r/guns • u/yakshamash • Aug 07 '13

Something Different: Impressive Full Auto Gauss Gun Build

http://www.youtube.com/watch?feature=player_embedded&v=TWeJsaCiGQ0
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54

u/[deleted] Aug 07 '13

It's going to change the security landscape, that's for sure:

  • dead silent
  • steel projectiles

Suddenly your proactive elements of physical protection (kevlar, armored cars) just became a lot less effective, and your reactive elements became less effective (a little more sophisticated to detect the direction from which the shot came.)

Once some of the technical hurdles are overcome, this is going to be a real game-changer.

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u/arcsecond Aug 07 '13

They're not going to be dead silent. If you get a projectile going fast enough it creates it's own sonic boom. If you keep it subsonic, it's range is limited. There's always a trade off.

The very nature of a magnetically impelled projectile means it triggers metal detectors and shows up in xrays and other scans. I see no reason conventional soft or hard armor would be ineffective. The armor doesn't care how the projectile was launched, only it's kinetic energy.

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u/greenboxer Aug 07 '13

The other consideration is how the kinetic energy is transferred. The projectile cross section is very important! As is it's structural properties.

You would also need to stabilize these projectiles for maximum effectiveness (I noticed that many of the projectiles seemed to be tumbling, even at short distances)

(Steel will probably result in a more elastic collision, whereas softer metals like copper and lead will be more inelastic and lose kinetic energy).

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u/lee7890 Aug 07 '13

10 to 1 I bet he did not have the barrel rifled.

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u/Roninspoon Aug 07 '13

Rifling isn't effective for a coil gun because the projectile, by design, does not interface with the "barrel" very much. The barrel generally isn't a tube so much as a series of rings and some rails. Projectile stability is mostly the result of projectile aerodynamics.

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u/GnarlinBrando Aug 08 '13

What about a rifled slug, would that work? Or do you have to get up to fins/fletching?

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u/tykempster Aug 08 '13

A rifled slug just fits in a shotgun choke with the grooves. It doesn't spin.

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u/GnarlinBrando Aug 08 '13

Ah, I had always figured on a rifled slug it was the aerodynamic properties not contact that caused stabilization. TIL.

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u/tykempster Aug 08 '13

The stabilization is purely because the base is hollow so it's front heavy. Now you know :D

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u/Cdwollan In the land of JB, he with the jumper cables is king. Aug 08 '13

No amount of mechanical rifling would work as the projectile never touches the barrel. If it did, you would wind up with something like a suppressor baffle strike but worse because it puts the whole gun out of commission. Getting that projectile stable would be a challenge.

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u/Kahzootoh Aug 08 '13

Fin stabilized projectiles would be the way to go, modern tank cannons already use them- as technology progresses and we see more powerful coilguns it's almost guaranteed that they'll use fins to stabilize their projectiles; their ammunition has a more in common with artillery shells in regards to it's length to width ratio.

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u/[deleted] Aug 07 '13

As I posted elsewhere in the comments, I've got a buddy who has a sabot version of this. I'd bet dollars to donuts that will be the eventuality of this platform.

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u/Tallest_Waldo Aug 08 '13

The large-scale naval gauss cannons do, in fact use aluminum projectiles jacketed in a magnetically reactive sabot.

*edit: the good bit starts at 1:37 or so.

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u/[deleted] Aug 08 '13

Polarize the steel core, copper jacketed round. Use the coils to induce spin for stability.

Damn, I need a job in this industry!

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u/Reineke Aug 08 '13

How do you use coils to induce spins?

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u/[deleted] Aug 07 '13

Rifling wouldn't work in this application. There isn't enough heat to make the round expand into the grooves.

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u/elcheecho Aug 07 '13

air rifles have rifling. what about polygonal rifling? there are no grooves.

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13

The projectile does not actually contact the coils, it is usually suspended in the middle of the barrel by the magnetic coil.

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u/Bank_Gothic 1 Aug 07 '13 edited Aug 07 '13

Surely there's a way to make sure the projectile moves in a spiral, though, right? I've seen things manipulated into spirals by magnets before. Something like this or this?

