For average deer sized animals I think you should shoot whatever ammo gives you the best groups. When I hunted Colorado for elk my back-up rifle was in 270 win cal. I used Remington safari grade ammo loaded with Swift-A-Frames in 140 gr. I sighted in zero at 200 yds with 2" groups about the best I can do. 130, 140, 150 gr, probably won't matter much on deer even mulies. If I was going after 250-300 lb bucks I'd probably shoot the 140 or 150 gr in a premium factory load which are easy to locate but a bit expensive, however, cheap compared to the overall hunting trip cost.