With some practice, one can learn to pull the trigger fast as heck...
I credit having played video games since the 1970's for my fast target-aquisition and firing skillls
If you have a Wii, go get Link's Crossbow Trainer...within a few weeks of daily play you'll be smokin' fast!!
If you think Video games are just for kids...think again...
Or if you just can't get into the game thing...watch vids of Jerry Miculek over & over & over again...
and practice (dry-fire with snap caps) while you watch...it will help.
And the next-to-last helper...get a Calico pistol or carbine...100-rds per mag of 9mm or .22lr or .40 S&W fun!!
Finally...there is THIS!! Guaranteed to bring your finger strength/flexibility/speed UP!!
Which you need to be faster than average...yeah, finger exercises...you DO wanna be as fast as Jerry M., right?