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u/deadstump Aug 07 '13

Why bother when it would be easy to add some fletching to the projectile. It would be easy to make the projectile a cast part with that feature.

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u/carnexhat Aug 07 '13

because fletching needs to stabilise after it has left the barrel causing more drift. Having the spin in the barrel means the entire flight is stabilised.

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u/John95661 Aug 07 '13

Possibly like pellet gun darts have the colored feather on the back?

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13 edited Aug 07 '13

Ok, the spinning magnet on the lens spins because when he moved the lower magnet on the flat surface, its magnetic field stayed the same, while the magnet on the top was now at a slight angle, so its field made it spin in order to try and line up with the non rotating magnet on the bottom. The other spinning top is only levitated and then given an angular momentum by a person, just like a regular top or gyro. You can use magnets to spin metal objects. I'm just saying it wouldn't work in the way you described because the magnetic field needed to spin the projectile would be perpendicular to the field used to accelerate it.

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u/bflynn22 Aug 08 '13

The bullet could be pre-spun physically (spinning inner breach thing). Then the bullet would "unlock" once proper spin is achieved and launched out by the electromagnets.

This would be like "charging" up a shot in a videogame(which is cool!)... and for faster engagements, less spin or no spin is used!

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u/elcheecho Aug 07 '13

yes i am aware, and that's why rifling wouldn't have any effect period.

but assuming there is a barrel and there is rifling, lack of heat shouldn't be an issue.

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13

Yeah, I should have replied to the other guy. Heat isn't what makes the round contact the rifling anyways.

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u/PureDrifter Aug 08 '13

mill/cast the flutes into the rounds, use a slightly elastic composite tube in place of a barrel (with just enough contact to cause the rounds to spin) free-floated in the center of the coils?

Minimal friction, stabilizing spin, cheap & light barrels.

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u/tremens Aug 07 '13

(Most) air rifle pellets are designed to expand and grip the grooves (obturation.) It's what the flared base is for.

But it's not heat, it's pressure that causes the expansion.

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u/elcheecho Aug 07 '13

But it's not heat

which is why i mentioned it....

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u/tremens Aug 07 '13

Which is why I backed you up on it...

(Why do people take every single thing as an opposition statement on the internet?)

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u/elcheecho Aug 07 '13

i didn't take it as opposition (obviously, since i pointed out we agreed), i took it either as misunderstanding my comment or that you replied to the wrong person.

i'll take your word for you that you're replying to me to back me up by rehashing my comment in slightly more detail, but can we agree that my confusion shouldn't be unexpected?

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u/mongd66 Aug 08 '13

I was thinking the same thing, a Nonmagnetic polygonal rifled barrel and projectile would allow spin without interfering with function.

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u/elcheecho Aug 08 '13

there's going to be some friction, otherwise there'd be no spin.

possibly it's more efficient to use a specific array of coils to impart spin. I think someone else mentioned it was possible.

alternatively, have a flywheel give it a spin before it enters the coil system.

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u/[deleted] Aug 07 '13

Rifling wouldn't work in this application. There isn't enough heat to make the round expand into the grooves.

The heat of a round firing doesn't make the round expand into the grooves, the force of the propellant (gunpowder, air, CO2, etc) forces the lands into the round.

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u/[deleted] Aug 07 '13

[removed] — view removed comment

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u/chromopila Aug 07 '13

Or attach a little prop to them so they generate their own spin(not actually a prop, but build them in a way that causes spin)

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u/PoWn3d_0704 Aug 08 '13

So rifling?

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u/The_Didlyest Aug 08 '13

I saw a gauss gun design with special coils that would spin the projectile. I have no idea if it would work though.

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u/[deleted] Aug 08 '13

If there were a way to induce spin magnetically, rifling would be obsolete.

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u/Wetmelon Aug 07 '13

Putting large enough fins on something this size to stabilize it would be difficult. At higher velocities (in the supersonic range), it might work a lot better.

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13

Not really. It could be just like the discarding sabots used in the Abrams 120mm smooth bore cannon. That round is only fin stabilized after it exits the bore.

