Trigger Actions for Handguns: Common Types part 2
Double Action (DA)
Double Action means that pulling the trigger causes two actions simultaneously: cocking and releasing the hammer. Double Action triggers allow you to fire the gun whether it is cocked or not. Military, police, and self-defense shooters all find this option attractive. DA triggers do require extra length and weight in order for them to be pulled, however, which some believe to be a disadvantage. Most modern revolvers are called DA in spite of the fact that they can also be fired in single action mode. It is single action when you manually pull back the hammer and then squeeze the trigger. the Colt Python .357 Magnum, Ruger SP101 .357 Magnum, Ruger LCR .38 Special, Ruger Redhawk in .45 auto, and S&W Model 29 .44 Magnum are all examples of DA revolvers. Certain DA pistols can be cocked manually with an external hammer, giving them a SA function. These DA guns are often referred to as DA/SA, because they can be fired in either DA or SA mode, while DAO guns have no accessible hammer to cock. DA triggers are longer and heavier than SAO because they pull back the hammer and release it in one pull.
Double Action Only (DAO)
DAO guns cannot be fired in single action mode because they cannot be cocked manually; trigger manipulation is the only way to cock the hammer and release it. After the shot is fired, the hammer is not automatically cocked. Instead, it goes back to an uncocked position. DAO revolvers appear to be hammerless, so there is no way to cock and fire in single action. This is often called “shrouded” hammer because the hammer is hidden by metal to keep it from catching on clothing when the revolver is drawn. The hammer still functions when the gun is fired from inside clothing, like a coat pocket. Some enclosed hammers can be cocked, but they are difficult to reach with your thumb.
Trigger control is incredibly important with DAO. Because the force and length of the trigger pull is crucial, deviations in trigger control and erratic movements often amplify errors. In order to master accurately firing a DAO firearm, frequent practice is necessary. Although the trigger press among these guns is typically consistent, it’s usually longer and harder than SAO or striker-fired guns. The typical amount of force needed is 5.5-7 pounds for pistols and 8-12 pounds for revolvers. A DAO gun can be either a semi-auto pistol or a revolver. The hammer of DAO pistols will go back and rest behind the slide after each time the gun is fired. The trigger cocks and releases the hammer, not the slide. Second strike capability is there because the trigger cocks and releases the hammer. In order to chamber the first round, you still have to rack the slide, but doing so doesn’t cock the hammer. Racking the slide will load the pistol, but not cock it. Pressing the trigger performs two actions–cocking the hammer, then releasing it. Every shot after that is also double action. The Ruger LCR .38 Special is an example of a DAO revolver, and the Walther P99 is an example of a DAO pistol.
What are the benefits of a longer and heavier trigger pull that comes with a DAO pistol? There is a different distance the hammer falls in DAO versus SAO mode, which is one advantage. SAO firearms typically require the hammer to be a lot further from the primer than DAO guns. Because the DAO hammer has a shorter distance, there is a decrease in the time and hammer motion that can mess with the sight picture, which increases accuracy. Some DA/SA concerns are resolved by DAO guns by making each shot a DA shot. Training and practice are simplified because there is no difference in press weights. It is also often claimed that accidental discharges happen rarely due to the heavier trigger press, and many police departments require either certain heavier triggers or DAO guns themselves. Safety plays a role. Dangerous situations are minimized because DAO pistols cannot be manually cocked. Because of this, DAO guns are popular with law enforcement, however, many argue that safety is a matter of training and learned through practice. The best safety is your brain.
