Homemade coil gun

[dragon]

Damn thats cool and thats with off the self components. One step closer to battlefield ready coilguns.

The battery-powered projectile-blaster took 2 years to complete, according to its creator, YouTube user Larsplatoon, and it packs four capacitor housings, a 2-volt high drain battery, and an old cell phone regulator board to keep it from overcharging.

Larsplatoon dubs it a "1.25kJ Coilgun"—that's some 78 times the amount of energy lethal to human beings—though Make points out that that's likely the capacitor's theoretical maximum output. By their calculations, 1.25kJ of muzzle energy would give the coilgun more oomph than a .45, and while it certainly has no problem tearing through those glasses, it's not exactly shattering them into a million pieces.

Still, as far as DIY arms go, this one is a little bit more intimidating than the rubber band gatling gun. [Make via PopSci]

link

[Temujin]

Pretty impressive for young guy doing DIY.

I could see the military or DARPA interested in taking a look at this just out of curiosity. Irregardless, he has some impressive skills.

[Seggybop]

Coilguns are super simple to make. I assembled one as an in-class demo last week using camera flash capacitors last week, even. This guy did a rather impressive job on the housing though.

They're kind of horribly inefficient, so don't expect them to be used for an actual weapon system any time soon.

[Zixinus]

I showed this to my electric-engineer father. He smiled. It's actually pretty hilarious.

They're kind of horribly inefficient, so don't expect them to be used for an actual weapon system any time soon.

Yeah, that caught my eye. 1-3% efficiency? That's pretty horrible.

[CaptainChewbacca]

Pretty impressive for young guy doing DIY.

I could see the military or DARPA interested in taking a look at this just out of curiosity. Irregardless, he has some impressive skills.

Man-portable coilguns have been possible for about five years now. The problem has been that;

1. They can't shoot as far as a gun.
2. They can't shoot as many rounds per minute as a gun.
3. They aren't as durable as a gun.

Its a cool proof-of-concept, but don't expect these to replace gunpowder any time soon. Personally, I'm curious as to what muzzle velocity he got. Given that one of the shots bounced off the microwave, it seems to be just a really expensive slingshot.

[Temujin]

Pretty impressive for young guy doing DIY.

I could see the military or DARPA interested in taking a look at this just out of curiosity. Irregardless, he has some impressive skills.

Man-portable coilguns have been possible for about five years now. The problem has been that;

1. They can't shoot as far as a gun.
2. They can't shoot as many rounds per minute as a gun.
3. They aren't as durable as a gun.

Its a cool proof-of-concept, but don't expect these to replace gunpowder any time soon. Personally, I'm curious as to what muzzle velocity he got. Given that one of the shots bounced off the microwave, it seems to be just a really expensive slingshot.

No, I'm not actually expecting the military to start buying these, but they have a history of looking into new ideas and novel concepts (hell they blew money on remote sensing and other psychic crap). However, I did not realize that people had been making coilguns so small. The smallest stuff I had seen still was the size of a small artillery piece. But then those are purposely designed to work at higher power levels and/or serve as technology testbeds for weapon systems.

[Aaron]

Pretty impressive for young guy doing DIY.

I could see the military or DARPA interested in taking a look at this just out of curiosity. Irregardless, he has some impressive skills.

Man-portable coilguns have been possible for about five years now. The problem has been that;

1. They can't shoot as far as a gun.
2. They can't shoot as many rounds per minute as a gun.
3. They aren't as durable as a gun.

Its a cool proof-of-concept, but don't expect these to replace gunpowder any time soon. Personally, I'm curious as to what muzzle velocity he got. Given that one of the shots bounced off the microwave, it seems to be just a really expensive slingshot.

I doubt it even got anywhere near the velocity of a .22. He had to fire three rounds to get through three glasses. Cool project though.

[Starglider]

Single-coil coilguns are quite straightforward. They consist of a high-powered solenoid that you put a large current pulse through; they're easy to make if you have a big bench power supply, most of the work here was in the compact packaging. For higher velocities and efficiencies you need a multi-stage coil gun; the more stages, the better (ideally you would be switching individual windings as the projectile moved through the accelerator). These are much harder to make.

[Zaune]

Its a cool proof-of-concept, but don't expect these to replace gunpowder any time soon. Personally, I'm curious as to what muzzle velocity he got. Given that one of the shots bounced off the microwave, it seems to be just a really expensive slingshot.

Definitely with you on that one. YouTube kills this computer, but from the description of its effects I'd guess he's getting about the kind of muzzle velocity you'd expect from a CO2-powered airgun in a package that looks like it weighs as much as an AK47. I doubt it'd produce enough recoil to reliably power a self-loading action either.

[Starglider]

I doubt it'd produce enough recoil to reliably power a self-loading action either.

No need, it's powered so you could just use another solenoid to work the action.

[HMS Conqueror]

1.25kJ is about comparable with a rifle bullet. A weak rifle bullet, on a bulkier, more fragile, harder to reload weapon. Not sure about "78x energy lethal to humans"... whatever that even means. 16J you could easily put into a tennis ball.

In many ways this is probably an easier way of making a firearm than going down the black powder route given the relevant laws, though.

[Zaune]

In many ways this is probably an easier way of making a firearm than going down the black powder route given the relevant laws, though.

Which relevant laws? Its power-to-weight ratio is probably inferior to a spring-powered air rifle, and I can buy one of them over the counter with nothing more than ID to prove I'm over 18. Hell, a paintball gun full of ball-bearings would be more lethal than that thing.

