This article is not about triggers, per se. That information can be found at Trigger (firearms). What this article is about is some of my drafty opinions on using DAO, DA/SA, and SA triggers without unintentionally destroying something you did not want to destroy; life, limb, or other things. And when I talk about these triggers, both revolver and semi-automatic pistols must be included in the discussion, as these three trigger types are used in both.

If you did your homework and actually read the material at Trigger (firearms), then I do not need to go into detail about DAO, DA/SA, and SA triggers, but I do need to touch on them briefly.

The SA, or ‘Single-Action’ trigger is used in both revolvers and semi-automatics pistols.  SA revolvers, like the 1873 Colt Single Action Army, paved the way for winning the West. Single-Action revolvers are still being made today and enjoyed by many, but they are normally used for recreation, sport shooting, and hunting rather than for defensive purposes. The only job of the single-action trigger is to drop the hammer. Whether that hammer is dropped on a cartridge is an entirely different matter. It’s the operation of the trigger that matters.

SA Operation

In a revolver, when the hammer is pulled to the cocked position, the cylinder is unlocked, a hand rotates the cylinder until the next available chamber is located in-line with the barrel, at which point the cylinder is locked. This locking of the cylinder will happen just before or exactly when the hammer is locked into the cocked position.

With a semi-automatic pistol equipped with a hammer-fired system, the hammer is simply pulled back into the cocked position, or the slide is retracted fully to the rear or until the hammer is in the cocked position. As with the revolver, the chamber may be loaded or not.

Pulling the trigger to the rear releases the hammer from the cocked position, where it has been stored under spring pressure. The hammer falls forward until it either impacts the prier of a loaded cartridge, impacts a stop of some sort if the chamber is empty, or may impact the rim of the chamber (in the case of many .22 caliber revolvers and pistols).

If the hammers (or firing pin) falls on a primer of a loaded cartridge in a revolver (single-action or double-action), the cartridge is fired and that is it. No further action takes place until the hammer is again pulled to the cocked position. With a semi-automatic firearm, and if the hammer (firing pin) strikes the primer of a loaded cartridge, the cartridge fires and the slide cycles rearward to re-cock the hammer, extract and eject the spent cartridge case, and chamber up a new cartridge if one is available. With a semi-automatic pistol, the slide may remain rearward or it may return to the chambered position, which depends on the design of the pistol and if the pistol is operating as it should.

The trigger pull of any single-action firearm; whether revolver or pistol is usually very light and nominally in the range of 3 to 6 pounds of pull. Trigger management is essential to prevent unintended discharges. While there is no safety on a single-action revolver, most single-action semi-automatics have one or more means of preventing the hammer from dropping unintentionally. Some of the safeties must be manually activated by the user, while others are in place to prevent an unintended discharge if the pistol is dropped.

For a single-action revolver to be fired again, the hammer is simply moved rearward, once again, to the cocked position and the trigger is pulled. For a single-action semi-automatic pistol, the safeties are simply disengaged and the trigger is pulled, since the slide did all the work in chambering a cartridge and locating the hammer in the cocked position.

Rarely are single-action revolvers used for self-defense, except in rural or wilderness settings when bears or other furry woodland creatures that can eat you are around. Single-action semi-automatic pistols; however, is another story. The 1911-based pistol has been around since 1911 (officially) and is one of the more prolific single-action semi-automatic pistols in use today for protection and competition. Some claim that the 1911 trigger is the apotheosis of what a single-action trigger should be.  Some semi-automatic pistols are configured for both single-action and/or double-action operation. These are referred to as DA/SA pistols and will be discussed later in this article.

Single-action trigger operation takes discipline and sometimes training to become efficient with it. With a single-action revolver, if the shooter no longer wishes to shoot, the hammer is simply left in the forward position after a shot. This places the firing pin over an already expended case and there is no danger of an unintended discharge. The semi-automatic pistol; however, is ready to shoot at any time and the operator must be the controlling factor in placing manual safeties in their proper position to prevent the pistol from discharging. Primarily, this is in the form of placing the thumb safety in the ‘safe’ position. However, some single-action semi-automatic pistols do not have such a safety, but may incorporate another safety; for example, a grip safety. However, there are many single-action semi-automatic pistol that do not incorporate either of these safeties, but instead rely on the operator to simply not place their finger on the trigger until they are ready to fire or lower the hammer manually.

DA/SA Triggers

Often, we find Double-Action/Single-Action triggers on many firearms; revolver and semi-automatic pistols. With DA/SA triggers, the first trigger pull is usually in double-action mode, but that is not always the case, especially with semi-automatic pistols.

