I, personally, would not relish going up against someone in less than perfect lighting when he has a rifle and I only a pistol. I don't think most could guarantee a kill shot before being splattered with .223 rounds. Particularly if his partner might be similarly armed.
The point is that it should be your choice, instead of pre-emptively restricted by the state. That's what Freedom is all about.
Lighting, range, available cover, your skill, and the weapon (bolt-action or semiauto) that the murderer is using, are all considerations that must be weighed before taking defensive action.