David Douglass The answer to your question lies in one factor---the unpredictability of reality. So...you fire your pistol into what you...at the time of stress...believe is a safe sensible place or area. However there was something hard enough there, to cause the bullet to skip and continue downrange to.....something you never intended it to travel. Someone else could be struck or you could get lucky.
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You could also encounter a misfire, experience a jammed case, rendering your pistol inoperable. In which case the threat then...full of rage....attacks you, takes away your gun and ...who knows...the battle is on.
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Or you could fire the round into the earth successfully and the threat has enough time to rush you.
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Have you ever tried having someone rush you from 20 feet away in order to determine how much time it takes to physically take you down? And you should be made aware that, shooting WHILE an 'armed threat' is more than 22 feet away completely removes the essential element of "Imminent Threat'" which you will need to accomplish a legal credible self defense claim.
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Your comparison is flawed in that....a verbal warning or command is NOT the equivalent to shooting a deadly weapon in order to determine true intent of the attacker in the eyes of law enforcement or the rest of the legal system.
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Your threat could pin his word against your word, that he didn't really physically threaten you, but instead was just angry and it was YOU who brandished a weapon, fired it into the ground, and threaten him, just for being angry with you for what ever reason.
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You would lose another element of a legal self defense claim, which is "Innocents" by attempting to scare or ward off the person whom you believe was a threat with brandishing and discharging a firearm BEFORE you were attacked--which ironically....proves you were not truly experiencing an Imminent Threat.
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Your case for a legal self defense claim is therefore non-existent. You go to jail.