Yes
A double action firearm requires you to pull back the hammer before you can fire it.
A single action pistol, such as the 191A1 .45 Auto, requires that the hammer be cocked before the first shot. A Double Action pistol does not need to have the hammer cocked- pulling the trigger causes the hammer to rise and fall. Some are DAO- Double Action Only- the hammer cannot BE cocked, and must be fired from a "hammer down" position. These include the Para-Ordnance LDA pistols.
No external hammer to allow single action fire.
If it is a lever action, the model number will be behind the hammer.
Double action
The lock on a muzzle loader consisted of sear, hammer and hammer spring. With some modern guns (a Winchester 94) the hammer/ hammer spring would be a close match. For a striker fired weapon (no outside hammer) it might be the firing pin and spring.
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.
Early revolvers were single action- you had to cock the hammer manually, then pull the trigger. An example would be the Colt Peacemaker. A double action revolver (such as a S&W 357 magnum- Mdl 66) can be fired by pulling the trigger. Trigger pull, by itself, will cause the hammer to rise and fall. OR- the hammer may be cocked, and then the trigger pulled. A "DAO" or double action only, the hammer cannot be cocked, and the gun must be fired by pulling the trigger.
single action pistol means that the hammer has to be cocked back in order to fire. double action means you merely have to pull the trigger back and the gun will fire. some double action guns can be fired single action or double action.
No published data.
If you are asking about the Crosman 3756. Single action is, you pull the trigger and Hammer pulls back and fires. All in one action. OR in double action you pull the hammer back and then pull the trigger to fire the gun. The gun can be fired either way single or double. Target shooters like to use the gun in double action, this removes some of the pressure on the trigger by pulling the hammer back manually, its easier to release the hammer with the trigger already cocked. You can get a better aim in this way. Pulling the trigger in single action causes you pull down with the gun and off your target..
For the first shot, a single action auto, like the 1911A1 .45 auto, must have the hammer cocked manually. A double action auto, like the P38 can be fired by pulling the trigger without cocking the hammer. Trigger pull alone causes hammer to rise and fall.