Hammer (firearms)

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Hammer uncocked (top). Hammer cocked (bottom).
From the top: striker-fired, linear hammer with free-floating firing pin, hammer-fired with free-floating firing pin, and hammer-fired with integral firing pin Erweiterte Zundsysteme CC BY-SA 4.0 by Grasyl.svg
From the top: striker-fired, linear hammer with free-floating firing pin, hammer-fired with free-floating firing pin, and hammer-fired with integral firing pin

The hammer is a part of a firearm that is used to strike the percussion cap/primer, or a separate firing pin, [1] to ignite the propellant and fire the projectile. It is so called due to the fact that it resembles a hammer in both form and function. The hammer itself is a metal piece that forcefully rotates about a pivot point. [2]


The term tumbler can refer to a part of the hammer or a part mechanically attached to the pivot-point of the hammer, depending on the particular firearm under discussion (see half-cock). According to one source the term tumbler is synonymous with hammer. [3] [4]


Artistic rendition of firing a hand cannon from the Late Medieval era. Illuminated manuscript page from Codex Vindobona. Codex Vindobonensis 3069 38v.jpg
Artistic rendition of firing a hand cannon from the Late Medieval era. Illuminated manuscript page from Codex Vindobona.

Firearms, initially known as "hand cannons",[ citation needed ] first became a viable weapon in 1364[ citation needed ] through the advancement of chemical technologies to create a gunpowder efficient enough to launch a projectile at high speeds 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": [5] 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.[ citation needed ] 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.

The first step to a true hammer system arose shortly after the introduction of the slow match: the matchlock system, introduced in the early 1400s. [5] It acted as an arm, known as a serpentine, that held the lit slow match. When the trigger was pulled, the arm would swing forward from its cocked state (similar to a hammer) via potential energy stored in a spring and bring the lit slow match into contact with the gunpowder.[ citation needed ] The weapon could be utilized with increased accuracy, since the shooter could maintain both hands on the weapon.

Schematic of wheellock system Acciarino ruota.svg
Schematic of wheellock system

By 1509, the wheellock system arose to solve some difficulties of the matchlock system, though it was a very expensive system. The wheellock system used a piece of pyrite attached to an arm called a dogshead [5] that would be brought into contact with a metal wheel that rotated when the trigger was pulled. This would, in turn, shower sparks upon the gunpowder and cause the weapon to discharge. The wheellock represented a major advancement, for it removed the need for maintaining a continually lit slow match which could go out or give off the shooter's location in a time of need. [5]

Following the introduction of the matchlock, the flintlock was introduced in the mid-1600s. [5] The flintlock is similar to the wheellock system, but instead of the hammer mechanism holding pyrite and coming into contact with a moving wheel, the arm (called a cock) held a piece of flint and would be brought forcefully into contact with a steel plate when the trigger was pulled. [5] This would also cause pieces of steel to flake off and ignite due to the friction thereby igniting the gunpowder.[ citation needed ] This method was also far less expensive that the wheellock system. [5]

In 1822, the flintlock system was replaced with what can be called the first hammer system. [5] This arose after Scottish clergyman Reverend Alexander Forsyth discovered the property of mercury fulminate (Hg(ONC)2) to combust when struck.[ citation needed ] Using this discovery, the percussion cap was created. The cap was a small metal cup filled with volatile chemicals placed at the rear of the barrel over a nipple in what was known as the caplock mechanism. A true hammer was cocked via a spring system and held in place until the trigger was pulled to release the hammer. The hammer would then swing forward and strike the percussion cap which would in turn ignite and cause the gunpowder to ignite and fire the weapon.

self-contained cartridge Cartridge, sectional view.JPG
self-contained cartridge

The caplock was in wide use for almost five decades until the widespread introduction of the self-contained cartridge which contained the projectile, gunpowder, and percussion cap all in a single shell that could be easily loaded from the breech of a firearm. [5] The introduction of such a technology led to the implementation of the firing pin and hammer system that is even now still used in certain designs. Whereas the percussion cap in the caplock mechanism was external, the percussion cap in a self-contained cartridge is inside the breech. It is therefore necessary to use a firing pin (a thin rod) to strike the primer through a small penetration in the breech and cause firing. [6]

A Colt Single Action Army at half-cock, showing the external hammer and integral firing pin typical of many revolvers. Half cock.jpg
A Colt Single Action Army at half-cock, showing the external hammer and integral firing pin typical of many revolvers.
A Marlin Model 1894 rifle. The hammer and firing pin are separate components. Marlin 1899 SS Stainless .44 Magnum.jpg
A Marlin Model 1894 rifle. The hammer and firing pin are separate components.
The M16 rifle uses an internal hammer. M16 rifle Firing FM 23-9 Fig 2-7.png
The M16 rifle uses an internal hammer.

