Single action double action da sa sao

[BEGINNERS GUIDE] Single Action, DA/SA, or DAO: Which One Is Right For You?


One of the choices the beginning concealed carrier has to make is the type of firearm to carry. The majority choose the semi-automatic or auto-loading pistol, but there is a strong minority who favor the revolver. This decision, combined with the choice of round to be used, determines the type of training required to become a safe and proficient shooter. Aside from safety, which is the first priority in firearms training, quick and efficient operation of the firearm is something all beginners should strive to master. In the reviews appearing on Concealed Nation, we often categorize firearms by their mode of operation. In this article we will break down the terms used and discuss how different modes of operation can affect your training.

Single Action vs. Double Action

These terms originally applied to revolvers, simply because revolvers were invented and widely used before semi-automatic pistols came on the scene. Before the invention of the revolver, hand-held firearms were of the single-shot, muzzle-loading variety. The means of ignition could vary. The matchlock gave way to the wheel-lock, which was succeeded by the flintlock. The percussion cap came later, followed by the self-contained metallic cartridge. Back in the muzzle loading days, if you wanted a repeating firearm, you had to have separate multiple barrels. You can see some of these early repeaters in museums. They were heavy and not very easy to conceal. The metallic cartridge era saw the introduction of the double-barreled “derringer” invented by Henry Deringer in the mid-1800’s. The original pistol was a single-barreled model. In 1866, Remington introduced a double-barreled over-and-under model. Deringers are still produced today by such firms as Bond Arms and American Derringer Co. Both firms offer models in .45 Colt/.410, which can serve as potent hideout or backup guns.

Ruger Blackhawk

Ruger Blackhawk

The revolver was invented to offer a repeater with more rounds on tap. It is with the revolver that we see the origin of the terms “single action” and “double action.” A single action revolver requires the hammer to be manually cocked before each shot. Cocking the hammer also rotates the cylinder, bringing a fresh round into alignment with the barrel. Once cocked, the SA revolver requires a short, light press of the trigger to fire. To fire again, the hammer must be re-cocked. The Colt Model 1873 or “Peacemaker,” also known of the “Single Action Army,” is an iconic firearm of this type. Today, the successor to the original Colt Patent Firearms Manufacturing Co. offers the Peacemaker® to collectors and nostalgic shooters. Ruger offers the thoroughly modern Blackhawk® and Super Blackhawk® which are made of modern materials and chambered for the powerful .357 and .44 Magnum rounds. Also offered is the Vaquero®, which combines the look of the Old West with modern design and high strength materials. These guns are strong and durable, and appeal to hunters and Cowboy Action shooters.

The double-action revolver, by comparison, uses a long pull of the trigger to cock the hammer, rotate the cylinder, and fire the piece. Repeated shots may be fired by repeatedly pulling the trigger until all rounds have been fired. Many DA revolvers may be thumb cocked and fired in single-action mode as well, while some have enclosed hammers and may be fired only in double action mode. Smith and Wesson and Ruger both produce double action revolvers in a wide variety of sizes, barrel lengths and chamberings. The DA revolver was the standard sidearm of US Police forces until the late 1980’s, when high-capacity semi-automatic pistols became popular.

A Crucial Difference

The DA revolver offers a tremendous advantage over the SA in that the swing-out cylinder allows the user to rapidly eject the empty cartridge cases and reload. In a SA revolver, the cylinder is fixed, and the piece is loaded one at a time through a loading gate on the right hand side of the frame. Loading and ejecting one at a time takes significantly more time than reloading a DA revolver. This speed of reloading is offset by the increased difficulty of trigger control. The long, relatively heavy double-action pull takes significant practice to master, compared to the short, clean break of a single-action. For those who master it, double-action rapid-fire technique places the DA revolver on a par with the auto-loader as a defensive firearm.

