I have to agree with 460Kodiak, I visit the Smoky Mountains regularly and the parks are just overrun by tourists. I have seen bears many times there and they are not in the least bit interested in the multitudes of people around them snapping pictures. Last time we were there a bear was spotted about 30-40 yards off a walkway, and a crowd of nearly a dozen people was crashing through the woods towards it, cameras drawn. The bear was less than concerned. I can still picture it clearly, in the lead was a obese, middle aged, woman, in white tennis shoes, grey sweat pants, and some over-sized ill-fitting t-shirt. She was stomping and high stepping through the brush in what I'm sure was the most physical activity she had mustered all year, all the time screaming back to her party "HAAAAAYYY, OH MY GOSH, LOOK AT THE BEAR!!!!" Never had I wished for a bear attack so badly
Alas, the small, uninterested bear disappointed me though, allowing her to within 10-20 feet before wandering back into the woods.
It's not so much the crowds that disgust me, though I try to avoid them like the plague. It's the behavior exhibited by people these days. I'm always surprised whenever in public by the rude, inconsiderate behavior of others. Just don't remember people acting like that growing up.
Oh well, all that to say I guess I think the .500 would be way too much. I'd want something much smaller, lighter, easier to conceal and geared towards 2 legged predator defense. The bears are the least of my worries.
ETA: Kodiak is also correct that the Smokys are THE most visited national park.