Buster,
I would suggest looking at a ammunition makers website like Winchester or Hornady and seeing what differences there are in the ballistics of the bullets. Then make a choice. And remember it's not all about the bullet it's about can you put the bullet where it needs to be. I have killed lots of big hogs with a .22-250 and 55 grain varmint loads. Not your typical setup but I have never had to go look for a pig. Also I have been to Alaska numerous times and been within 100 feet of many bears with only a flyrod in my hand. Never felt like I needed a rifle.
Also, before you go there are huge areas of Alaska that are National park lands where firearms can not be possessed. You might also check a road map of Alska. There are surprisingly few roads compared to what you are used to. Hardly any paved.
Good luck
2bit