In this age of striker-fired handguns, DA/SA pistols seem like a relic of the past. However, for those who prefer hammer-fired guns, it’s worth understanding why they were first designed.
Double-action/single-action (DA/SA) pistols have been around for almost a century. But what’s so special about this system?
You may want to consider carrying a DA/SA pistol but don’t understand what its strengths and weaknesses are. It’s worth looking at this firing system to see whether it’s right for you.
What is a DA/SA Handgun?
Hammer-fired handguns are available in a variety of configurations: Single-action only (SAO), double-action-only (DAO), and double-action/single-action (DA/SA). In a SAO handgun, squeezing the trigger performs a single action — it releases the hammer. In a DAO handgun, squeezing the trigger performs two actions — it both cocks and releases the hammer.
SAO pistols typically have a manual safety that you can engage when the weapon is cocked to render it safe to carry. As you draw the SAO pistol from its holster, train to deactivate the safety with your thumb. DA/SA provides you with two options for firing the handgun.
One of the earliest successful examples of a double-action/single-action pistol is the Walther PP, which Carl Walther introduced in 1929. This design enables you to carry the weapon in a safe condition with the hammer down. Rather than having to cock the hammer or disengage the safety lever with your thumb, you can simply squeeze the trigger.
Subsequent variants of this weapon, including the famous Walther PPK and PPK/S, remain popular among collectors and for concealed carry.
However, as a double-action trigger pull is longer and heavier than the single-action variety, this can interfere with precision. In a DA/SA semi-automatic pistol, the reciprocating slide recocks the hammer after the first shot. As a result, every subsequent shot is single-action, making the trigger pull shorter and lighter.
Several DA/SA pistols have a combination manual safety/decocking lever. A prominent example is the Beretta 92FS/M9. In this system, engaging the safety also decocks the hammer, lowering it safely.
Another type of system, used in the SIG P226 series, is strictly a decocking lever. When you depress this lever, the hammer is decocked, returning it to its double-action mode.
In some designs, you can engage the manual safety with or without decocking the hammer, allowing you to choose whether to carry the weapon decocked or in Condition One. You’ll find this system on some hammer-fired HK handguns, such as certain USP variants.
Still other DA/SA pistols — a prominent example being the CZ 75 — have a manual safety akin to that of the M1911. This allows you to carry the CZ pistol in Condition One — hammer cocked, round in the chamber, safety on.
You can either carry the pistol in the same manner you would other weapons (hammer down and safety on or off), or with the hammer cocked and the safety on.
In Condition One, you disengage the safety lever with your thumb as you draw the weapon. This way, the first and second shots are both single-action and there’s no transition.
Safer than SAO?
Some gun owners feel nervous carrying a single-action only handgun because they don’t feel safe carrying a loaded handgun with the hammer cocked. Provided that the gun is not defective, this system is perfectly safe to carry.
However, if you prefer to carry a gun with the hammer down, a DA/SA system allows you to do that without suffering a serious detriment to speed. Whether you carry your gun with the safety on or off, all you have to do to fire is squeeze the trigger. It’s worth keeping in mind that the heavier first-shot trigger is not a substitute for practicing proper trigger discipline.
Some critics of the military adoption of the Beretta M9 argued that DA/SA could interfere with accurate firing. The reason for this is that when you fire the first shot, the trigger pull is longer and heavier. However, when taking the second shot, the trigger is shorter and lighter.
Some shooters find that this transition can cause the first shot to fly rather wide relative to follow-up shots. Others insist that this is minor and that you can reduce this transitional inaccuracy through practice. This system is still less difficult to master than dedicated double-action firing, like combat shooting using a Smith & Wesson revolver.
One advantage of a double-action/single-action pistol is that, in the event of a misfire, you can squeeze the trigger again to recock and release the hammer. Sometimes the reason for a misfire is that the cartridge primer failed to detonate because of a light strike.
In an SAO handgun, you would have to manually recock the hammer or retract the slide, opening the breech and ejecting the unspent cartridge. However, if this was a hang fire — i.e., delayed ignition — you don’t want your thumb on the hammer and in front of the slide.
You also shouldn’t risk opening the breech immediately. Most sources recommend waiting for one to five minutes to allow the primer enough time to detonate on its own.
The double-action systems, whether DAO or DA/SA, let you try again. Recocking and releasing the hammer by squeezing the trigger can also assist in fully closing the slide in some weapons.
While striker-fired weapons can have single- and double-action triggers and hybrids, these designs cock a striker. This is a type of spring-loaded firing pin. While some would insist that hammer-fired pistols are obsolete, there’s still a dedicated following.
To understand better the basics of striker-fired pistols, read this article.
The Next Step
When searching for a suitable handgun for concealed or open carry, don’t discount hammer-fired DA/SA pistols. They were popular for a reason, and many of them are still highly serviceable defensive weapons.
With practice, you can familiarize yourself with the trigger pull difference from the first shot to the second. It also affords second-strike capability for light-strike misfires that neither SAO nor modern striker-fired handguns permit.
DA/SA pistols have been around for years, and they don’t seem to show any sign of disappearing. It’s worth understanding how and why they work. You may decide that this system works better for you than the alternatives.