Rotary Electric Gun Might Not Put Your Eye Out, Kid

This one is clearly from the “it’s all fun and games until someone loses an eye” file, and it’s a bit of a departure from [Make It Extreme]’s usual focus on building tools for the shop. But what’s the point of having a well-equipped shop if you don’t build cool things, like this unique homebrew electric gun?

When we hear “electric gun” around here, we naturally think of the rail guns and coil guns we feature on a regular basis, which use stored electric charge to accelerate a projectile using electromagnetic forces. This gun is much simpler than that, using purely mechanical means to accelerate the projectiles. The heart of the unit is a machined aluminum spiral from an old scroll compressor, which uses interleaved orbiting spirals to compress gasses. This scroll was cut down to reduce its mass and fixed to a complex shaft assembly allowing it to spin up to tremendous speed with a powerful electric motor. A hopper feeds the marble-sized ammo into the eye of the scroll, which spits it out at high speed. Lacking a barrel, the gun can only spew rounds in the general direction of the target, but it makes up for inaccuracy with an impressive rate of fire — 100 rounds downrange in two seconds. It’s pretty powerful, too, judging by the divots in the sheet steel target in the video below.

Like all of [Make It Extreme]’s build, a lot of effort went into this, and it shows. Their other fun builds of dubious safety include these electromagnetic wall climbers and these “Go Go Gadget” legs.

24 thoughts on “Rotary Electric Gun Might Not Put Your Eye Out, Kid

    1. As someone who walks through a large machine shop to get to my workplace, it was interesting to watch.
      I think it was a well done video, too bad more videos aren’t done that way.

  1. Nice job. But it wont stop the zombies.
    Need fast and more power. ( Exploding pellets might help.)
    You have to save us from the zombies.
    Please help use you are humanity’s last hope.

    1. Flechettes instead of pellets. Aim for the neck, the head will drop right off after a 20-round burst.

      Not that I have experience in that field….just speculating.

      I liked the idea in “The Day of the Triffids” – a gun throwing a spinning, sharp-edged metal disc to decapitate Triffids.

    1. I guess the feeder works as a barrel and that the direction can be calibrated by adjusting the fixed scroll?
      Can’t get much precision but then I don’t think they ever intended to have a precise weapon ;P

    2. As others have said, the top piece has a scroll race which spins rapidly. The bottom plate has a straight race that does not move. The races are both sized to be roughly half the diameter of the ball. Thus, for the ball to exit the device, it gets guided along the straight race as the scroll race pushes it out to ever widening circumferences until it exits. Here’s a slightly different execution, but a similar concept from the slingshot channel that illustrates things (it’s basically a reverse configuration):

      1. Ah, that explains it. I wasn’t paying close attention and I didn’t realize the spinning piece was the one with the straight radial cut. Joerg’s model really clarified that and I knew what to look for when I went back to the original video. Thanks!

  2. BTDT – US Military calls it the MPDS or Multiple Projectile Delivery System nicknamed “DREAD”. Here’s some limited backgrounding on it:

    New Scientist (. com)
    11 May 2005
    Centrifugal weapon could deliver stealth firepower

    By Will Knight

    A gun that spits out ball bearings after spinning them to extreme speeds is being developed by a US inventor. The novel design has already caught the imagination of some defence industry experts.

    The weapon, called DREAD, was invented by Charles St George, a veteran of the US firearms industry who founded the company Leader Propulsion Systems to promote the idea. He claims a major US defence company has shown an interested in developing it further and has produced a promotional video showing a prototype in action, which can be seen here (Quicktime). He says a new prototype will be developed in August 2005.

    The gun consists of a mounted circular chamber that spins the metal ball bearings to high speed. A release mechanism on one side spits the balls out one behind the other, a handful at a time.

    St George says the projectiles travel at around 300 metres per second upon release from the weapon, about the same speed as a handgun round. He claims a fully developed DREAD gun would be quieter than a conventional gun, less prone to malfunction, and could contain more ammunition.

    DREAD also releases its balls in extremely rapid succession, which allows it to unleash formidable firepower against a target. Promotional material for DREAD states: “Due to its extraordinary high rate of fire capability, it delivers its bullets 8.5 millimetres apart, thereby delivering more mass to the target than any other weapon.”

    Overwhelming and devastating

    St George would not specify the range or accuracy of the most recent prototype or explain precisely how the system works, because he says this information could be commercially sensitive.

    But a patent issued to him in February 2003 has been found by Marc Abrahams, editor of science humour magazine Annals of Improbable Research. It refers to a “Weapon for Centrifugal Propulsion of Projectiles”. In this design, balls are stored inside a series of narrow chambers that radiate from the centre of a circular chamber and which are rotated with the chamber at high speed.

    A mechanism beneath each narrow chamber automatically manoeuvres a single ball into a smaller compartment at near its edge. When the trigger is pulled, these balls are released into a guide rail and shoot from the disc rapidly, from a hole at its edge.

    “The system seems absolutely feasible,” says David Crane, editor of the website The weapon could strike targets with “overwhelming and devastating firepower ” we’re talking about total target saturation,” he wrote in an article posted to the site.

    Terry Gander, who edits the defence industry journal Jane’s Infantry Weapons, adds that similar concepts have been developed in the past. But Gander notes that these have had low projectile velocity and have been proposed as crowd control weapons. “It all depends on the sort of power source you have,” he told New Scientist. “I’d be very interested to know what its range is.”

    But Abrahams finds the idea outlandish. “Anything that seems so far beyond anything else is worth a moment’s thought before you completely gulp it down,” he told New Scientist. “It is way out on the side of the scale that deals with high levels of imagination.”

  3. Because it’s hopper-fed it can’t be used sideways gangsta-style. (c:

    Just kidding. It’s an awesome build. For most of the video I couldn’t tell what they were trying to do. I mean I knew they’re building a pellet gun, but I couldn’t tell the design.

    1. These guys look like the bored engineers from the West Hartford CT machine-shop plant that builds the DREAD for Colt Firearms US defense contractor down the block or two. Some how they got a hold of the patent (#6520169 dated 2003) and wanted to duplicate St George’s invention but a mini version. Impressive work and looks like a paintball gun too. You’re right, you can’t hold it Center Axis Relock style or the bearings won’t have gravity-feed anymore. They wont fall out though.

      Supposedly USAF can use this for satellite-killers. No recoil to throw off sat attitude. However gyroscopic forces will throw off the bird a bit if no counter rotation employed. I really don’t know how these guys found the time to dabble with this project.

      They are Mike and George M. from island of Cyprus. They are the coolest machine shop guys I’ve ever seen. They love the MiGtronics welders. They can make almost anything you can imagine.

        1. Rollyn01- Just like the new USN/USMarines KAMAN robot helicopter (KMAX), you have to have counter-rotating rotors to mitigate gyroscopic rotation. It does not have to be on the main ball bearing chamber, just above or below it to prevent the thing from rotating the whole satellite. There is no recoil too as it acts like a David and Goliath rock sling.Only the rocks are metal golf balls with dimples.The trauma to the target is massive and mostly silent in-flight (when slowed down from super-sonic).

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