Have you ever even touched a real gun, in the real world, in real life?
Go back to your computer strategy games ... let the adults deal with reality.
Yes, I have fired a gun in real life, many times, and I know enough to realise that my aim is a lot worse when under stress. You can train at the range all you want, but how are you supposed to get stress training so that you can hold your nerve whilst shooting? I doubt all store owners are highly-experienced combat veterans used to being under fire.
http://www.freerepublic.com/focus/news/2964522/posts?page=15#15