

The Physics of the Railgun - ChrisAntaki
http://www.wired.com/2014/08/the-physics-of-the-railgun/

======
madaxe_again
Railguns are fun to build as a hobby project. All you need are a pair of
rails, and a conductive slug. Ball bearings work well.

The tricky bit is reducing arcing between the rails and the slug, as you can
end up with it either welding onto the rails, or carbonising and ending up
with "dead patches", sapping your power. Main trick was to go for gobs of
current with as low a voltage as we could manage.

We used big capacitors re-purposed from a tesla coil (cider jars!), and copper
plumbing pipe filled with gravity-fed circulating mineral oil to keep the
temperature manageable.

Think it was 1.5m long or so, and we were using a 10mm ball bearing... and it
happily disappeared deep into a brick wall never to be seen again.

Fun times, but lethal if you're not careful.

------
daveslash
It would not surprise me if, given time, we see smaller versions of these
being produced for individuals. Given the controversy over gun-control (what
exactly _defines_ a gun?), I wonder how this will play out. In this comment, I
take no side in the gun-control discussion; I'm curious how the national
discussion will change.

Edit: This is in the context of U.S. gun control discussion.

~~~
trhway
airguns can be pretty powerful too. In Russia, for example, the law limits the
muzzle velocity and kinetic energy of projectile. The laser guns is different
issue though :) And there is also various nonlethal weaponry like 96GHz
directed energy devices
([http://en.wikipedia.org/wiki/Active_Denial_System](http://en.wikipedia.org/wiki/Active_Denial_System))
which i suppose will get to be miniaturized soon.