On to the Auto-Loader

Borrowing somewhat on the terminology developed for revolvers, semi-autos may be characterized. A single action autoloading pistol requires the exposed hammer to be cocked before the piece can be fired, with a light, clean break of the trigger. Examples are the 1911 and Browning Hi-Power.  Although one can carry these guns either with an empty chamber or with the hammer down on a loaded chamber, neither of these conditions is recommended. The correct way to carry a 1911, Hi-Power or other single action pistol is with a round in the chamber, hammer fully cocked, and the manual safety engaged. This “cocked and locked” condition is perfectly safe for a shooter with the proper training. It is also very fast. When drawing the 1911 or Hi-Power from concealment, one should place the thumb of the firing hand on top of the thumb safety and the trigger finger alongside the frame. The safety may be snapped off as the piece comes into alignment with the target as the finger engages the trigger. In a different situation, the piece may be leveled at the target with the thumb resting on top of the safety. If the decision is made to fire, the safety may be disengaged instantly.


Needless to say, the technique of drawing and firing the SA auto-loader from concealment should be practiced thousands of times with an empty gun before live fire is attempted. With live ammunition, start slowly and strive for smoothness. Speed will come with repetition. It is also very important to practice re-engaging the safety and re-holstering the piece after firing has been completed. The payoff for the effort put into this training is that you have only one trigger action to learn, and you can learn to control your trigger extremely well, assuring the all-important ability to put the first round on the target in the minimum amount of time. When carrying a single-action auto-loader, use a holster which protects the thumb safety from rubbing into your body or any other object. Do not carry a SA auto-loader in a fanny pack with the safety and trigger guard exposed. Contact with other stuff in the pouch may take the gun off safe and press the trigger, causing an unintentional discharge. Safety is a matter of common sense and good habits.


Beretta 92 FS

Another type auto-loader is the “traditional double single action” or DA/SA. Some well-known examples are the Beretta Model 92, the P-38 of WWII fame, the Walther PP and PPK, the older Smith & Wesson models, such as the 4506 and 539, and the SIG 226. These pistols may be carried with the hammer down on a loaded chamber. Most (but not all) have a passive firing pin block to prevent the firing pin from reaching the primer of the chambered round unless the trigger is pulled fully to the rear. When drawn from this condition, the first long trigger pull cocks the hammer and lets it drop. Subsequent shots are fired from a hammer cocked state, as the recoiling slide cocks the hammer as it cycles to eject the fired casing and strip a fresh round off the magazine to chamber it. There may be a manual safety on the slide or the frame, or no manual safety at all, as on the SIG. In most cases, engaging the safety lowers the hammer. The pistol may be carried with the safety either engaged or disengaged.

Here we have a problem. After a draw from concealment, the first shot is fired with a long, heavy double action pull, while successive shots are fired with a much lighter and softer single action pull. Considerable training and practice are required to accustom the shooter to this variable mode of operation. Since the first shot is especially critical, the longer and heavier double action first pull must be carefully practiced. When firing is completed, the user must remember to lower the hammer and/or engage the safety before re-holstering. Again, this is a case where habituation must achieved through constant practice. I know some shooters who prefer to carry with the hammer down, and the DA/SA fills their need.



The DAO – A Step Backward

The DAO semi-automatic evolved as the result of a requirement on the part of various agencies to have a sidearm with the magazine capacity of the auto-loader, coupled with the simplicity of operation of the DA revolver. Like the DA revolver, the DAO has no external safety. A passive firing pin block may be part of the design. In the DAO auto-loader, the cycling slide places the exposed hammer on a “quarter-cock” position, or lifted just far enough to allow the firing pin to retract under the pressure of the return spring. All shots are fired from this position. There is only one type of trigger action to learn. No safety needs to be manipulated. If the finger is off the trigger, the gun is safe. Each trigger pull is fairly long and heavier than a single action pull. If this works for you, great. Personally, I do not care for it. The SIG 239 DAK and the H&K USP Variation 7 offer this type of operation. Some agencies feel that the DAO is a “safer” firearm than the SA or DA/SA auto-loader, but this is debatable.  There is also a belief that training is simplified, which makes sense, because only one trigger action needs to be learned and practiced.

