By some of the thought processes here we should all go back to the 30 cal carbine, 30/30 or 6mm, they've all taken deer and at one time were considered the most you needed to carry. And they kicked a lot less than the 270 or any magnum. They all have a place, we all have our favorites, and some folks still like hunting with their old favorite. Places like IL you don't have the choice it's a matter of 12 or 20 gauge? And a 1 oz slug at up to 1900fps from a 3" shell kicks like a mule (although I've never actually been kicked by a mule...) We can probably reach contested agreement that by today's standards the .243 or 6mm remington are about as low as you want to go on the energy scale for small to medium sized whitetail inside 150 yards, but the top end??? I know a 385 grain sabot from a 12 gauge will literally scramble the heart and lungs of a deer at 40 yards and blow through the shoulder bone and still keep moving definitely more firepower than I needed, but it's what I had in my hand at the time. And the quick work it made of the first deer allowed me to take the second before it knew what was going on. Overkill is only overkill if you spoil extra meat. As long as you're comfortable shooting it, take the gun you like.
Helicopter Bill