Trope-a-Day: Magnetic Weapons

Magnetic Weapons: Almost all of them, in fact. Happiness is a warm coilgun1. (And a plentiful supply of exchangeable heat sinks, because even fancy superconducting orichalcium coils3 can’t stop the Second Law.)

Handgun versions fire super-tiny flechette projectiles at mind-croggling speeds, because, well, like the picture implies…


…it ain’t the mass, it’s the kinetic energy. And since E = 1/2 mv2, they know which variable to concentrate on. Vehicle-mounted and starship versions fire, ah, rather bigger but still uncannily small projectiles at similarly mind-croggling speeds.

These projectiles, incidentally – with the exception of various sluggun esoterica most of which are deliberately slow-fired and intended for purposes not involving doing gross damage – are by and large not fitted with any kind of warhead. Pump enough KE into your k-slug, per Rick Robinson’s First Law, and fitting a warhead to it as well is just gilding the lily.

(Also, not fitting warheads to your most common type of ammunition has the advantage that your magazines stop being a one-hit kill. Photon torpedoes, say, would go up like antimatter-stuffed firecrackers in sympathetic detonation. K-slugs… remain solid lumps of metal. I know which one I want to be sitting on in a firefight, and the US Navy appears to agree with me.)


  1. Well, technically, the modern kind also have vector control handwavium in them to get more bang for your buck, but the idea is the important thing.
  2. Not a footnote.
  3. Which are also used in the very-high-energy-density batteries that solved the power problem for portable coilguns.