![Half cock](https://upload.wikimedia.org/wikipedia/commons/e/eb/Half_cock.jpg)
Half-cock is when the position of the
hammer
A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as w ...
of a
firearm
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes ...
is partially—but not completely—cocked. Many firearms, particularly older firearms, had a notch cut into the hammer allowing half-cock, as this position would neither allow the gun to fire nor permit the hammer-mounted
firing pin
A firing pin or striker is a part of the firing mechanism of a firearm that impacts the primer in the base of a cartridge and causes it to fire. In firearms terminology, a striker is a particular type of firing pin where a compressed spring ...
to rest on a live
percussion cap
The percussion cap or percussion primer, introduced in the early 1820s, is a type of single-use percussion ignition device for muzzle loader firearm locks enabling them to fire reliably in any weather condition. This crucial invention gave rise t ...
or
cartridge
Cartridge may refer to:
Objects
* Cartridge (firearms), a type of modern ammunition
* ROM cartridge, a removable component in an electronic device
* Cartridge (respirator), a type of filter used in respirators
Other uses
* Cartridge (surname), a ...
. The purpose of the half-cock position has variously been used either for loading a firearm, as a
safety
Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to risk management, the control of recognized hazards in order to achieve an acceptable level of risk.
Meanings
There are ...
mechanism, or for both reasons.
The still commonly used English expression of "
going off half-cocked" derives from failing to complete the cocking action, leading to the weapon being unable to fire. This is often used to describe someone acting prematurely, as in the case of one preparing to shoot their weapon without having set the firearm into "full-cock" position.
Early examples
![The Remington-Ryder System No](https://upload.wikimedia.org/wikipedia/commons/d/d9/The_Remington-Ryder_System_No._22.jpg)
Early
flintlock
Flintlock is a general term for any firearm that uses a flint-striking lock (firearm), ignition mechanism, the first of which appeared in Western Europe in the early 16th century. The term may also apply to a particular form of the mechanism its ...
s had required a half-cock position to
prime
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
the
pan, in preparation for firing the firearm, after loading the main chamber. Some other early types of
revolver
A revolver (also called a wheel gun) is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing. Because most revolver models hold up to six roun ...
s, such as the
Colt 1851 Navy Revolver
The Colt Revolving Belt Pistol or Navy Pistol, sometimes erroneously referred to as "Colt Revolving Belt Pistol of Naval Caliber" or "of Navy Caliber" (Naval is heavy gun and Navy Size Caliber was termed later for another Colt model), is a cap and ...
, required the user to place the hammer at half-cock to permit rotation of the
cylinder
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an infin ...
to load the firearm.
On such firearms, the standard practice was not to load all 6 chambers and leave the hammer at half-cock, but, rather, to load only 5 of 6 chambers by standard safety practice, and stow the dropped hammer on an unloaded chamber.
Nonetheless, some users did use the half-cock notch as a very early safety on such revolvers when all 6 chambers were loaded, often to a dangerous and unintended consequence.
Likewise, some early types of repeating
lever action
The toggle-link action used in the iconic Winchester Model 1873 rifle, one of the most famous lever-action firearms
Lever-action is a type of action for repeating firearms that uses a manually operated cocking handle located around the trigger g ...
cartridge
Cartridge may refer to:
Objects
* Cartridge (firearms), a type of modern ammunition
* ROM cartridge, a removable component in an electronic device
* Cartridge (respirator), a type of filter used in respirators
Other uses
* Cartridge (surname), a ...
rifle
A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...
s—such as the
Winchester Model 94
The Winchester Model 1894 rifle (also known as the Winchester 94 or Model 94) is a lever-action repeating rifle that became one of the most famous and popular hunting rifles of all time. It was designed by John Browning in 1894 and originally c ...
rifle—had a half-cock position that ''was'' intended to serve as a safety mechanism, to keep the hammer away from the firing pin while holding the rifle when a round was chambered, such as when in a blind awaiting game to appear.
Although the practice is less common today, the half-cock notch position on such rifles was formerly used by many hunters as a safety when carrying the loaded rifle with a round
chamber
Chamber or the chamber may refer to:
In government and organizations
* Chamber of commerce, an organization of business owners to promote commercial interests
*Legislative chamber, in politics
* Debate chamber, the space or room that houses delib ...
ed while hunting.
The half-cock position of the hammer did not serve a purpose while loading such firearms.
Common examples and breakage
The half-cock notch most commonly worked through insertion of a
spring
Spring(s) may refer to:
Common uses
* Spring (season), a season of the year
* Spring (device), a mechanical device that stores energy
* Spring (hydrology), a natural source of water
* Spring (mathematics), a geometric surface in the shape of a ...
-loaded thin metal plate into a slot cut into the tumbler, the tumbler being variously either part of the hammer or mechanically attached to the pivot-point of the hammer, depending on the particular firearm under discussion. When the tumbler/hammer rotated quickly from full-cock, the spring-loaded metal plate could not engage into the slot cut into the tumbler, and the firearm could fire since the hammer would fully rotate. When the tumbler/hammer rotated slowly from full-cock, such as when engaging the half-cock notch, the metal plate would slide into the slot cut in the tumbler, thereby preventing the hammer/tumbler from rotating fully, hence preventing the hammer from falling and the gun from firing.
In practice, the half-cock notch was often prone to breakage when used as an early safety mechanism, whereby the tumbler would have part of the metal around the slot
shear
Shear may refer to:
Textile production
*Animal shearing, the collection of wool from various species
**Sheep shearing
*The removal of nap during wool cloth production
Science and technology Engineering
*Shear strength (soil), the shear strength ...
away, thereby removing the fragile safety mechanism, and permitting the hammer to fall and the firearm to fire. This could occur from accidentally dropping the loaded firearm onto its half-cocked hammer even once.
References
{{Reflist
Firearm terminology