Random idea - possible ridiculous power / velocity.

[mako]

Something I always wondered about these vacuum-barreled airguns; what happens when the projectile hits normal atmosphere? Deformation? Deflection? Functional decrease in speed?

Just curious.

[jackssmirkingrevenge]

It simply slows down quicker, it's not going to be going at the sort of velocity that results in the superheating you would observe on an object from space entering the Earth's atmosphere.