My wife requested to go along with me for this weekend's caribou trip and is wanting to try to take the animal. All I have that she can handle is my Thompson/Center in .223. I know lots of people say 243 and 223 can kill bou but I just don't trust little calibers yet. I'm thinking neck shot, but have never myself tried a neck shot. Opinions? Experiences? Advice? Does it kill the animal as reliably?