[Starglider]

Yeah, that caught my eye. 1-3% efficiency? That's pretty horrible.

Even a very basic three-stage gun achieves over twice the efficiency.

[Sea Skimmer]

1.25kJ is about comparable with a rifle bullet. A weak rifle bullet, on a bulkier, more fragile, harder to reload weapon. Not sure about "78x energy lethal to humans"... whatever that even means. 16J you could easily put into a tennis ball.

That’s actually about what the US military defines as being the energy of a ‘dangerous fragment’ but they are assuming a very high speed very low mass chunk of metal. Also dangerous and lethal aren’t the same thing, and I suspect someone noticed that spec and misinterpreted it. The slower the projectile the less its total energy matters until you get a situation in which someone stops a several ton car from rolling slowly at them.

[HMS Conqueror]

In many ways this is probably an easier way of making a firearm than going down the black powder route given the relevant laws, though.

Which relevant laws? Its power-to-weight ratio is probably inferior to a spring-powered air rifle, and I can buy one of them over the counter with nothing more than ID to prove I'm over 18. Hell, a paintball gun full of ball-bearings would be more lethal than that thing.

In many countries it is illegal to buy or own explosives as a general rule, and purchasing ammunition requires a firearms license. Maybe this is not the case in the USA. I think under UK law, the coilgun itself may actually require a firearms certificate, but I am unsure about that. Spring and air guns over a certain muzzle energy do.

btw, this really isn't a toy gun. It has about 75% the muzzle energy of the 5.56x45mm NATO rifle round (standard issue for US, UK, etc. military), and more than twice that of a 9mm pistol round.

That’s actually about what the US military defines as being the energy of a ‘dangerous fragment’ but they are assuming a very high speed very low mass chunk of metal. Also dangerous and lethal aren’t the same thing, and I suspect someone noticed that spec and misinterpreted it. The slower the projectile the less its total energy matters until you get a situation in which someone stops a several ton car from rolling slowly at them.

I've seen similarly ridiculously low quoted "minimum deadly energy" figures before. I believe they're calculated from the amount of energy needed to cause a bruise that could potentially result in a fatal blood clot - an extremely unlikely event. So the usefulness of this measure is fairly minimal, since these energies are routinely exceeded playing sports, and all manner of other perfectly legitimate activities.

Judging by the size of the slug, I think you're probably right about the speed, though. It's probably very sub-optimal resulting in lower penetration than the energy would indicate when compared to rifle rounds. Still, I don't see any reason why it couldn't be made smaller; I assume that the chap wasn't actually trying to create the most deadly weapon possible with the materials, as opposed to just powerful.

[Zixinus]

The 1.25kJ figure is that of the maximum performance of the capacitors, not the energy going out by the bullet itself.

[CaptainChewbacca]

I had a thought about this; How would this weapon be legally classified? Is it a firearm? An industrial implement? An electronic device?

If I was carrying this down the street, could I be arrested for openly carrying a weapon?

[Sarevok]

You easily kill a man with a single shot from a well designed coilgun. Its a weapon.

[LaCroix]

Dependent on wording in your laws, it could be a firearm. Most countries use the definition of stored energy used to propel a projectile, which results in a crossbow also being considered a firearm, as it can be kept ready to fire. (That's the reason why bows are usually not considered firearms/weapons, as you have to draw and release the projectile.)

[Zaune]

No idea how British firearms law would treat one of these things, but going out in public with it loaded and powered up is a surefire way to get sent down for carrying an offensive weapon.

[Sky Captain]

You easily kill a man with a single shot from a well designed coilgun. Its a weapon.

Could a coilgun with single coil accelerate bullet fast enough for a lethat shot? With multiple coils it could, but those designs are more complex and bulkier and harder for amateurs to build.

I think if you want to shoot someone, but cant obtain a real firearm it would be much easier to build a primitive rifle from steel plumbing pipe rather than design and build an elaborate coilgun.

[General Zod]

You easily kill a man with a single shot from a well designed coilgun. Its a weapon.

Could a coilgun with single coil accelerate bullet fast enough for a lethat shot? With multiple coils it could, but those designs are more complex and bulkier and harder for amateurs to build.

I think if you want to shoot someone, but cant obtain a real firearm it would be much easier to build a primitive rifle from steel plumbing pipe rather than design and build an elaborate coilgun.

Define "lethal". Something that pierces a vital organ is going to be lethal enough, but it won't be enough to kill them instantly. The gun in the video looks like it's plenty lethal against an unarmored target that's not too far away.

[Seggybop]

It's not really that hard to make a multi-stage coilgun; if your barrel is transparent you can use phototransistors to detect the position of the projectile and power up each coil at the correct time.

The efficiency will still be quite horrible, so if you need to actually hurt someone badly try punching them instead.

[Chaotic Neutral]

The efficiency will still be quite horrible, so if you need to actually hurt someone badly try punching them instead.

If you could tell me where to get a bow that fires boxing gloves, that'd be great.

[CaptainChewbacca]

I emailed the BATF about the legality of owning or operating such a device, or carrying one down the street.

Since no explosive is used to propel the projectile, it does not meet the definition of a “firearm” under federal law.

As long as the muzzle diameter does not exceed ½ inch, the device would not meet the definition of a “destructive device” as such is defined under Federal Law.

Provided that the muzzle diameter of the device is not over ½ inch in diameter no license is required to build this device, and its creation and possession would be unregulated by our agency.

ATF – Enforcement Programs and Services

Good to know. I'm guessing when they say 1/2 inch muzzle, they're talking about the bore.