Put his gun through a table saw. Then tell him to deal with it becuase his shooting of other people is a worse act than vandalizing a $15 clearsoft pistol.
Hide your gear and tell everyone else to do that same so that he can't find them.
If he comes back with another one, take it and hide it. Or for each time he shoots you with it, have everyone shoot him back with one.
An eye for an eye, a tooth for a tooth, and 100 shots for every shot fired.
Ares M110 LEAF - Ares Striker Tan
TM G17 Pink - KJW P226 TwoTone