Single action firearms changed the course of firearm development in the form of revolvers, and then got further refined and transformed into double action. While the single action is considered old-fashioned these days, double action can be further classified into double action only and single action/double action.
Learn about the good and bad for each and this will help you understand if one is better over the other.
Single Action vs Double Action
Here are some quick pros and cons for the single vs double action debate. Take a quick overview of their best benefits/drawbacks and suitable applications.
Single Action
Double Action
Pros
Single Action
Robust and lightweight frame
Can be carried cocked or uncocked
Lightweight, short, and clean trigger pull
Helps conserve ammo and practice accurate aiming
Uncomplicated design and minimal moving parts. Hence more reliable
Double Action
Always ready to fire with a chambered round
Trigger pull weight doubles as a safety feature
Single handed operation and quicker rate of fire
Trigger pulls cocks and releases the hammer. Two-in-one operation
Cons
Single Action
Limited applications in today’s scenario
Double handed and slow operation (generally)
Generally, SA revolvers aren’t very easy to conceal
Double Action
Some designs cannot be decocked
The exact position (cocked/decocked) is not always visible
Long and heavy trigger pulls require practice and may impede accuracy
Best For
Single Action
While single action revolvers are only good for hunting and recreational use, SA pistols have a shorter, cleaner pull and are great for competitions, hunting, or self-defense.
Double Action
Pure double actions or DAO revolvers and semi-auto pistols are good for almost every handgun application. But they require some practice to adhere to the pull weight.
What Does Action Mean in a Gun?
If I try to explain it In absolutely simple layman terms, the action of a gun is the place where all the ‘action’ happens. This includes the chambering, firing, and ejection of the cartridge. So basically, the action is like the engine of a firearm and also the most important component.
Actions can be broadly classified into two types, namely, single shot actions and repeating actions. These are further classified into numerous categories based upon the type of firearm. Single shot actions typically hold a single round and have to be manually reloaded/cycled after each shot. Initial designs like the breech block, tilting block, and revolvers or rifles without magazines are put into this category.
On the other hand, repeating action firearms can hold multiple rounds and are capable of performing cycling and ejection operations with minimal manual effort. Almost all magazine-fed firearms fall under this category and also include semi-auto and full-auto firearms.
What Does Single Action Mean?
Single action had been the primary action mechanism of firearms since their invention and up to the late nineteenth century. Prior to the invention of the modern metallic cartridges during the late 1840s, the revolving cylinder design was the most recent advancement in firearms and used percussion-based cartridges for firing.
We will take up the definition of the single action in the modern context for relevance. A single action firearm represents an action where pulling the trigger only releases the hammer to fire the chambered round. Each successive round has to be chambered manually by cocking the hammer.
The single action’s most relevant and practical example is the revolver. Especially the old models like the Colt Single Action Army (a.k.a Colt Peacemaker) and Smith & Wesson Model 3. Those old wild-west Hollywood movies where the shooter quickly fires the revolver while fanning the hammer from the other hand is what’s called a single action revolver.
Other than revolvers, single shot shotguns (single/double barrel) and single shot bolt actions are good examples of single actions. While single shot revolvers became obsolete before the onset of the twentieth century, they are still preferred by many civilian users for recreational purposes, historical value, and even serious applications like self-defense.
What Does Double Action Only Mean?
In a double action firearm, a single complete pull of the trigger does two tasks. It cocks the hammer and also releases it. This allows for a quicker rate of fire and a true single-handed operation. In double action revolvers, the trigger pull also helps with rotating the ammo cylinder and hence chambering a new round.
The Colt Model 1889 revolver was the first true double action design. It is also important to remember that some of the double action designs are strictly double action, whereas some combine the features of a single action as well and are called SA/DA firearms. I’ll elaborate more on that in one of the upcoming sections
The double action only (DAO) firearms do not allow the user to keep the hammer cocked. This means that every trigger pull is going to be long and a bit heavy because the hammer has to be worked out. This is the reason why single actions have a comparatively lighter trigger pull.
The DAO firearms either have the protruding hammer shrouded or cut off to eliminate the cocking/decocking function and also prevent snagging of the hammer with clothing. DAO handguns are considered a bit safer and offer consistent pull weight, but generally feature short barrel snub-nose designs with lesser accuracy.
Relevant Characteristics Between Single Action and Double Action
Let’s find out more between single and double action.
 | Single Action | Double Action |
|---|---|---|
| Hammer Cocking | Manual Pull | Trigger Pull |
| Trigger Pull Travel | Very Short | Long |
| Trigger Weight | Lightweight | Heavy |
| Reloading Speed (for Revolvers) | Very long for some designs | Comparatively Shorter |
| Flip-out Cylinder | No | Yes |
| Safety | Less | More |
| Barrel Length | Mostly Long | Mostly Short |
| Accuracy | High | Low |
| Rate of Fire | Low | High |
| Handling | Can be Clumsy | Easy and Simple |
| Durability | More | Comparatively Less |
| Ergonomics & Aiming | Better | Depends on Model |
| Cleaning | Difficult | Very Easy |
Similarities and Differences
Each of these action designs has been fairly popular and is still relevant in today’s advanced market. However, in order to choose one between these two, it is important to understand the similarities and differences, and if one has some edge over the other.
Single Action and Double Action Differences
Check out the major differences in characteristics and function of these two actions and what benefits/drawbacks each of them offers:
Trigger Function
The first and foremost difference between single and double action firearms (especially revolvers) is the function of the trigger. While a single action firearm has to be manually cocked by pulling back the hammer, the trigger of a double action firearm both pulls the hammer and releases it with a single stroke.
