What is the difference between Single Action and Double Action? In a single action (SA) firearm, the trigger performs only one function: releasing the hammer or striker that has already been manually cocked. This results in a lighter, shorter trigger pull, which generally improves accuracy. Many classic revolvers and 1911-style pistols operate in single action, requiring the shooter to cock the hammer before the first shot—though semi-autos often cock it automatically after each round.
In a double action (DA) firearm, the trigger both cocks and releases the hammer or striker, allowing the gun to fire from an uncocked position. This means a longer, heavier trigger pull but quicker readiness from a holstered position.
Some guns are DA-only, while others (like many Berettas or SIGs) are DA/SA, firing the first shot in double action and subsequent shots in single action as the slide re-cocks the hammer.
| Trigger Type | How It Works | Key Benefits | Considerations |
|---|---|---|---|
| Single Action (SA) | Trigger releases a pre-cocked hammer or striker | Short, light trigger pull; high accuracy potential | Must be cocked before firing; requires extra steps for safe carry |
| Double Action Only (DAO) | Trigger both cocks and releases hammer for every shot | Simple to operate; long pull reduces accidental discharges | Heavy trigger pull; not ideal for precision shooting |
| Double/Single Action (DA/SA) | First shot is double action; follow-ups are single action | Good balance of safety and accuracy after first shot | Learning curve for trigger transition; more complex controls |
| Striker-Fired | Striker partially cocked by slide; trigger completes and releases it | Consistent trigger pull; simple, fast operation | Requires quality holster for safe carry; limited manual safeties |
Single Action Pistols
The original type of firing mechanism and trigger system is single action, and an enormous number of single action firearms are still produced. That said, they are also very simple to operate for the most part. Single-action guns have to be cocked before every shot, and pretty much all single action guns are hammer-fired. Cock, then fire. Repeat.
Fairly simple, really.
However, there difference between single action revolvers and single action semi-auto pistols. Single-action revolvers have to be manually cocked before every shot. Semi-auto single action pistols, however, can be cocked manually or by the cycling the slide. The latter operation can be achieved by charging the pistol (racking the slide) or after a shot is fired, so these pistols at most will only need to be cocked once.
- For the concealed carrier, single action handguns impose certain concessions. The pistol has to be carried in one of the following manners:
- Pistol loaded, hammer down Sometimes called Condition 2, the pistol is charged (meaning loaded and a round chambered) but the hammer has been manually de-cocked. The hammer must be cocked before firing. Revolvers can be carried in this manner, but older handgun designs (meaning pre-1900) lack a drop safety, which is why many people carried with the hammer down over an empty chamber.
- Cocked and locked. This method of carry is only possible with a single-action semi-auto, such as a Browning Hi Power or or other single-action pistol with a manual safety. The pistol is loaded, a round is chambered, the hammer is back but the manual safety is engaged. To fire, the safety has to be deactivated.
- Condition Three or Israeli carry. Also possible only with a semi-auto, this is where a magazine is inserted but the pistol is not charged. To fire, the gun must be drawn, charged, then fired.
While it may seem that the single action system poses disadvantages, it remains popular enough for almost every major handgun maker to still make at least one single action firearm.
Double Action Only
Double action only, or DAO, is a double-action pistol without the option for single action operation. Revolvers or semi-autos are available in this configuration.
DAO pistols usually have an internal hammer. There are several reasons for this, firstly being that an exposed hammer is unnecessary since the pistol cannot be manually cocked. Secondly, DAO pistols are popular as concealed carry pistols and enclosing the hammer streamlines the pistol for easier concealment and drawing from concealment.
DAO pistols cock and fire the pistol with every shot, so the trigger pull is usually stiff (8 pounds or more) but can be tamed with aftermarket trigger springs.
These pistols are very simple to use - load and pull the trigger to fire. The long, hard trigger pull guards against accidental discharge.
While DAO pistols can be revolvers or semi-autos, revolvers are most popular. Commons examples include certain models of the revolver series by Smith and Wesson, Ruger's LCR, certain Charter Arms snubbies and so on. Popular DAO semi-autos include Kahr pistols (which are only offered in DAO) and the Smith and Wesson SDVE series.
Double Action/Single Action
Double action/single action, also called DA/SA, is a firing system where both double action and single action operation is possible. Both revolvers and semi-autos are offered in this configuration.
Pistols with this firing and trigger system are almost always hammer-fired, though there are some exceptions like the Walther P99 and the Canik TP9, essentially a P99 derivative. These guns are striker-fired (more on that later) but have double-action and single-action capabilities. However, the standard DA/SA pistol is hammer-operated.
DA/SA revolvers couldn't be simpler. Load, then either fire double-action by pulling the trigger or cock and fire in single action mode. Then repeat. Double action autos, on the other hand, can be slightly more complicated. The semi-auto DA/SA pistol is placed in single action mode when loaded and charged, so the pistol has to be decocked for a double-action shot to be made.
DA/SA guns have a long, stiff double-action trigger pull (usually 10 to 15 pounds of pressure are required to fire) which cocks and fires the pistol or a short, crisp single-action pull (4 to 6 pounds) to fire with a cocked hammer.
