"Danger! High Voltage. Do Not Touch. Death or Serious Injury May Occur," reads the yellow sticker on the side of this 1.25 Kilojoule DIY coilgun. Watching this video of it in action, that sounds about right:
The battery-powered projectile-blaster took 2 years to complete, according to its creator, YouTube user Larsplatoon, and it packs four capacitor housings, a 12-volt high drain battery, and an old cell phone regulator board to keep it from overcharging.
Larsplatoon dubs it a "1.25kJ Coilgun"—that's some 78 times the amount of energy lethal to human beings—though Make points out that that's likely the capacitor's theoretical maximum output. By their calculations, 1.25kJ of muzzle energy would give the coilgun more oomph than a .45, and while it certainly has no problem tearing through those glasses, it's not exactly shattering them into a million pieces.