Double Action
A trigger system where pulling the trigger both cocks and releases the hammer.
Also: DA, double-action only, DAO
On a double-action (DA) firearm, the trigger pull cocks the hammer AND releases it — “double” because the trigger does two jobs. DA pulls are heavier and longer than SA pulls but allow firing without manually cocking. Double-action only (DAO) firearms have no manual cock; every shot is DA.