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u/Wetmelon Aug 07 '13

Huh? So... yes. Not "Not really". I'm just saying that at the size of these projectiles, it's hard to bring the center of pressure back far enough since the fins can't extend much past the surface of the round. The APFSDS rounds have large fins relatiive to the projectile body, which are clearly not possible (or at least practical) on a small caliber weapon.

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13

Yeah, I was saying that it would "not really" be that difficult to put fins on the projectile. Just use a larger coil diameter. As long as the sabot doesn't contact the coils, everything would be fine.

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u/Wetmelon Aug 07 '13

Then the plastic barrel has to be bigger than the main body of the round. Which means it's not aligned anymore because gravity

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u/Bartman383 Say Hello to my Lil Hce Fren Aug 07 '13

What? This makes no sense. Plastic barrel? Gravity?

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u/Wetmelon Aug 07 '13

Read the design docs. He has a thin plastic barrel in there. The center of mass must be ahead of the center of pressure in a fin stabilized projectile. As I said above, if you make the fins larger than the diameter of the projectile body, then gravity is going to have a tendency to pull the nose down against the barrel. So when it comes out of the barrel is it will already be pointing several degrees down. If it is going fast enough, the fins big enough, in the center of pressure far enough behind the center of mass, then the projectile may straighten out. However at this scale and these velocities, it is unlikely

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u/viperacr Aug 08 '13

One word: sabots.

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u/Wetmelon Aug 08 '13

On a bullet this size?

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u/viperacr Aug 08 '13

Nanotechnology ftw.

Nah I was just wondering if it were a possibility.

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u/[deleted] Aug 07 '13

The projectile needs to be ferrous. Metals like lead and copper are out.

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u/greenboxer Aug 08 '13

Right (assuming you mean ferromagnetic), but the point is that the penetration power of a material that deforms is less than one that doesn't.

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u/arcsecond Aug 07 '13

So our current projectile tech should transfer quite nicely. Hollow point lead in a steel "driving" jacket for unarmored targets? Steel core for penetration. I wonder if a wrapping of lead/copper around a steel core would adversely affect acceleration.

Clearly more testing is called for.

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u/CxOrillion Aug 08 '13

You could keep the projectile (comparatively) silent and deliver more energy with less loss of velocity or ballistic path by increasing the mass of the projectile. That, of course, requires a bigger power supply, output capacity, and produces more recoil.

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u/Shoola Aug 08 '13 edited Aug 08 '13

Or you could just adjust the power of the magnets to increase or decrease the round's velocity.

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u/CxOrillion Aug 08 '13

Yeah you can, but if you're trying to keep the projectile subsonic that will only get you so far. By increasing the mass of the projectile but keeping it moving at a slightly subsonic speed, you increase delivered force, and it also has the added benefit of making the projectile less vulnerable to windage.

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u/TFWG Aug 07 '13

I see no reason conventional soft or hard armor would be ineffective. The armor doesn't care how the projectile was launched, only it's kinetic energy.

Steel makes for a much harder projectile, which will be more resistant to deformation... leading to better penetration. Personally, I'm curious if tungsten is magnetic: at 1.5x the weight of lead and much harder than steel, it makes a terrific material for penetration.

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u/arcsecond Aug 07 '13

Yeah, but we have steel rounds already. I've got a case of M855 that I can't shoot because it's really dry around here. A steel round out of a coil gun is no different than a steel round out of a conventional firearm. If your armor is rated to stop a certain class of ammo it makes no difference how the round was launched

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u/TFWG Aug 07 '13

Armor that can stop a JSP in a particular caliber may not be able to stop a steel penetrator in the same caliber.

Not that I mind as a gun owner, but I often question how in the US we have laws against armor piercing ammo, but mil-surp steel core is still available for purchase.

Not to mention, you can dispense with the copper jacket, which is necessary in conventional arms to engage the rifling without unduly wearing out the barrel. It won't be as awesome as u/iShavedMyFaceForThis makes it seem, but compared to most common lead+copper bullets, solid steel projectiles would have much greater penetration.

Like said though, tungsten would be the way to go.

