Tippys are designed
to get wet, and beaten. The only thing you will notice is the screws that hold the 2 body halves go rusty, but they all do anyway. Dont use WD40 on the tippy, as it kills the o-rings (so they say at tippmann) but just get some good make light oil, and squirt it in the rear slot, and chamber. All will be well.
(I would recommed stripping it once in a while, as crud gets in through the back cocking slot, and can play hell , jams etc.