Firearms

What Is Selective Double Action?

CZ 75

Among the most misunderstood action types is the selective double-action handgun. The SDA is among the best suited to some types of shooting and compliments individual shooting styles well.

It isn’t for everyone, but has proven to be a good choice for shooters who take time to understand the type.

Let’s look at a few definitions first. Single-action self-loading handguns feature a trigger that does one thing, drops the hammer or releases the striker.

The slide is racked and the pistol is cocked and ready to fire. The trigger is pressed and the pistol fires. For many years, the majority of handguns were single-action.

The Little Tom, a small pocket pistol, was among the first double-action handguns. This handgun used the trigger action to both cock and drop the hammer.

The trigger is pressed and a trigger bar moves the hammer to the rear. The hammer trips the sear and drops, firing the handgun.

In a double-action-only handgun like the Little Tom, the action is the same for every shot. The SIG P250 is another example. A double-action first shot pistol operates differently.

The trigger presses the trigger bar and the hammer is cocked, trips and fires.

The slide recoils, but the difference between the double-action-only handgun and the double-action first shot handgun is that the double-action first shot handgun is double-action for the first shot.

Then the slide recoils and cocks the hammer for subsequent single-action fire.

CZ P-01
A late-model CZ P-01. This pistol is a double-action first shot with a frame-mounted decocker.

How Selective Double Action Works

When the double-action first-shot handgun is loaded, there must be some means of lowering the hammer safely. The trigger may be pressed as the hammer is held and safely lowered to the ready position.

The CZ 75 operates in this manner. Others, such as the Beretta 92, feature a manual safety/decocker that is actuated to lower the hammer without touching the trigger.

The selective double-action self-loader is another variation. Early versions of the Beretta 92 were selective double action. They featured a frame-mounted safety that made cocked-and-locked carry possible.

The Taurus PT92 was patterned after the early Beretta 92 and built on machinery originally intended to fulfill a military contract for the Beretta, so it made sense to not redesign the pistol.

Later, Taurus retained the selective double-action feature, but added a decocker. The original CZ 75 and most present versions are selective double action.

(The CZ 75 has been produced in DAO and decocker versions as well.)

A selective double-action pistol operates much like a single-action pistol. The handgun is loaded and then the hammer must be manually lowered by pressing the trigger as the thumb lowers the hammer.

A long press on the trigger cocks and drops the hammer. After the pistol fires, the hammer is cocked by the slide and subsequent shots are fired in single-action mode.

This is where things are both interesting and different.

Selective Double Action
When Beretta adopted many of the features of the Walther P38 into the Beretta 92 9mm, they used the trigger action and trigger of the Walther, and the oscillating-wedge lockup, but they did not use the Walther decocking safety during initial production.

Italian police asked for a decocker version and that is the Beretta 92 that was adopted by the U.S. Army. The Czech military kept the original selective double-action CZ 75.

The term selective double action is used because the pistol may be fired either double-action first shot or single if carried cocked-and-locked.

Most double-action first shot pistols may be fired by simply cocking the hammer for a single-action shot if preferred.

The CZ, however, may be carried with the hammer cocked and the safety on, cocked-and-locked, in the manner of the Colt 1911 or Browning Hi-Power.

This allows for more options. However, for those that prefer a double-action first-shot pistol, I believe that the selective double-action pistol offers a tactical advantage over any pistol with a slide-mounted decocker.

The greatest advantage may be that the safety of the CZ 75 pistol is frame-mounted and much more ergonomic than any slide-mounted safety.

three handguns
Top to bottom: double-action-only, single-action and double-action first shot pistols.

Advantages of Selective Double Action

The advantage is in tactical movement.

Once you have worked through the double-action trigger press and the pistol is firing in single-action mode, you do not have to decock the action as you would with a decocker-type pistol to make the handgun safe, hammer down, for movement.

To make the pistol safe during movement, simply place the safety on. When you wish to fire again, you need only thumb the safety to the on position and you have a crisp single-action trigger.

With the decocker-type handgun, to make the piece safe during movement, you would have to decock and then work through the long double-action trigger again to fire.

