Introduction: MR-1.2 Coilgun (UPDATE: NEW INTERIOR PICTURE)

About: I love tinkering with anything and everything I can get my hands on. I also enjoy high adventure outdoor treks and relaxing in the shade at 14,000 ft. I am a sophomore at Rensselaer Polytechnic Institute, ...

A coilgun that I built. It started as a prototype and I decided to put it in a gun body. I then continued to make improvements from the MR-1 to the current version the MR-1.2. I have not done the math but I intend to do some tests and figure it out soon. Please pardon the rough appearance since this was only a temporary design to house the components.

The MR-1.2 features a two sectioned capacitor bank, new safety insulation, a relay, a safety charging switch, a four layer coil, 3x AA power source (parallel), extra ammo tubes, and a laser sight (actually sighted in).
Gun fires with surprising power. ( If you really want to know ill give you the specs to beat me to the calculations)

I will continue to work and build new guns (much better looking too)
any questions feel free to contact me .

Instructable / video to follow if requested

Charge time: approx 30 sec with 3xAA (longer with less)
Cap bank specs : 14 X 100 uf 330v caps (average of 80-120uf caps)
Coil approx 40mm x 4 layers (inner diameter is bic pen tube)
Relay runs off nine volt with push-button switch
Charging circuit modified to auto-charge
Rounds= 2-3 cm nails/screws (experiments used 6mm airsoft bbs to adjust round placement)

Disclaimer: I accept no responsibility at all for what you may do with this information or any damages/injury/death that may occur.This project uses DEADLY electricity as well as high speed projectiles. Do not under any circumstances try this unless you are trained with high voltage electronics. BE SAFE!

Please note before even considering a similar project: These are very dangerous, not even considering the projectile danger, the electricity is enough to kill you many times over. I use many precautions while working and I have the experience necessary to keep me safe. I do not allow anyone else to use the gun dangerously or open it up. Just in case, I encourage the use of a rubber glove when others are using this just in case (I don't want others to be harmed by my work ever and I alone have the responsibility to decide my own safety and use at my own risk). As for the projectiles, I treat this as a real gun and use full gun range safety procedures. Projectiles will hurt and could be very dangerous. Finally, please don't let this disclaimer get you down, just be safe and have fun!

cheers and please rate and comment!



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    If I'm using four 3300uF capacitors and an 9V power supply, does that mean the energy in joules would theoretically be:

    (9^2 x 13200) / 2000000 = 0.5346J?

    I don't know what a coil gun is, but if it is anything like a rail gun, I then I know what it is. A video would be good, but only if it is in Google Video. My computer doesn't agree with the Youtube video player.

    4 replies

    To be technical, a rail gun and a coil gun are different. They both use bursts of of high voltage electricity, but the means of propusion is different. A railgun uses an expanding arc of plasma to propel a metal slug using the gases produced when the arc travels through the rails/slug. Using a similar electronic capacitor setup, a coil gun lets that burst of electricity run though a thick coil creating a very strong electromagnetic field to put it simply. this field attracts the metal slug (sucks it in so to speak) and then, if timed properly, shuts off when the slug reaches the maximum magnetic field in the coil. the slug then continues with the kinetic force that has been induced into it. I know its complicated but I hope this clears it up. If I do post a video I will post in both formats. cheers, Mspark400

    Actually I think a railgun produces an electro-magnetic field. I forget what it's called. The (someones name) effect.

    lorentz forces effect.

    which is more important in determining the energy produced by the coil gun, the number of microfarads a capacitor has or the number of volts a capacitor can hold?

    1 reply

    volts, as the joule formula is V² . C / 2.000.000, where V is capacitor voltage and C is capacitance in uF.

    lolz i managed to get mine to fire once with an input of ~9vdc off a reg power supply then it died but dang it shot good one question tho did you put ur caps in series of parralel... ive done both and dont seem to get much of a difference. and a side note you can safely run the circuit at 3vdc w/o much harm to the transistor if you feal compelled you can aways attach a heat sink to the transistor which will help its lifespan. but any ways i like the idea of parralle battteries.

    1 reply

    If you put caps in series, the capacitance is lowered. If you put them in parallel the capacitances  are  linearly added.

    Hello and thanks for your interest,
        Unfortunately I am unable to really see your connections with the link provided. Also, the charging circuit puts more than 400-1200 volts (depending on input voltage.) Your caps have a  low voltage rating. Charging such caps comes with extra concern. I would suggest photo flash capacitors from the cameras or an online source.  However, several other instructables go into greater detail about these circuits so all problems should be relatively easy to clear up. If you have more questions feel free to ask.,

    I came.

    Seriously dude, this is amazingly awesome.

    Now you need to get one of those laser tag rifles and make another, more powerful coil-gun.

    pfd? surely you dont mean a personal flotation device? cheers, mspark400

    I believe he means PDF. The printable, book-like format of 'ible.

    yours looks like it would fall apart any second. you should have had a bigger container.

    1 reply

    to be honest the thing is dead solid. cheers, mspark400

    I have used an auto car coil for for power for my coil gun. It gives me all the power I need.

    Do u think the circuit board will be able to handle 25 330v capactiors (8250v) and if so how much punch do you reckon the projectile will have?