I did a black bear hunt for my 50th birthday as well. I chose New Mexico because of its proximity, but any of the locations suggested above would work. I also recommend spot and stalk — I was clear with my outfitter that I didn’t want to hunt over bait and especially did not want to hunt with dogs.
I used a .30-06 with 180-grain bonded bullets that my outfitter recommended. He wanted to ensure good penetration if I hit a shoulder, which I did. I took my shot from about 150 yards but we encountered bears we couldn’t shoot (sows with cubs) much closer than that, and I would have been nervous with anything under the .30 calibers.
