without the correct tools. Not to mention how accurate the calculations have to be measured, and also the barrel has to be exact. Only the combination of say a scientist in physics and a weapons smith might be able to “cook” something together.

    Smallest diameter I have ever seen on a Gauss was about 12″. It was a prototype however, and I guess that the idéa of having a smaller powerplant to charge it was out of the question.

    Both a coilgun and a Gauss rifle do accelerate the projectile, but a Gauss (real Gauss) does it better.

    /J.Smith Defiance Industries.