I need to build a completely horizontal projectile launcher for my physics class. I started experimenting with a Gauss rifle, but the horizontal velocity was hardly even 1m/s, even with strong magnets. I'm looking into a few other propulsion mechanisms, such as pressurized air (like a spud gun) or some sort of spring/rubber band driven crossbow, but I was trying to see if I could get any more suggestions or tutorials on projectile launchers. The projectile can really be anything, but something along the lines of a steel ball bearing would be ideal. And no, I'd rather not take the risks of building a coilgun ;P Thanks for the help!