Pulser

this one falls more into the realm of scifi but depending on what the future holds, might actually be a practical tool, a crude experimental barrel attachment for a ruger 10/22 that when properly constructed, will strip some mechanical energy from the bullet transducing it to an electromagnetic pulse with each bullet fired, it is basically a coil form with the intent on wrapping copper wire around it, 2 internal holes act as a switch by feeding 2 small metal contact points into(bare wire).
in theory, a high voltage capacitor is charged(say 1350v), the bullet is fired which when it enters the coil form makes contact with 2 terminals completing the circuit, a surge of electricity energizes the coil momentarily which will create a magnetic field around the coil, the bullet passes through the center of the helical coil which warps the magnetic field due to the diamagnetic nature of lead which the bullet is made from(when moving through the magnetic moment, a diamagnetic metal will generate its own counter magnetic field), this process creates a magnetic flux compression/expansion effect lasting only a split second. in the process, mechnical energy is stripped from the projectile and in part converted to a magnetic pulse.
the end result is a slower moving bullet accompanied by a small EMP, a reloadable and reusable version of an explosively pumped electromagnetic flux compression generator.

there will be no schematics for this and no instructions on how to complete the build, if you have no idea what this is, stop right there and build something else.