Trigger Travel and Pull Weight
The significant difference in the trigger function further transcends into affecting its travel and pull weight. Since a double action trigger has to do the extra job of cocking the hammer, it has a longer travel distance and an extra pull weight to work the hammer.
This extra travel and weight can affect the accuracy of the shooter, especially when taking quick successive shots.
Safety Features
Many people will argue that a double action design is inherently safer because of the heavy pull weight which discourages negligent discharges. However, I think that negligent discharges have more to do with training and awareness rather than such mechanical factors.
Double action or single action revolvers generally did not offer any extra safety features until the 1970s. So things like an empty chamber or keeping the gun decocked were the only alternatives. However, modern designs feature a transfer bar safety mechanism that doesn’t actuate the firing pin until the trigger is pulled.
Viewed from a different perspective, I think that today single actions can be slower but they are safer and promote more contemplation into shooting each shot rather than ‘spray-’n-pray’ with semi-auto guns.
Durability, Ergonomics, and Aiming
Single action revolvers generally prove to be more durable than double actions because of the lesser moving parts and thicker frame walls. Single action revolvers have a distinctive more curved grip compared to double action and as a result, offer a different (and often better) aiming experience along with better handling of recoil.
Single vs Double Hand Operation
Since with a single action revolver, the hammer will have to be cocked manually after each shot. The shooter will either have to loosen the grip and aim again or use another hand for patting the hammer (the technique is known as ‘fanning’). Double actions do not have such issues and allow single-handed operation and quick follow-up shots.
This difference is one of the major reasons why people prefer DAO revolvers for self-defense or active duty applications.
Single Action and Double Action Similarities
After elaborating on the differences, let’s now take a look at the similarities between these two actions:
Both Serve the Same Function
Despite the slight difference in their mechanisms, both SA and DAO actions do the exact same thing, which is cocking the hammer and releasing it. While the SA does it in two steps, the DAO does both of them at once.
Flip-out Cylinders in Revolvers
Yes, I know this may sound a little bit contradictory to my statements in the comparison table. However, it is still like an inconspicuous similarity that is often overlooked.
Most people think that single action revolvers always have a loading gate mechanism and not a flip/swing-out cylinder like double action. The truth is that flip-out cylinder designs never became too popular and even today, every major revolver manufacturer offers at least one SA design with a flip-out cylinder.
No Significant Difference in Accuracy
Given all other factors are similar, like the quality of the firearm, caliber, barrel length, and ballistical or environmental factors. A single action firearm will deliver accuracy similar to a double action firearm. However, this is for relaxed single shot situations and not for quick successive shots.
What About SA/DA Firearms?
The SA/DA or Single Action/Double Action line of firearms is a hybrid of the single and double action trigger system. Most double action firearms (especially handguns) you find today are not purely DAO (Double Action Only) but a mix of the single and double action mechanisms.
In a SA/DA mechanism (otherwise known as DA/SA), the user may or may not be required to manually pull the hammer back before the first shot. For example, DAO revolvers generally feature a shrouded or trimmed hammer spur, whereas SA/DA revolvers have an exposed hammer spur. So the user can either cock or decock the hammer anytime. Keeping the hammer cocked helps with quicker initiation of fire by reducing the trigger pull of the first shot.
Most semi-auto pistols available today use the SA/DA mechanism. The user may carry such a handgun with a loaded chamber and an uncocked hammer. So that when the user is ready to fire, the double action mechanism cocks and releases the hammer, and the subsequent shots are chambered by the force of the moving slide.
After the initial round, all the consecutive rounds will be fired in single action mode. Additionally, handguns featuring this mechanism come with multiple safety features, hence further enhancing the carry experience.
The SA/DA pistols gained popularity after the introduction of Walther PPK on the market. Almost everyone prefers the SA/DA mechanism over the DAO because of the increased versatility. On the contrary, the DAO handguns make sure that the hammer is uncocked after each shot. After the Glock handguns popularized the striker firing mechanism, exposed hammer DAO pistols declined quickly in terms of popularity. Although each of them has its pros and cons, the majority of firearms used these days work on the DA/SA trigger mechanism.
Bottom Line
Single action firearms (especially revolvers) were a very crucial and popular innovation of their time, which was before the invention of the modern metallic cartridge. Since in a single action firearm, the hammer has to be cocked manually and the trigger only releases it to hit the firing pin. SA weapons naturally have a slow rate of fire. Although their frame is very robust, they are considered to be more ergonomic handguns.
SA guns are mostly preferred by purists, collectors, and enthusiasts of traditional firearms. Plus, the only true single actions are the traditional revolvers.
The Double Action Only mechanism allows the hammer to be cocked and released with a single pull of the trigger. While this allows for simple one-handed operation and a quicker rate of fire, the trigger pull becomes heavier due to that extra lifting of the hammer.
A great compromise between these two is the SA/DA mechanism that combines the features of both these actions in a single unit and is used in almost every semi and full auto firearm made today.
People Also Ask
Check out a few facts and additional info about the debate between single and double action trigger mechanisms.
The first double action revolver was patented by an Englishman named Robert Adams in the year 1851. The first successful DA revolver was the Beaumont Adams percussion revolver adopted by the British Army in 1856. The next big name was the Colt 1877 and the double action revolvers were popularized by the introduction of the Colt Model 1889.
