Justifiable us of deadly force is allowed when the person is, preventing great bodily harm to themselves or others, a murder, or a felony. In these cases there is no duty to retreat. Firearms may also be used in the lawful keeping of the peace, or lawful suppression of a riot
Castle Laws are laws that address the use of force when defending one's self inside their home, or on their property. Some states expand this to vehicles, and the person's place of work. Castle Laws generally include: the places where this law applies, the requirements fro use of deadly force, if there is a duty to retreat, the amount of force that maybe used in defending one's self or others. These vary widely from state to state.