Are we hunting to survive? or hunting for the personal challenge and satisfaction of a hard job, well done?
For survival, a 12 ga and a variety of loads would probably be the most useful choice.
For the satisfaction and challenge variety, grizzly with a slingshot.
Just personal preference? Any accurate rifle. I'm partial to squirrels with a rimfire.
I was thinking a heavy free floating barrel.308 with a high power scope. But on second thought I think I would want a light weight ar .223 with 1/7 twist and a scope.