By default, DA/SA revolvers primarily operate in double-action mode; whereas, pulling the trigger rotates the cylinder into the proper position, cocks the hammer, and the hammer drops at a pre-defined point in the trigger pull. To place the DA/SA revolver in single-action mode, the operator must manually pull the hammer back to cock it, just like with the single-action revolver. As with the single-action revolver, the triggers only job is to release the hammer.

The DA/SA semi-automatic pistol normally incorporates what is called a safety/de-cocker mechanism. The Beretta 92FS, for example, uses a slide-mounted safety lever as both a safety and as a de-cocker. Pressing the safety lever down de-cocks the hammer to a ‘safe’ position. If the safety lever is left in place after de-cocking, pulling the trigger will not have an affect on the hammer; the hammer is disconnected from the trigger. When the safety is placed in the ‘fire’ position, the trigger again has influence over the hammer and pulling the trigger will cock and release the hammer. Most, but not all, DA/SA semi-automatic pistols operate in this fashion.

Once the trigger is pulled in double-action mode, and the pistol fires, the slide automatically moves rearward, extracting and ejecting the spent cartridge, cocks the hammer, and chamber another cartridge (assuming there is one to chamber). In other words, the pistol operates just like any other single-action semi-automatic pistol – until the safety/de-cocker mechanism is activated.

Carrying a DA/SA semi-automatic pistol in DA mode is a very safe way to carry this type of pistol. The double-action trigger pull weight is on par with most double-action revolvers; whereas, the pull is long and heavy, usually in the vicinity of 11-pounds of pull. In most cases, the trigger pull mimics that of a good double-action revolver where the travel is long but smooth. The first shot in double-action mode is, of course, long and heavy. After the pistol makes the transition to single-action mode, the trigger pull is shorter and lighter, just as with any single-action semi-automatic. Training is essential for the operator to make this transition from double-action to single-action work.

DAO (Double Action Only) Trigger

There was a period when ‘de-horning’ or ‘bobbing’ a hammer was a popular way to turn a DA/SA revolver into a DAO revolver. It also caused as many problems as it solved. But ‘de-horning’ or ‘bobbing’ a hammer was an efficient way to prevent a revolver from snagging against material from the draw. While several small-frame revolvers were sold with a ‘de-horned’ or ‘bobbed’ hammer, larger frame revolver usually went under a gunsmith’s hand to make them that way. I remember seeing my first Smith & Wesson with a ‘bobbed’ hammer, and I thought it very cool looking, and I wanted one. I never did get one, but I always wanted one. Today, not so much. The hammer does serve several purposes.

Aside from the ‘snag’ factor, the DAO revolver had one redeeming feature, shooting someone with a revolver in single-action mode was impossible. Why was that important? To summarize in one word, it’s called “litigation.” In some prosecuting attorney’s mind was seeded the thought that shooting someone with a revolver (or pistol) with the hammer back (as in the cocked position) meant that there was malice aforethought and reeked with premeditation. That would not have flown in the “Old West,” as single-action revolvers were the rule and not the exception. Of course, us shooters don’t look at it that way. We simply know that single-action is the most accurate way to take a shot. Before long, corporate attorneys and such were designing firearms, or at least having a direct impact on the design of firearms.

Shrouded and bobbed hammered version of revolvers came onto the marketplace, which was followed by DAO pistols, and I can’t say that’s a bad thing, at least from the self-defense aspect. A DAO trigger is consistent from pull to pull. I have pulled some good ones and I have pulled some bad ones. The standard concealed carry gun for much of the 20th century is still one of the best: the Smith and Wesson J-frame. The new Kimber K6S has an excellent DAO trigger, but I still can’t decide if it is better than the trigger on my Smith & Wesson 642; it is just different.

Some of these new “double action only” (DAO) pistols, such as the compact Kahr line of DAO autos or the Canadian Para-Ordnance LDAs, are remarkable in that their trigger pulls are lighter than that of a DA revolver and thus much easier to control compared to the older first-gen technology. However, and like Glock, there is no second-strike capability

Another is the Sig DAK series of pistols. “Double Action Kellerman”. It has a 6.5-lb. double action only pull. The specialty of DAK is that it has an “intermediate reset”, meaning that if you don’t let the trigger all the way out to a full reset it will still allow you to fire but it requires an 8-lb. pull from the intermediate reset position. Sig recommends that you train yourself to allow the full reset, but it has the intermediate reset as a backup option in case of short-stroking during a critical action. Then, there is the Glock trigger, which some have classified as a double-action trigger.

