Single-Action vs. Double-Action

The action of a handgun is comprised of the parts that actually make the gun shoot. The terms “single-action” and “double-action” refer to what happens when you pull the trigger.

  • When a gun is shot single-action, a pull of the trigger does one thing—it releases the hammer. This means that the hammer must be cocked before the trigger is pulled or the gun will not fire.
  • When a gun is shot double-action, one pull of the trigger does two things—it cocks the gun and releases the hammer.

That is simple in principal. But a lot of people get confused by how to apply it to the many different types of revolvers and semi-automatics. A few points on single and double-actions may help you understand this:

  • You cock the hammer of a revolver by placing your thumb on the hammer and pulling it back.
  • You cock the hammer of a semi-automatic by “racking” the slide—that is, pulling the slide back and then letting it snap forward. When you have fired a shot in a semi-automatic, the racking and cocking occurs automatically because the shot causes the slide to rack automatically.
  • If a gun has a visible hammer, you can be sure that it can be shot single-action by cocking the hammer and pulling the trigger.
  • If a gun has a visible hammer, it might also be able to be shot double-action by just pulling the trigger. That depends on how the gun is designed.
  • A handgun is referred to as “single-action” if, before you pull the trigger, you must cock the hammer manually.
  • A handgun is referred to as “double-action” if it can be shot either “single-action” or “double action.”  You will also see terminology like “DA/SA” for these guns. Most revolvers and many semi-automatics used for concealed carry are “double-action.” On semi-automatics of this type, the only time you can shoot double-action is the first shot in a sequence of shots. After the first shot, the hammer is cocked automatically for the next shot by the action of the slide. So subsequent shots are single-action.
  • A handgun is referred to as “double-action-only” (“DAO”) if you cannot cock a hammer and then shoot it using a single-action trigger pull. For these guns, you will not even see a hammer. Every pull of the trigger cocks the gun and releases the hammer mechanism. Many modern handguns used for concealed carry—both revolvers and semi-automatics—are double-action-only.
  • Generally, the trigger pull is easier in single-action mode than it is in double action mode. This is because the trigger pull is doing less (it is not cocking the hammer).

One of the more confusing aspects of the single-action/double-action discussion is thinking about how this distinction applies to semi-automatics that can shoot single-action—this seems contradictory since you don’t have to cock the this type of gun between shots. For single-action semi-automatics, you do have to cock the gun before it will shoot the first shot. You do that by racking the slide. Once the hammer is cocked, pulling the trigger releases the hammer after the first shot, the slide racks automatically, thereby cocking the hammer for the next shot. Thus, each trigger pull discharges the firearm by releasing the hammer. The explosion of the bullet then forces the slide back, resulting in a cocked hammer for your next shot

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