Both weapons are great for deer hunting. Quite often I bring both a rifle and a shotgun out for a days hunt. I watch a field real early with a rifle. Then I get out the shotgun and head into the woods.
Jon-M, Have you tried lighter bullets in 458 for even more velocity with less penetration? I agree that there might be a rifling twist/keyhole issue out past 150 yards or so, but I am thinking that under 100 yards Bambi won't have time to notice a bullet instability.
For you slug throwers give something from Dupleks a try. One of our guys use one last years at 180yards and he said it hit like no slug he had seen before. They have several types of slug . This one throws of the peddles, another one keeps them intact. I will use these one next slug gun season but will stay with my 308 during rifle season. I am use to shooting thru small holes between branchs at distance in the bottoms with it wher you can hear a deer before you see it. Most times if a guy has bad luck with bullet perfroming well on game its ether wrong bullet for the job or bad bullet placement not the size of it.
Let me tell you,a 12 gauge slug at 25 yards will knock the snot out of a deer and drop it right there,but with a rifle you tend to get better accuracy because you're not gonna flinch on a .270,30-30 etc,and your shot placement will be much better.