For the latter, the pistol must be cocked manually in the case of revolvers or decocked semi-autos, or by racking the slide or firing a semi-auto pistol. Semi-auto pistols, when carried loaded in double action mode, will go into single action mode after the first shot.
Some DA/SA semi-autos have a manual safety, enabling cocked-and-locked carry in single action mode but can be carried in double action mode if manually decocked, such as CZ pistols and CZ clones.
Some feature a manual safety that also decocks the pistol when engaged, like Beretta or Heckler and Koch pistols; this mechanism allows the user to carry in double action mode with the safety on if desired. Some have a decocking lever only, such as many Sig Sauer pistols, which allow the user to put the gun in double action mode after cocking...but no manual safety can be engaged.
Double action guns, when carried in double action mode, are less prone to accidental discharge, due to the long, hard trigger pull. However, some shooters find the long, stiff double-action pull is not to their linking or impacts their accuracy. This can, however, be overcome with practice.
Additionally, the manual safety/safety-cum-decocker/decocking lever operating procedures can be more complicated than some shooters prefer.
Striker-Fired Pistols: All The Rage These Days
Today, the dominant firing mechanism and trigger system is the striker-fired pistol. Popular models are made by numerous manufacturers, though is far and away the best-known and most popular. Striker-fired pistols are only semi-auto, since striker-fired revolvers aren't generally made.
A striker-fired pistol is fairly simple, in that a spring-tensioned striking rod strikes the pistol primer and discharges the round instead of the firing pin or a hammer. However, in striker-fired pistols, the striker is part of the firing pin, whereas the firing pin in other pistols is a single piece.
When the handgun is charged and loaded, the striker is half-cocked. Pulling the trigger fully cocks and discharges the pistol. The cycling of the slide half-cocks the striker again.
Trigger pull is light, usually 4 to 7 pounds. Operation is simple - insert magazine, rack the slide, start shooting. For concealed carry, that means you're able to begin shooting as soon as you can get the gun out of the holster.
However, these pistols have to be carried in a holster that fully protects the trigger guard. Accidental discharges have been documented where a striker pistol was fired when a piece of clothing or something else got into the holster and was able to operate the trigger.
Choosing The Single Action, Double Action, SA/DA or Striker Fire Pistols
Which firing mechanism and trigger operation is right for you is something that you'll have to find for yourself; some people swear by single action, some by double action and others insist that striker pistols are the pinnacle of handgun design. Each has their benefits and drawbacks, as you have read above.
To find what would be best, consider what sort of safety measures you want for a carry gun. Some believe the fewer the better, some want a few redundancies.
If at all possible, try to rent a few pistols from a range that has guns available for rent. You should be able to get a feel for what works best for you.
FAQs
1. What is the main advantage of double action for concealed carry?
Double action firearms offer the advantage of immediate readiness without needing to manually cock the hammer, making them faster to deploy in self-defense situations and safer to carry due to their long, heavy trigger pull which reduces the risk of accidental discharge.
2. How does a decocker work on a DA/SA pistol?
A decocker safely lowers the hammer on a DA/SA pistol without firing the weapon, allowing the user to carry or store the gun in double action mode without manually lowering the hammer by hand, which could be dangerous.
3. Are striker-fired pistols considered single action or double action?
Striker-fired pistols are typically considered partially double action because pulling the trigger completes the cocking of the striker and releases it, though some designs mimic single action characteristics with lighter and shorter trigger pulls.
4. Why is trigger pull weight important in firearm operation?
Trigger pull weight affects both safety and accuracy; heavier pulls are safer for carry but can reduce precision, while lighter pulls allow for more accurate shooting but may increase the risk of unintentional discharge.
5. What is Condition One carry and how does it apply to single action pistols?
Condition One carry refers to a loaded single action pistol with a chambered round, the hammer cocked, and the safety engaged—commonly known as “cocked and locked”—and is favored for rapid deployment while maintaining safety.
6. Can a single action revolver be safely carried with all chambers loaded?
Most single action revolvers should be carried with the hammer resting on an empty chamber to prevent accidental discharge from a dropped gun, unless the model includes a modern transfer bar or hammer block safety.
7. Why are double action only (DAO) pistols popular for law enforcement?
DAO pistols are popular in law enforcement due to their consistent trigger pull on every shot, reduced chance of negligent discharge, and ease of training officers on a single trigger system without needing to master both DA and SA modes.
8. What role does the trigger reset play in shooting performance?
Trigger reset is the point at which the trigger returns far enough forward to re-engage the sear for the next shot; a shorter reset allows for faster follow-up shots, improving shooting speed and efficiency, particularly in competitive or defensive scenarios.
9. Do modern striker-fired pistols have external safeties?
Most modern striker-fired pistols do not have external manual safeties and instead rely on internal safeties, such as trigger safeties, firing pin blocks, and drop safeties, to prevent accidental discharge.
10. What are the training implications of using a DA/SA pistol?
Training with a DA/SA pistol requires mastering two distinct trigger pulls—the long, heavy double action and the light, short single action—demanding additional practice to ensure consistent accuracy and safe operation during transitions between modes.