Double, Single or DAO?

[Pointer]

I have had confusion with this, so I looked it up on Wikipedia... and if I've got it right;


"Single Action" is when two actions are required to cock AND fire a revolver.

"Double action" is when a single action is required to cock AND fire a revolver.

"Double action ONLY" is when the revolver can only be fired with a single action.

I think I've got it now!

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A single-action revolver requires the hammer to be pulled back by hand before each shot, which also revolves the cylinder. This leaves the trigger with just one "single action" left to perform - releasing the hammer to fire the shot - so the force and distance required to pull the trigger can be minimal. In contrast, with a self-cocking revolver, one long squeeze of the trigger pulls back the hammer and revolves the cylinder then finally fires the shot. They can generally be fired faster than a single-action, but at the cost of reduced accuracy in the hands of most shooters.

Most modern revolvers are "traditional double-action", which means they are able to operate either in single-action or self-cocking mode. The accepted meaning of "double-action" has, confusingly, come to be the same as "self-cocking", so modern revolvers that cannot be pre-cocked are called "double-action-only". These are intended for concealed carry, because the hammer of a traditional design is prone to snagging on clothes when drawn.

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A simple rule of thumb:

A "Single Action" requires only one step to COCK the revolver...

There now, "iz Zot betta o' not so gut?"

 

[montelores]

I believe that the "American Rifleman" had an article concerning this topic in 11/09.

I think that double or single action refers to the trigger system.

S/A: the trigger performs only 1 function.

D/A: the trigger performs 2 functions (cock and fire). Originally, "double-acting". Terminology error.

Monty

 

[Spammy_H]

Single action (SA) means that the trigger only releases a cocked trigger.

Double action (DA) means that pulling the trigger both cocks, and then releases the trigger.

Older revolvers (a/k/a Western revolvers) were SA had to be cocked then fired by pulling the trigger.

Many semiautomatic pistols are SA/DA.

The typical SA/DA semiauto starts in double action mode, then the action of the slide moving back from the first round fired cocks the hammer for successive firings.

You will also find self-defense semiautomatic pistols, as well as revolvers that are DAO, where you cannot cock the hammer manually - each and every round is fired by first cocking the hammer and then releasing it - all by pulling the trigger.

Then you get into striker-fired semiautomatics, which do not have a hammer, but a firing pin and a firing pin spring. Glocks have a "safe action" where the firing pin is partially cocked by the slide, and then fully cocked and then released by the trigger action. Springfield XD's have an "ultra safe action" where the firing pin is fully cocked, and then only released by the trigger. Both the Glock and Springfield XDs, as well as other striker-fired pistols have other safety mechanisms to prevent a negligent discharge (one in which the trigger is not pulled).

A 1911-style semiautomatic pistol is SA, but is meant to be carried "cocked and locked", that is, with the hammer cocked, but with a manual safety engaged. Single action revolvers have no such safety, and are not designed to be safely carried with the hammer cocked, and should never be carried in that manner.

And, of course, there are other variations on the themes presented above, but these are the basic setups for most handguns.

I hope this was a helpful explanation.