I recently read an article on this subject (I don't remember the publication or the name of the article), but in summary, the author determined that all else being equal, there is quite a bit more potential for something to go wrong when using a semi-auto than with a revolver. Things such as magazines not properly locking when inserted in the gun - and subsequently falling out and the limp wrist semi-auto misfire. Also, if a light primer strike should occur, with an auto, you need to manually cycle a new round into the chamber. With a revolver, you simply need pull the trigger again and the gun does the rest.