While some railgun projects are attempting to be the biggest and baddest, this one just wants to be functional. It’s not efficient or powerful, but it is really easy to put together. The barrel is constructed from two 3″ long pieces of aluminum weld bar with heavy duty Lucite sandwiched in between. The gap is only 1/16″. A disposable camera charging circuit plus 4 capacitors salvaged from other cameras provide the power supply. The projectile is a tiny piece of aluminum foil. It may not be the greatest gun ever made, but it looks like it would definitely be a good demo unit. Here is a coral cache of the site.