If you believed the guy's life or yours was in imminent danger, it would be good. If not, it wouldn't. In Michigan, if you shot the guy in the back as he fled after telling him to stop, it would be good, whether the gun was operable or not, because at that point he was a fleeing felon whether the gun was operable or not.

It all depends on how you explained your rationale for shooting the guy and what you inferred based on your perceptions.