Forget lasers, plasma blasters and lightsabers. When it comes to turning the other guy to dog-meat, nothing beats the pure kinetic kill of a gun. Modern firearms are so effective that they haven't strayed far from their late-medieval-period roots. This 1.25Kj coilgun changes all that. It's an effort to put the science back in slaughter.
The coilgun forgoes gunpowder in favor of electromagnetic energy. The four large capacitors draw power from the 12V high drain battery. Once the capacitors are fully charged, a LED on the front sight goes green, and it's ready to fire. Squeezing the trigger releases all that stored energy into the 10 gauge magnetic coil, generating the 1.25Kj needed to launch the projectiles at speed.
Do-it-Yourselfer Jason spent about two years of his free time crafting the gun from cellphone parts and other electronic recyclables. It's also far from being a manstopper at this stage. The 3% efficiency means that only 37 joules of stopping power make it to the target. That's not enough for a ranged kill, but might have a better chance point blank. I guess you can still keep it handy...for close encounters.
[source: Popular Science]