The hammer is the term given to the part of a firearm that converts stored up potential energy into the initial source of energy to fire a projectile. It is so called due to the fact that it resembles a workman’s hammer in both form and function; the hammer itself is a metal piece that forcefully rotates about a pivot point. In firearms, the weapon is initially held in a cocked state. When in this state, the hammer has been pulled back and put into a “ready” position with a spring mechanism pulling the hammer so as to cause it to strike when released. This release is connected with the trigger of the weapon, and when the trigger is pulled by the handler of the weapon, the potential energy that is stored in the spring mechanism is released in one quick burst of Kinetic energy.
Once the hammer has been released, it snaps back into its unprimed position and strikes one of various mechanisms to ignite the gunpowder and fire the projectile.
Many firearms in modern times employ a system wherein a hammer comes into contact with a firing pin after it has been released from its primed state by the pull of the trigger. The firing pin acts to linearly transfer the kinetic energy released from the hammer to the primer located in the cartridge itself where chemicals combust, creating a spark, and igniting the gunpowder.
Many modern firearms have the ability by choice of the user or by design to automatically prime the hammer by pulling the trigger. These are often called double action triggers, for they both prime the hammer and release it in the same motion. Other modern weapons still allow the option for the user to manually prime the hammer. In doing so, the user reduces the pull force needed to discharge the weapon, for no additional work must be done to prime the hammer when firing.
Firearms, initially known as “hand cannons”, first became a viable weapon in 1364 through the advancement of chemical technologies to create a gunpowder efficient enough to launch a projectile at high velocities in a hand-held weapon. The issue quickly arose of how to effectively ignite the gunpowder while maintaining the weapon’s aim at the target. Initially, the problem was solved by using a “slow match”: a chemically treated piece of rope that would stay lit for an extended period of time. The smoldering end of the rope would then be manually brought into contact with the gunpowder through a touch hole in the barrel of the weapon when the user was ready to shoot. It proved difficult for the shooter to both keep the weapon aimed and level as well as ignite the gunpowder with the slow match.