Tossing the Hammer – The Glock and Its Imitators

There is one more important breed of auto-loading pistol, namely the “striker-fired” type, typified by the Glock family. The Springfield XD and the new S&W pistols, as well as the Kimber Solo are also striker fired. Glock calls their system the “safe-action” but it is really a variation on the DAO theme. Pistols like Glocks, XDs, and S&W M&P series are all striker fired. With such a firearm, the user experiences a trigger action similar to the “two-stage” trigger pull on the M1 Garand, Mauser 98 and other military rifles of WWII. A long, rather light “take-up” stage ends when the shooter feels increased resistance from the trigger. By increasing pressure, a clean break not unlike a single-action pull is experienced. There is no external safety, except for a little lever on the face of the trigger in some models. The Glock and its brethren have no external hammer. The firing pin or “striker” is surrounded by a spring which is compressed by a part called the “connector” which is linked to the trigger. When the end of the take-up stage is reached, the connector is levered down and out of engagement with the striker, thus letting it fly forward under spring pressure to indent the primer of the chambered round. After the take-up stage, the trigger may be released, thus returning the striker to its resting or safe position. The striker is impeded by a vertical block which is moved out of the way when the trigger is pressed past the end of the take up phase.

Triggers on striker-fired pistols have a distinct feel. People either love them or hate them. Judging by the popularity of Glock pistols, the lovers seem to be in the majority.

Even though this system sounds very safe, it has a particular vulnerability. Since the take-up stage requires rather light pressure, Glocks and similar pistols are prone to negligent discharge if proper trigger discipline is not observed. By this, I mean leaving your trigger finger on the trigger when re-holstering, allowing the trigger to be snagged foreign objects, or by using a holster which leaves the trigger guard exposed. When using a Glock, or any firearm for that matter, keep your finger off the trigger until you are on target and ready to fire. Remove finger immediately after firing has ended.


Each particular firearm has its own mode of operation. Some are more difficult to learn than others. Some require particular safety precautions. Some offer greater speed. Some require the disengagement of a manual safety. Whatever you carry, become totally familiar with your firearm through dry firing and handling practice. Observe the rules of firearm safety at all times. Stay safe.

About Greg | View all posts by Greg

Constantine is a semi-retired business owner and consultant who lives in the Northeast US. He is an NRA Endowment Life Member and an NRA Certified Instructor. He enjoys all shooting…

Constantine is a semi-retired business owner and consultant who lives in the Northeast US. He is an NRA Endowment Life Member and an NRA Certified Instructor. He enjoys all shooting sports as well as big-game hunting. Licensed to carry in over 30 states, he has carried daily for over 20 years and has instructed many novice shooters in firearm safety and basic shooting skills. His EDC (most of the time) is a Rock River Arms custom 1911 loaded with Federal 230 gr. HydraShok JHP. This is carried in a Mitch Rosen USD II Slimline IWB holster on a Mitch Rosen belt. A Chris Reeve Sebenza 25 and a SureFire LED flashlight round out the system.

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  • ShertzDude

    I am still a relative newbie to handguns ( I have owned 3, all striker fired polymer framed) and this was very informative! I would feel more at ease now with a revolver or 1911 to add to my safe.

  • Michael

    I have a Ruger LC9 which is on my side for every minute I’m awake. It is DAO with an external safety and magazine disconnect and a strong trigger squeeze. I am delighted with all of these features because I have to be very intentional about shooting it. I’ve heard so many complaints about this gun. I practice drawing it daily. The safety comes off with a simple sweep of the thumb right out of the holster and if you know how to properly squeeze a trigger and not pull it, there is no difference between a 2 lb or a 20 lb trigger. Also, after more than 1,000 rounds through it I’ve never had a malfunction. Of course, I have personal reasons for that too. :)

  • steve

    I have been carrying my Ruger Sr9c,since 2012.I have run about 1500 rounds through it.the gun is about as good as I can hope for,sizewise,it fits snugly against my hip with my Blackhawk Serpa holster.the safety system in the gun was very easy to understand and it performs great.I would suggest to anyone that they would feel very comfortable with this gun.