What do you want to hunt? Michigan only allows center fire in the northern half or above Cadillac. We have three zones. I believe the smallest caliber for deer is 243? I know lots of people have used much smaller but lets be humane.
You can hunt deer with a high powered rifle in Kentucky, I live in Indiana but not by much, I have co-workers and friends that live in Kentucky and hunt deer with SKS's, Mosin-Nagants, 30-30, .308 and some others.