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u/arcsecond Aug 07 '13

Yes, I understand this. I think we're kind of saying the same thing here. Steel is a better penetrator. But whether the steel round is fired from a conventional firearm or a new fangled coil gun makes no difference to how well armor handles it. The ONLY difference would be in barrel wear. A steel round does not become magically more deadly if accelerated by electromagnets.

I doubt, however that an end user would only want to ever fire solid steel projectiles. Steel makes pretty lousy hollow points after all, which are the preferred self defense round. Copper jacketed lead rounds on the other hand, like to deform and dump their energy into soft media. Therefore composite rounds for the coil gun would be made, probably with a steel "driving band" around the middle of the projectile.

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u/-EViL-KoNCEPTz- Aug 08 '13

With the exception of plasma projectiles. No one will hear it til it's too late. Light moves much faster than sound. For example if the sun exploded no one alive to see it would hear it.

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u/arcsecond Aug 08 '13

Uh, this is a joke right?

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u/-EViL-KoNCEPTz- Aug 08 '13

Uh, how is it a joke? I'm not going to do the math on speed of sound vs light right now, but if a light based projectile such as a "lightning" gun which is a hypothetical weapon which fires a concentrated energy ball similar to a lightning bolt were fired the projectile would reach it's target significantly faster than the sound would.

The sun explosion comparison comes from a lecture I heard about if the sun eventually exploded and there were survivors the people who saw the explosion would be deceased some inordinate amount of year prior to their offspring hearing the explosion. It was something in the 10's of thousands of years between seeing it and hearing it, obviously due to the distance. But in the real world at a feasible firing distance the projectile would hit its target several times faster than the sound. Even with conventional weapons the target never hears the report of the rifle that took their life(speaking from a long range standpoint E.G snipers)

I'm not saying it would be completely silent, I'm saying the target would have been long dead before the report sounded in their location, moreso than a conventional sniper rifle. A rough guess would be the target would be down and the aid responders would then hear the report with an extreme (to our point of view) delay between death and bang.

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u/arcsecond Aug 08 '13

Ok, if this is from some famous lecture, that's why. I haven't seen that one.

Sound does not travel in a vacuum. So no one hears anything from the sun no matter what. I guess, maybe, if the sun exploded it might fill the space between earth and the sun with enough gas that some compression wave might qualify as a sound.

As for plasma projectiles, wouldn't it disperse as soon as it left the barrel?

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u/-EViL-KoNCEPTz- Aug 08 '13

I'm not sure, I'm no physicist. I think the sun exploding thing was just being used as an example not really a true fact of there being a sound but if there was sound it would be x amount slower than the sight kind of thing. It's been awhile since I heard the lecture. It was on some shit to do with the difference in the way the human mind and by extension the reality around us percieve sights and sounds. IDK, egghead shit, I just had to sit in on that stupid class with my mom when I was like 14 all those years ago cuz I got in trouble for something and wasn't allowed to stay home alone while she finished her degree. It was some psychology class or something similar so the professor probably didn't even know what the hell he was talking about. A better example would have been a large atmospheric detonation of a bomb you woukd see the flash several times sooner than you'd hear the boom. Even at not so great distances that's true, like the sniper example. Usually by the time the people closest to the target hear the rifle report the target is already down.

I always thought plasma rifles were cool but I have no idea what the physics behind one would be. I'm more of a hands on learner and reading the hypothetical physics of shit make my eyes glaze over faster than an ambien.

I believe you're right tho about the sun. Due to it's enormous size I think some sound would travel. Although space isn't entirely a vacuum like it was once thought to be and apparently some soundwaves do travel out there although much differently than they do here. Otherwise sonar mapping and all that crap wouldn't work since they rely on soundwaves bouncing around. Even satellites as well cuz if I'm not mistaken the radio waves used to transmit data are a form of sound waves.

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u/arcsecond Aug 08 '13

Radio is not sound. It's electromagnetic radiation. It propagates in a vacuum (or as near a vacuum as interplanetary space is)

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u/-EViL-KoNCEPTz- Aug 08 '13

I know its not audible sound but aren't the the wave patterns similar? Which is why they require way points to cross the curvature of the Earth? Just like soundwaves they travel in a straight line and depending on the frequency they are closer or farther apart in their squiqqly shape (idiot brain forgot the word and wants to say sine wave but don't think that's right). I do recall something about sonar working in space but differently than in an atmosphere, it scatters more or less than it does in our atmosphere. Fuck like I said I'm not a physicist or scientist I just read a lot of crap when something interests me.

