If you’re new to shooting, you might have questions about terms used to describe trigger operation on handguns. We’ll clear up one of those terms here.
What Are Double-Action Only Triggers?
A DAO (Double-Action Only) trigger is a type of trigger found on some revolvers and some semi-automatic pistols. A DOA trigger requires the user to press a long DA or Double Action trigger pull to fire the pistol or revolver for each shot. On pressing the DAO trigger the trigger cocks the hammer or striker and fires the pistol.
The DAO trigger, as the name suggests, can only operate in Double Action. At one time may Law Enforcement agencies in the US and around the world equipped their agencies with DAO pistols and revolvers. The theory behind a DAO trigger is to provide more trigger resistance so shot are fired intentionally and not by accident or unintentionally. For this reason some EDC (Every Day Carry) revolvers and pistols use a DAO trigger. Since the DAO trigger requires more deliberate effort to fire the pistol or revolver it is considered an added layer of safety.
What Are DAO Revolvers?
A DAO revolver is typically used for self defense and concealed carry. Examples of DAO revolvers are the Ruger LCR and Smith & Wesson Model 442. These are short barrel or snub-nose revolvers designed for EDC. These revolvers have internal hammers so rear portion of the revolver is hammerless, meaning there is no external hammer to cock the revolver and shoot it in SA or Single Action mode and there is no external hammer to snag on clothing when drawing the revolver. The DAO trigger on these types of revolvers requires the user to press a long double action pull to deliberately fire the revolver.
What Are DAO Pistols?
A DAO pistol is a semi-automatic pistol that can only fires with a long double action trigger press. There are both hammer-fire DAO pistols and striker-fire DAO pistols. Some examples of DAO hammer-fired pistols are the Smith & Wesson Model 5946 and SIG P226 DAO. Both of these pistols are hammer fired and the hammer is bobbed, meaning there is no hammer spur to allow the user to cock back the hammer. This requires long, double action press of the trigger to cock the hammer and fire the pistol. Even after the slide cycles after the shot, the trigger stays in DAO mode. Striker-fire pistols are also DAO pistols. An example of a DAO striker fire pistol is any Glock pistol. With a striker-fire DAO pistol, the trigger has a long pull. As the trigger is pulled in a Glock striker-fire pistol the striker spring is pulled rearward and then release the striker to fire the pistol. When the pistol cycles after the shot the trigger stays in the same DAO mode.
While a DAO trigger takes more effort to fire, the design of the DAO triggers in revolvers and pistols enables users to easily conceal carry these revolvers. Since DAO pistols and DAO revolvers require a heavy trigger pull, they are most used by Law Enforcement and by many who concealed carry a gun.
Article by Gun Tests Contributing Editor Robert Sadowski. Images courtesy of the manufacturers.
