I'm looking for my first handgun. I understand SA and DA; and DAO in theory but not as it's been shown to me in practice on several semi-auto handguns. To me Double-Action-Only should mean cocking the gun only loads a round into the chamber, but does not set the fireing-pin. Pulling the trigger each time should first set-the fireing-pin and then release it, fireing the round. I've seen alot of hammerless guns like the "S&W Sigma Series" which are labeled DAO. When I was shown this gun in the store, one had to first cock the gun to set the firing-pin before pulling the trigger which only released the firing pin. (sounds like SA to me). My biggest concern with this setup is this: Since there is no hammer, I asked how does one disarm the cocked "ready to fire" weapon, if you decide not to shoot someone. The guy showed me you had to first remove the magazine, clear the chamber, and then dry-fire it to release the pin. This doesn't seem very practical to me at all. What am I missing?