"But when a strange dog meanders into my yard and doesnt leave and acts like he wants to bite, I wont hesitate for a minute to pelt him with a BB gun."
I've heard that spraying a dog with a water hose gets them to go away.
Surely there are other ways besides having to shoot them. Try a fog horn, anything....
Wash out an empty soda can. Insert two pennies. Tape the mouth closed. Voila - instant anti-canine noisemaker. Works on every dog, guaranteed.