I have had nothing, but good luck, with the 180 grain failsafes in deer. I couldn't tell you much about expansion on weight retention because I have never gotten one back. All have gone completely through. That includes a shot last December from throat to bung hole. I couldn't imagine a better bullet for moose if you're using the 30-06. I have never had a deer go more than about 40 yards after taking one of those in the boiler room, and most deer just drop and quiver.