Someone created portable working railgun that shoots metal and carbon projectiles. The railgun uses 6 300J, 350V, 5500uF capacitors which combined weigh 20lbs and can deliver >1050V and 1.8kJ of energy to the projectile. Most of the structural parts are 3d printed. The gun is huge but it works.
Here is video of it firing (bad word) a small carbon cylinder. The power is simillar to an airgun pellet.
It is an impressive engineering and design project but it doesnt have any real.-world applications :-) Yet.
Full photo gallery with all the parts:
Reddit thread about it:
Interview with the creator: