The DIY portable 1.25 Kilojule Coilgun took YouTube user Larsplatoon two years to make, and as you can see from the photo below, it looks like a serious bit of kit.
It packs a 12 volt high drain battery, four large capacitor housings in the stock, and a charging circuit in the foregrip, you can see it in action in the video below.
As you can see from the video it looks pretty impressive, and seems to do a fair bit of damage to anything it is fired at.