The quick answer is you never use a gun to settle a dispute. As a general rule, you may use deadly force only when you are in fear of death,or great bodily injury. Check you local and state laws for your area.
The rule I follow is firearms should only be used to protect life, never property.
Perhaps, if I am very lucky, the feeble efforts of my lifetime will someday be noticed, and maybe, in some small way, they will be acknowledged as the greatest works of genius ever created by Man.
- Jack Handey