Part failure/out of spec. Get it to a qualified gun smith ASAP.
Weak spring, bad magazine, dirt, etc..
The shooter must manually cock the hammer back before firing, for every shot.
You hold the hammer, pull the trigger and gently ease the hammer into the firing position. Be sure to point the gun away from any people at all times.
A firing pin that is mounted on/in a hammer
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.
Typically, the hammer strikes the firing pin which may fire a round, if there is a fresh round in the chamber. In older pistols, the hammer can hit the primer directly (the tip of the hammer has the firing pin on the end).
If the decocker is n the fire position, and a round is chambered, the hammer will rise and fall, striking the firing pin. The pin will strike the primer of the cartridge, firing the pistol.
A hammer.
hammer is spring pushed and hits the firing pin to fire the cartridge.
By action of the hammer striking the firing pin, forcing it into the primer.
The hammer is the part that hits the firing pin when you pull the trigger.. this is just an educated guess...
I would use a big hammer.