Can you kill a man in NH for trying to break into your home?

[d from birmingham]

In still other places you hafta be running away from the perp to
legally shoot back (the retreat law) -- I haven't figured that one
out yet (how do you outrun a bullet??).

That is not what the law requires. The law states that if you can get away safely say drive away from the area where the bad person is, without being harmed then you have to do so. Otherwise you have to state why you didn't retreat. For example if I am walking home from the store to my house and a mugger approaches me with a knife I would state I couldn't retreat because the mugger was within a foot of me when displaying the knife and he threatened to stab me. So I pulled out my gun and shot him because I thought he would stab me if I had tried to run away. That is what duty to retreat means that you have to reasonably explain your actions and why you couldn't act in a non violent way.

It is to help police determine if you were the one who actually started the incident. Because you have to explain what happened. Often a number of self defense incidents are not self defense but the result of one person getting into a fight with another person and then the loser pulling out a weapon and killing the other person then claiming self defense.

[Nonesuch]

Luckily there is no duty to retreat in NH as long as you were not the initial aggressor, so no need to be concerned about circumstances like this as long as you don't start the fight.

I don't think "duty to retreat" is about helping the police, it's more like OSHA for muggers.