Guys like Tom Knapp make a pretty good living doing shooting shows. I get the feeling it would be easier to get into any other professional sport than to become a professional shooter.
There are several governing bodies for shooting sports but like rj45 said the only way to be paid to do it is with sponsorship from companies.
"They say you can't use a rifle or shotgun indoors because a bad guy will grab the barrel. Yeah? Well, he better hang on, 'cause I'm gonna light him up and it will definitely be an "E" ticket ride."
"Make (your attacker) advance through a wall of bullets. I may get killed with my own gun, but hes gonna have to beat me to death with it, 'cause it's going to be empty."
Clint Smith, Thunder Ranch