So You’re a New Gun Owner? Semiautomatic Pistol Actions

Continuing in the theme of gun parts and how they work…

You may have heard a handgun referred to as a single action, double action, or a striker fired handgun. Obviously there’s a difference between these, but what does it mean, and why does it matter?

First, some simple definitions:

Double action: when you pull the trigger, two things happen – the hammer or striker goes back (it cocks) and is then released.

Single action: when you pull the trigger, one thing happens – the hammer or striker is released.

Hammer-fired: the handgun has an external hammer (which we saw in pistol parts) that strikes an internal firing pin. The firing pin then moves forward and strikes the primer, firing the round.

Striker-fired: there is no external hammer. Instead of a hammer/firing pin combination, there is an internal striker. When the trigger is pulled, it acts directly in the striker, either pulling it back and releasing is (double action striker like a Glock) or simply releasing it (single action striker like a Sig Sauer P320).


You’ll typically see handguns in one of three configurations:

Double action/Single action (DA/SA): on this gun, the first round is fired double action. Every round afterward is fired single action, because the recoiling slide cocks the hammer. These guns normally have a decocker to return the hammer to double action after firing is complete. Some guns in this configuration are the Beretta M9/92FS and the Sig Sauer P22X series (P220, P226, P229, etc.).

Double action only (DAO): this gun can only be fired in double action. These can be either striker fired (Glock) or hammer-fired (Sig Sauer P229 DAK and some of their DAO models as well as the P250). Often, if it is a hammer-fired DAO, the hammer will be bobbed (the hammer spur is ground off).

Single action only (SAO): this gun can only be fired in single action. These guns can also be either striker-fired (Sig Sauer P320) or hammer-fired (1911-style guns). For hammer-fired SAO guns, the hammer normally sits in the cocked position with a manual safety engaged.

Practical effects

Okay, so that’s a lot of technical language, but what does it really boil down to?

In general, double action guns have a heavier, longer trigger pull, meaning it offers more resistance when you pull the trigger and the trigger physically has to travel a longer distance before the gun fires. Single action guns are typically the opposite – shorter, lighter felt trigger pulls. You’ll notice this when you’re out shopping for a gun or when you’re practicing with the gun you bought.

Key point: with practice, either type of action can be shot extremely well and extremely accurately. It isn’t about the mechanics of the gun, it’s about the skill of the shooter.


Realizing that this was a very quick overview, I hope this has been useful for you. If you enjoyed, give us a follow and a share. Social media really limits our ability to advertise, and organic shares always have the biggest impact. If you think I missed something or have a question, drop a comment below. Alternatively, you can contact me via my Facebook page, Google Hangout, or email at guntoter.official (at)

Thanks for reading!

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