Most of the time trying to rob a gun shop is not a good career move. Used to have one just down the street from where I now live that had an individual walk in one day, tried to kick the owner's border collie (not a good move in itself), then announced as he displayed his pistol that this was a robbery. As fortune would have it, one of the city's finest was there with the fellow in his sights, the owner had the offender in the sights of his 12-guage, and the gunsmith in the back had him triangulated from the back room. Needless to say, the border collie was ready to perform an impromptu circumcision.
The shop is now gone, with a nail shop in its place.