I haven't read all 8 pages of this thread, but just a thought in passing from a guy who watches the TV show "Forensic Files" pretty regularly. The ejected empty case from a semi-auto is as distinctive as a finger print to these forensic crime solvers and if a bad guy was intent on committing a crime with a handgun, taking the spent case with them in a revolver would be one less clue that the police had to work with. Not being a bad guy myself, that isn't the reason that most times when I carry it is a J-frame .38 Special only because it is way lighter than any of my semi-autos.
