Ever since I was a little kid, I have only dreamed about harvesting all 28 species for the Grandslam. I have my bow ready but I need to get a rifle. What is a good sized caliber for moose, bear, pronghorn, deer, etc. I need to know because I have decided to just take a break and try shooting all 28 Grandslam species. Do you think a .30-06 or a .270 would work well. Please reply. Thanx!