My husband apparently made such a thing when he was in school, for a science fair project. I suspect it was designed so it wouldn't damage anything seriously. He's a bit bitter about it, something to do with the science teacher not appreciating how much physics was involved. I dunno, you'd have to ask him.

As for propelling objects into space...The escape speed (the speed an object needs to be going to get into orbit) is 11 km/s = 7 mi/s = 40 000 km/h = 25 000 mi/h. It might be tricky to get something moving that fast with a rail gun. Not sure of all the subtleties there, though.