Most shooters do not like doing tactical movement with a cocked pistol in the single-action mode.

The choices are there. For most civilians, the decocker-equipped CZ pistols such as the P-01 may be the better choice for general handling.

For those wishing to own a pistol with good shooting attributes — but who do not wish to deploy a single-action pistol — the selective double-action pistol has much to recommend.

As an example, the single-action 1911-type handguns must be carried cocked-and-locked for speed to an accurate first shot.

For home ready, most of us will lower the hammer and keep the piece ready in this manner, requiring the hammer to be cocked before firing.

With the SDA-types, the pistol may be at home ready and be fired simply with a first shot double-action trigger press.

The original CZ 75 did not allow the option of hammer down and safety on, the safety could only be applied with the hammer to the rear.

Taurus 9mm handgun
The Taurus 9mm is shown with the hammer fully to the rear and the safety on. While cocked-and-locked carry is viable, the author sees this advantage primarily in tactical movement.

A modern variation on the SIG P-Series design is the Arex Rex Zero 1. Many experienced shooters find this pistol is an improvement over the original SIG P220.

The decocker also serves as a slide release. This is important, as shooters often ride their thumb on the SIG slide lock during firing. The result is the pistol does not lock open on the last shot.

Moving the slide lock to the decocker lever offers rapid manipulation. Arex also added a manual safety. This safety may be applied when the hammer is down.

The Arex Rex Zero 1’s safety may also be applied when the hammer is cocked. This makes for among the most attractive selective double-action pistols available.

Another desirable selective double-action handgun is the Beretta Tomcat. The pistol features a double-action first shot trigger.

The safety may be placed in the on position when the hammer is down or when the hammer is cocked. A great advantage of the Tomcat is that the slide doesn’t have to be racked to load the chamber.

A tip-up barrel makes loading simple. This combination of features makes the Tomcat a superior pocket pistol in many ways, but it is also a pistol that demands attention to its unique manual of arms.

Selective double action is useful, but it must be practiced.

Beretta Tomcat
Beretta Tomcat is shown with the hammer down and ready for a double-action first shot.

Selective double action is one choice among many. Whether it is the first choice or the last choice for the individual is up to personal preference.

What do you think of selective double action? What’s your favorite SDA pistol? Let us know in the comments below.

About the Author:

Bob Campbell

Bob Campbell’s primary qualification is a lifelong love of firearms, writing, and scholarship. He holds a degree in Criminal Justice but is an autodidact in matters important to his readers. Campbell considers unarmed skills the first line of defense and the handgun the last resort. (He gets it honest- his uncle Jerry Campbell is in the Boxer’s Hall of Fame.)

Campbell has authored well over 6,000 articles columns and reviews and fourteen books for major publishers including Gun Digest, Skyhorse and Paladin Press. Campbell served as a peace officer and security professional and has made hundreds of arrests and been injured on the job more than once.

He has written curriculum on the university level, served as a lead missionary, and is desperately in love with Joyce. He is training his grandchildren not to be snowflakes. At an age when many are thinking of retirement, Bob is working a 60-hour week and awaits being taken up in a whirlwind many years in the future.


Published in
Black Belt Magazine
Combat Handguns
Handloader
Rifle Magazine
Handguns
Gun Digest
Gun World
Tactical World
SWAT Magazine
American Gunsmith
Gun Tests Magazine
Women and Guns
The Journal Voice of American Law Enforcement
Police Magazine
Law Enforcement Technology
The Firearms Instructor
Tactical World
Concealed Carry Magazine
Concealed Carry Handguns



Books published

Holsters for Combat and Concealed Carry
The 1911 Automatic Pistol
The Handgun in Personal Defense
The Illustrated Guide to Handgun Skills
The Hunter and the Hunted
The Gun Digest Book of Personal Defense
The Gun Digest Book of the 1911
The Gun Digest Book of the 1911 second edition
Dealing with the Great Ammunition Shortage
Commando Gunsmithing
The Ultimate Book of Gunfighting
Preppers Guide to Rifles
Preppers Guide to Shotguns
The Accurate Handgun
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (28)

  1. Re. George comment. I also keep my 1911s at home with hammer down. The 1911 has an inertial firing pin. The pin is not in contact with the primer when the hammer is down. Tests have established that it would require a significant drop for the pin to ignite a primer on either a muzzle down drop or a drop landing on the hammer. As I remember the articles it would take more than a 20 foot fall to ignite the primer on these inertial pin guns.

