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# kinetic energy gun

Like the trick with the basketball and the golfball.
 (0) [vote for, against]

When a heavy mass hits a lighter mass in an elastic collision, the lighter mass ends up going faster than the heavy mass was. The KEG (Kinetic Energy (concentrator) Gun) uses this fact to give great speed to a small mass.

The Keg uses rubber bands/pneumatic pistons/springs to accelerate a (probably) metal mass to a low speed. This mass then collides with a stack of masses. A steel projectile is held magnetically to the last part (dimple in last part, magnet-ring behind that).

The Keg’s near-muzzle parts would have to be made of something very hard. Tungsten, titanium, or molybendeum might work. A keg would have smaller ammo than a normal gun.

 — my-nep, Nov 25 2003

How and Why is DU used? http://deploymentli...u_library/how.shtml
(First off the Google rack.) [Detly, Oct 05 2004, last modified Oct 21 2004]

'Safe' Alternative to Depleted Uranium Revealed http://www.mindfull...en-Alloy30jul03.htm
[Detly, Oct 05 2004, last modified Oct 21 2004]

Just slightly off topic, I've seen Railgun projects by various groups of college students ... some were relatively successful
 — Letsbuildafort, Nov 25 2003

Back to the idea. [my-nep], bullets are actually designed to do the opposite of this. The reason lead is used is because it's heavy. You can put more energy in a heavy object than a light object going a given speed. Why slow and heavy is desirable is so that the forces that the air exerts on the bullet are small. If you have a very fast object you'll get more air resistance. If you have a lighter object you'll have less accuracy. Combining the two makes for inefficient ballistics.
 — Worldgineer, Nov 25 2003

 {elastic collision]

 some sort of underwear accident?

 [ The Keg’s near-muzzle parts ]

I think I was at a party like this once - we never did get our deposit back from the liquor store
 — normzone, Nov 25 2003

 [UnaBubba] - interesting you should bring up hardness. Depleted uranium is used to tip ammunition for two reasons: (1) It's friggin dense (about twice as dense as lead) (2) It displays the rather bizarre property of self sharpening - that is, as it travels through the air or armor, the tip will become sharper, not blunter. I'll see if I can find a reference for (2).

By the way, it's not just the bullet that causes the damage, it's also the tiny shockwave that builds up in front of it. If you're shot in a vacuum, it should (probably) appear a cleaner shot (but you might be distracted by your body exploding, or, if you're firing, you may be rather frustrated at the combustion not taking place).
 — Detly, Nov 25 2003

 UnaBubba, sorry I thought molybdeum was a very hard alloy. Ok, so none of that stuff in the KEG.

 Worldngineer, I did not mean lighter PROJECTILES I ment lighter SHELLS ( shells contain powder, casing, bullet )

 Regarding the rifling, a short rifled barrel can be added to the end

normzone, an elastic collision is a collision where energy is not lost in damaging the parts ( or generating heat ) example: bouncy balls. An inelastic colision is where the parst are dammaged/generate heat example: Cars.
 — my-nep, Nov 29 2003

"Tungsten shells flatten on impact, forming a mushroom shape. But DU rounds self-sharpen as they deform because material breaks away in a way that preserves the shell's shape, a phenomenon known as 'adiabatic shear banding'. DU rounds are also pyrophoric—the fragments ignite in air, torching the interior of the target vehicle." (see link #2)
 — Detly, Nov 30 2003

[UnoBubba] - You raise an interesting question. The triangular structure of tri-nitro toluene is very, very unstable, so I wouldn't be surprised to find that an explosion could occur, even in the absence of oxygen. However, the linear "released" form of TNT would still need something to combine with to account for the extra orbitals, and in the absence of oxygen, it would have to settle for either the metal in the cartridge, other molecules of TNT, or whatever else goes into black powder. I'm not sure that there's an oxidizing agent present. You might get an inefficient explosion, and whatever managed to react would leave a terrible residue. At least, that's how it looks to me.
 — Overpanic, Dec 01 2003

 //the lighter mass ends up going faster than the heavy mass was//

 //I did not mean lighter PROJECTILES I ment lighter SHELLS //

I must not be understanding your invention. I assumed the point was to use a heavy mass to strike a lighter mass, the lighter mass being a bullet. Are you saying the lighter mass is a bullet with shell, and fires in the usual way? If so, this is very interesting. This would result in a longer force on the person firing the gun, which could provide more velocity to the bullet but would also allow more time to move the gun out of position before the bullet exits. Although this may rule it out as a hand-fired weapon, it may work well for stationary weapons.
 — Worldgineer, Dec 01 2003

 No, there are no explosive. Lethal. ( possibly ) Yes. (guns already wheigh 9 lbs. though, so not to much more)

<world engeineer's original thoughts where correct - although there are medium-wheighted mediators.>
 — my-nep, Dec 03 2003

 Because people are having a hard time understanding I'll try one of those word pictures...

 (00)-----(0)()0o.=

 The large mass (left -> (00) ) is propeled towards the smaller masses (right) (in this case by a rubber band -> --). The period is the bullet, the =is the barrel. Again,

(00) = Heavy Mass (impactor) --- = rubberband (0) = heavy mass () = weighty mass 0 = medium mass o = light mass . = bullet "=" = barrel
 — my-nep, Jan 02 2004

I don't see how this is an imporvement over a crossbow. You're adding a lot of mass and inefficiency for no extra benefit.
 — Worldgineer, Jan 02 2004

You find a cross bow that shoots expendeble ammo at more than 350 feet/second!
 — my-nep, Jan 06 2004

But how is that an advantage? Your 350 feet/second ammo will have to be very light. Very light, quick moving projectiles slow down very quickly due to air resistance compared to heavy, slow projectiles.
 — Worldgineer, Jan 06 2004

 Have problem? go to where the problem dose not apply...can you apply that to your question?

*anshishication*
 — my-nep, Jan 08 2004

 To all those debating whether a gun could be fired in a vacuum: from experience, cordite will ignite just about anywhere (in an argon chamber, underwater, etc) and so would probably go off in a vacuum if it were at ~20 degrees C.

You could fire a gun in space, if you were in the sun: however, a 30.06 would end up pushing you backwards at about 5m/sec. Probbaly not the greatest thing.
 — Macwarrior, May 04 2004

I suppose that a gun would have to fire in opposite directions at once, in space. Then the gun itself would not move.
 — Ling, May 05 2004

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