[308Enfield]

+1 KC135. I'll add that in any and all of those scenarios there is the question of what's behind your target, what happens to your bullets if you fire, and the fact that once you bring a weapon into play you've raised the stakes for yourself and everybody else. Every situation is obviously unique, but hard and fast rules that you WILL engage people who are doing anything threatening is a bad idea unless you're a LEO.