I KNOW I couldn't hit a black bear where he lives at 600 yards, so I would never try. I even personally know one, or possibly two individuals who probably could hit a wee black bear where he lives at that range, but I am pretty sure they would never try it. I say probably, because I have never had the opportunity to set up a volleyball sized target, obscured in shape and form, at 600 yards range, and they challenged either of them to a one shot hit. Known range, (we acknowledge good laser range finders) unfamiliar terrain, any position, but realistic terrain, target and shooter will be in wild lands.
Don't think either of them would bet their gear on the shot! Oh, I know folks make those shots every day, and snipers make lots of hits at twice that. Making the shot, or getting a hit at an enemy, is not the same as an ethical hunting shot at an animal which may become dangerous to others if wounded. Feel free to get after it. And to jump down my throat 'cause you do it every day.