I would use the .270 unless you are expecting shots over 400 yards. And if so can you hit the vitals on a deer past that range every time? Not saying you can't, just asking. Don't really see the need for a cartrige like the STW unless hunting pronghorns or planes deer, even then the .270 will still reach out there far enough. For deer size game I would use the Nosler BT 140gr or 130gr schrocco.