Games - Looking for Sniper! or Bug-Hunter!

In my research on Rebelstar for OVS4, I've been trying to do some digging on the Sniper! game that Julian Gollop quotes as being an influence. I'm currently trying to get a cheap copy of Sniper! and Bug-Hunter, both produced by TSR in the mid-late eighties. The game first game out in 1973 by SPI and was a turn-based combat game. I'm looking for the later revised TSR version (though would be very keen to see an early SPI one) and even though Bug-Hunter was post-Rebelstar, I'm interested in it mainly because of it's Science Fiction setting.

If anyone could help, I'd be very grateful. I'm also looking for a game called Snapshot by GDW.