Ask Tony Martin how that worked for him. He shot punks that had robbed him 3 times and got hard time.
He was recently denied parole for fear that he might still pose a threat to burglars.
And yes, he's been sued by the crooks.
http://news.bbc.co.uk/1/hi/uk/717511.stm
http://www.guardian.co.uk/martin/0,2759,214318,00.html