what does double-action mean
Double action (DA) refers to any gun which can be cocked and fired by a single pull of the trigger. This term most often refers to handguns (pistols and revolvers), but properly applies to any gun that works the same way. When a double action gun is uncocked and loaded, it may be fired by pulling the trigger. The trigger usually travels a good ways in double action, and during its travel it is cocking the hammer (moving it backwards against spring tension).