Originally Posted by austin92
Hope the OP doesn't mind me asking here, trying not to start a new thread and Learn the difference between da, sa, and dao semi autos. Any pointers?
This is all about how the hammer of a gun is cocked.....(whether or not that cocking process is handled mechanically by the gun's trigger mechanism or manually by the shooter's hand):
SA = Single action - In a revolver, this means that the hammer can only be cocked manually by the shooter's hand/thumb. The trigger only servers to fire or release the hammer to fire. Pulling the trigger (with the hammer down) will not cock the hammer. In a semi-auto pistol, this is the same thing for the first round fired. However after the first round fired the action of the slide will push back and re-cock the hammer (but not the trigger - pulling the trigger with the hammer down will not cock the hammer).
DA = Double action - This means that the hammer can be cocked either manually by the shooter's hand OR by the action of pulling the trigger. So when the hammer is down, you can simply pull the trigger and the mechanical action from that will both cock the hammer and release it to fire.
DAO = Double action only - Many small, concealable & hammerless revolvers are of this action type. This means that you can only cock the hammer by the mechanical action of pulling the trigger & firing. The hammer cannot be cocked manually by the shooter's hand (most of these types of guns do not have an external or exposed hammer to cock).
Also think of it this way....
When you pull the trigger to fire the pistol - is the hammer already back (ie...are you pulling the trigger only to release and already cocked hammer)? If so, that is single action or using the trigger as single action.
If you pull the trigger to fire the pistol - is the hammer down and the pulling of the trigger mechanically moves the hammer back to 1st cock and then also release to fire? That is double action.
Hope that helps.....