Lasers are actually pretty terrible weapons for individuals. They require too much energy to really do enough damage. To get a powerful enough energy source you'd need a vehicle, and a really big one, too.
A lot. Other cool stuff: View: https://www.youtube.com/watch?v=dvrQciFL0ig View: https://www.youtube.com/watch?v=vAs9EHtKfVc Not homemade: View: https://www.youtube.com/watch?v=fNLrQhn5nLo Generally... View: https://www.youtube.com/watch?v=1hsDn2kNriI Yeah, we're not really a "sane" species, us humans.
Dunno. I know they're mounting it on some sort of destroyer or cruiser or something. Modern naval warfare may not require a large number of guns though.
Here's another video about the railgun. View: https://www.youtube.com/watch?v=eObepuHvYAw Its projectiles travel at Mach 7.