I would classify the Glock “Safe Action” as a DAO trigger, along with the BATF (The BATF classifies the Glock design as “double action only.”), even though its concealed striker is cocked by the short trigger stroke of 5.5 pounds, it does not offer second-strike capability. The manual of arms, in case of a cartridge malfunction, is the same as a single-action pistol (tap, rack, bang). But, is the Glock design something new and neither SA nor DA? Could we call it a PST (Pre-Stage Trigger)?

There have been, and continue to be, many developments designed to remove the specter of a cocked pistol while still making the weapon capable of being instantly fired. The reason for this development was safety. “Safety” might be a misnomer for a training issue, yet police agencies, militaries, civilians, and liability attorneys all seemingly desire a pistol that is ready to fire, but without the compressed springs or that frightening cocked hammer. In a defense situation, some experts have opined that it is an advantage to have a heavier first shot trigger squeeze to reduce the likelihood of a negligent discharge. Another stated advantage is that the double action (DA) auto allows for a defective primer to be struck a second time by a second trigger pull”. – Source: https://www.chuckhawks.com/trigger_options.htm

I like a DAO trigger, if there is a ‘staging point.’ I mentioned this in another article. The ‘Staging Point’ is a point in a trigger’s pull where the pull goes slightly slack. This is a point where the hammer has just cocked. Pulling the trigger just a bit further releases the hammer. In revolvers where the hammer is covered or ‘bobbed’ this staging point allows the user to get a second chance in ensuring that the sight picture is correct before committing to the rest of the trigger pull. Some revolvers are better than other in revealing the ‘staging point.’ In short, the ‘staging point’ allows you the precision of a single-action shot but it is still wrapped in the double-action envelope.

In a semi-automatic pistol, there is also a ‘staging point’ but it is not in the same sense as that with a double-action revolver. Normally with a single-action pistol, the take-up constitutes the ‘staging point.’ Except for the Glock pistols, pulling the trigger further release the hammer (or striker). With the Glock pistol, pulling the trigger past the ‘staging point’ completes the cocking of the striker before it is released.

Where All of this is Leading

This is the point where I need to say that I am not an attorney, nor have I pretended to be one in any shape or form. If you have questions about anything stated forward of this point, please consult with a real attorney.

The rated trigger pull for a Glock trigger is 5.5 pounds. For a Rock Island Armory 1911 pistol, the rated trigger pull is between 4 pounds and 6 pounds. These are values established by their respective manufacturers.  If you own one of these pistols, and happen to shoot someone with them, your firearm is going to be scrutinized to the nth degree. If you have yourself modified, or have had someone else modify, those triggers to less than the rated amount, you have just placed yourself in jeopardy.

You may have changed grips or changed sights to suit your preference. Both are normal “acceptable” upgrades. Lightening the trigger on a pistol used for self-defense if not a good thing to do, even though the accuracy may have improved and your handling of the trigger is for the better, the fact remains that the functioning and performance of the pistol has been changed because of the trigger modification.

A DA/SA revolver will also be examined to see if you fired one or more shots in single-action or double-action modes, which is usually indicated by the impact depth of the firing pin against the primer; whereas, a double-action primer strike will be deeper that a single-action primer strike. Ammunition will also be examined, but that’s a topic for a different article.

Any modification made to a firearm that affects the safety of the firearm, is a definite no-no. This includes magazine disconnects. In other words, simply don’t do it.

Even with a firearm where the trigger pull weight can be adjusted by the user, the user should refrain from doing so for any firearm that would be used for self-defense.

Point: Lightening the trigger pull helped me better control the pistol.

Counter-Point: So does training!

For any modification you make to your firearm, ensure you can articulate why you needed to make the modification. Being able to explain exactly why the modification makes the gun safer for you to use, and thus ultimately safer to the general public can help the jury understand why what you did was responsible and not reckless.

I; however, recommend not modifying the trigger pull weight on your carry gun. The factory specifications are more than acceptable for balancing accuracy, safety, and speed. If you don’t like the feel of the factory trigger on a firearm you are looking to purchase as your carry gun, investigate a different firearm that better sits you. If you don’t like the feel of the factory trigger on a firearm you are carrying or using for home defense, trade it, sell it, or use it strictly as a range gun, and then purchase a firearm with the best trigger for you.

If you are intent on modifying your trigger, limit the modification to the polishing of parts that will make the trigger operate smoother without affecting the pull weight of the trigger. Or have a trained gunsmith do the work so everything functions the way it was designed. However, remember that a not so good trigger out of the box, just might wear in to be an excellent trigger down the road.


About Taurian

Taurian is a U.S. Army veteran and former LEO and Defensive Tactics Instructor. Taurian also has over fifty years of experience as a Technical Writer and Training Program Developer. After leaving home at the age of ten without any shoes, Taurian continues on with many years devoted to the keeping and bearing of arms.

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