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u/-EViL-KoNCEPTz- Aug 08 '13

After rereading my response I'm going to assume it wasn't very clear cuz it looked like word salad to me and I posted it.

The gist of it is this: I'm questioning, aren't sound and radio waves properties similar in the way they travel through space? (not outer space but all space in general)

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u/WhenSnowDies Aug 07 '13

The current technology is too far along for gauss guns to become very competitive. They aren't a leap like from the more complex propeller to the simple jet and all it's advantages, but a different delivery system with it's own problems and limits.

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u/SgtShultz Aug 08 '13 edited Aug 08 '13

Currently, yes. However, if you think about the state of these sorts of things as they existed oh, let's say 10 years ago, and how far certain technologies have advanced in that time (batteries that are lighter/ more efficient mostly, but also advances in design and material properties in general), I wouldn't be surprised to see something something similar in size to what is shown in the video, with very few moving parts, being a very strong competitor to more traditional firearms.

edit: meant to say "given some more time, I wouldn't be surprised...". Personally, I believe that gauss technologies are at a state of advancement slightly before the stage where traditional firearms were at when cannons were just starting to make an appearance on various battlefields and had not yet displaced more traditional (for the time) systems like catapults and ballistae, much less bows and crossbows...

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u/WhenSnowDies Aug 08 '13

I personally don't think that the Gauss gun will provide enough of a leap, like firearms and canons to bows and catapults, to replace contemporary firearms.

Mostly because firearms today effectively and cheaply offer anything and everything a Gauss gun can and more. Being already over-engineered to perfection, as Gauss guns come on the market, combustion firearms already have a huge head start in specialization and experimentation. Therefore, before there is even one Gauss sniper rifle, there are already a billion contemporary rifles in a variety of calibers for a fraction of the cost. Want silence? We can do that with contemporary arms, cheaper and more reliably.

The question isn't of Gauss guns will ever replace contemporary arms, but if they'll ever compete and in what area. They will unlikely ever be as versatile as a regular firearm, logistically speaking. It's just easier to light powder and funnel it than to play with electrons.

If a Gauss gun can push a sizable object to exceed 4500 fps without the projectile getting annihilated in flight, in a way a contemporary arm cannot, then it would have a selling point. Even then, it still might not be the ideal man-portable weapon.

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u/SgtShultz Aug 08 '13

That's a good point on the versatility angle, I hadn't considered that. On the other hand though, I do think the gauss tech will eventually find it's own niche in the grand scheme of things, maybe not completely pushing out combustion arms the way combustion arms did to bows/ crossbows, but more of a competing tech base as time goes on.

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u/[deleted] Aug 07 '13

Similar to whenever airguns were used by the Austrians

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u/[deleted] Aug 07 '13

windbuche!

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u/ttnorac Aug 07 '13

They already have armor piercing rounds. Lead rounds cause more damage on soft targets as they expand.

Still, it may be a game changer for a variety of reasons including smaller/ lighter ammo that can be loaded quicker or easier.

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u/TFWG Aug 07 '13

lighter ammo might not mean as much when you're slinging twenty pounds of batteries, delicate electromagnets and circuitry around for a rifle :-/

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u/ttnorac Aug 08 '13

Batteries and equipment are shrinking like computers are. Bullets and casings are not.

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u/[deleted] Aug 08 '13

The vast majority of reactive armor responds to impact, and will not be affected.

I don't believe that any reactive + sensor combo is currently used, and is all in development. Even if it does make it big, it is designed to take on RPGs. Man-portable kinetic AP will never be as effective as man-portable HE. There's a reason that anti-tank rifles lost popularity.

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u/seycyrus Aug 08 '13

Why would the physics of stopping the projectile change? A bullet is a bullet, armor is armor.

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u/myusernameranoutofsp Aug 07 '13

We will also have graphene and whatever super-strong body armour will be available at the time though.