Single Action Only (SAO)

The term SAO is an acronym that describes a handgun operating method called “single-action-only.” This means that the firearm—typically a handgun—has a trigger that executes only the function of dropping the hammer to fire a projectile. An example of an SAO firearm is the 1911. The hammer must be cocked back manually before the first shot rather than the trigger cocking the hammer before the first shot as on double-action pistols.