You picked the right state, Wyo has both a lot of prarie goats and some big ones. There is a lot of public BLM land that is kinda checker boarded across the state that has good antelope hunting. You can get maps that show you exactly how the blm land lays. I've shot lopers by Gillette and Saratoga but there is a lot of antelope everywhere. I've gotten them with rifle and blackpowder. shots range from 100-300yds. They are not to hard to bring down any mid-range caliber would work fine.