    Some people may prefer cocked and locked in the home with 1911s. I am ok with that. My preference is hammer down.

  2. don’t want to disagree but this is how I was taught in the ARMY 50 years ago.

    There are two actions that must be executed for ignition in a fire arm .
    1) cocking the hammer 2) dropping the hammer

    single actions firearms execute one action for each action of the operator,
    the operator must make two actions to achieve ignition.
    double action firearms execute two actions for each action ot the operator,
    the operator must make one action to achieve ignition.

    single action firearm ,two actions by operator
    double action firearm ,one action of the operator. don’t confuse the firearm and the operator,
    ,
    There single action and double action firearms , and also single action on first round firearms
    like the 1911, that requiers two actions by the operator on the first round , but the firearm executes as double action in each subsequent round unless the hammer is intentionally slowly dropped ( or decocked in firearm so equiped )

  3. I have a Canik TP9V2 which has a decocker. It does have a double action first shot, but an interesting feature is that a short quarter-inch “cock” of the slide resets the striker for a single action first shot. It takes very little effort to move the slide rearward and it eliminates that hard first pull.
    I don’t know if any of the other Canik 9mm autoloaders share this feature, but I really love this pistol.

  4. I have pistols with SA only, hammer drop decockers, and selective double action, and striker fired. I’ll take a pistol with a safety any day of the week being trained initially with a 1911 Colt. I don’t find pulling a pistol out of a holster while intuitively at the same time taking the safety off. My preference today is the Taurus safety where you can carry cocked and locked AND drop the decocker if needed…best of both worlds. And a CZ with selected D/A and cocked and locked is superb also! I have Glocks and under a panic situation I’ve heard quite a few stories of Glock Leg. Slight chance of that ever happening with a pistol with a manual safety. Great article by the way!!!

  5. I live in a Communist state that only allows me to carry 10 rounds in the magazine. So I now carry a CZ75 Compact. I carry 11 in the cocked and locked mode, I can react to the situation as quickly and efficiently as possible.

  6. I have a Ruger P95DC. Not being a lifetime pistol owner I was unaware what this action was called. I originally purchased the weapon for concealed carry. I always liked the hammer down when carrying and just having to pull the trigger when firing it.

    Thanks for your article. It answered questions I didn’t know I had.

  7. Sir,
    I disagree with the author where he wrote (about the 1911) “For home ready, most of us will lower the hammer and keep the piece ready in this manner, requiring the hammer to be cocked before firing,” this puts the pistol in a very dangerous condition as the hammer is laying directly on the firing pin over a loaded chamber and that one in a million chance that you drop the gun, it could go off and seriously hurt/ kill someone. If your going to use the 1911, or any single action pistol for self defense, it should be either left cocked and locked or unloaded. One should also consider that in the event you have to defend yourself, statistics show that you won’t have time to do anything but draw the gun, flip the safety off and fire. Chances are your brain is going to be in survival mode, it’s not going to be thinking of loading, cocking or doing anything but shooting the gun. Just my 2 cents, I think it was a good article overall.

  8. I agree with Greg 100%. I carry a Bersa thunder ultra compact. I carry with one round in the chamber at all times. Remove the pistol from the holster, point and pull the trigger. As simple as that.

  9. I have three versions of the CZ-75. The SP01 Tactical, the P01 Urban Grey, and the 2075 Rami, all with decockers. The DA trigger pull from the half-cock position is slightly shorter than from the full hammer down position.
    I don’t want to have to think about taking off the safety. I don’t want to have to commit “flipping off the safety” to muscle memory. In crunch situations, my lizard brain takes over. I want to be able to unholster, point, and pull the darn trigger! In that situation, I don’t care if the trigger pull is twice as long and twice as heavy, adrenaline is taking over, and I will not even notice.

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