What is the Difference between a Double Action and a Single Action Pistol?

Answer 1

A typical single action pistol or revolver requires that the hammer be manually cocked. In the case of an autoloading pistol, such as the 1911AI .45, the hammer must be cocked before firing the first shot. With a single action revolver, such as the Colt Peacemaker, the hammer must be cocked before each shot.

A double action handgun does not require manual cocking of the hammer- you pull the trigger, and the hammer rises and falls. An example would be the Smith & Wesson Model 10 .38 Special. The hammer may ALSO be cocked manually before a shot.

Some handguns are DAO- double Action Only- the hammer may not be cocked manually- they are fired by pulling the trigger, which will cause the hammer to rise and fall.