An external hammer is one that can be accessed by the operator during use. This allows the hammer to be manually cocked or eased (uncocked) without firing. The hammer is designed with a spur (extension) to facilitate manual operation. An internal hammer cannot be accessed manually during operation. Pistols and shotguns in particular, which have an internal hammer may be referred to as being hammerless. [7]

A striker is a type of firing pin operated by the direct action of a spring rather than by a hammer striking the firing pin. Striker operated firearms lack a hammer.


There are some notable drawbacks to the external hammer system compared to other modern, internal designs. In single-action revolvers, specifically, there is an ever-present danger of accidentally discharging the weapon if the hammer is struck with a shell loaded in the chamber. [8] There is nothing to prevent the hammer from contacting the firing pin and by default the cartridge, in some models, and so the gun will be discharged unintentionally.

An external hammer that could easily catch on clothing Lemathammer.jpg
An external hammer that could easily catch on clothing

Other models do have an internal safety mechanism that prevents contact between the hammer and the firing pin unless the trigger is actually pulled. [8] Even so, many single-action revolver owners choose to carry their revolver with the hammer resting on an empty chamber to minimize the risk of accidental discharge. Additionally, for those who carry their firearm as a personal defense weapon, there is the ever-present worry that an external hammer may catch on a loose article of clothing in an emergency situation, because the hammer protrudes at an angle from the rear of the weapon, and as the owner moves to quickly draw their weapon, the hammer may snag on clothing and cause the loss of seconds in a dangerous situation. Paul B. Weston, an authority on police weapons, called the external a "fish hook" that tended to snag clothing during a fast draw. [9]

Linear hammer

A linear hammer is similar to but differs from a striker in that the hammer is a separate component from the firing pin. When released, a linear hammer, under spring pressure, slides along the bore axis rather than pivoting around a pin placed perpendicular to the bore, as with the more common rotating hammer. The hammer then impacts the rear of the firing pin. Designs such as the Czech vz. 58 and the Chinese QBZ-95 utilize a linear hammer. [10]

See also

Related Research Articles

<span class="mw-page-title-main">Firearm</span> Gun for an individual

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.

<span class="mw-page-title-main">Revolver</span> Firearm with a cylinder holding cartridges

A revolver is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers for firing. Because most revolver models hold up to six cartridges before needing to be reloaded, revolvers are also commonly called six shooters.

<span class="mw-page-title-main">Percussion cap</span> Ignition source in a type of firearm mechanism

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 to the cap lock mechanism or percussion lock system using percussion caps struck by the hammer to set off the gunpowder charge in percussion guns including percussion rifles and cap and ball firearms. Any firearm using a caplock mechanism is a percussion gun. Any long gun with a cap-lock mechanism and rifled barrel is a percussion rifle. Cap and ball describes cap-lock firearms discharging a single bore-diameter spherical bullet with each shot.

A muzzleloader is any firearm into which the projectile and the propellant charge is loaded from the muzzle of the gun. This is distinct from the modern designs of breech-loading firearms. The term "muzzleloader" applies to both rifled and smoothbore type muzzleloaders, and may also refer to the marksman who specializes in the shooting of such firearms. The firing methods, paraphernalia and mechanism further divide both categories as do caliber.

<span class="mw-page-title-main">Action (firearms)</span> Functional mechanism of breech-loading

In firearms terminology, an action is the functional mechanism of a breech-loading firearm that handles the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock.

<span class="mw-page-title-main">Flintlock</span> Firearm with flint-striking ignition

Flintlock is a general term for any firearm that uses a flint-striking 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 itself, also known as the true flintlock, that was introduced in the early 17th century, and gradually replaced earlier firearm-ignition technologies, such as the matchlock, the wheellock, and the earlier flintlock mechanisms such as snaplock and snaphaunce.

<span class="mw-page-title-main">Wheellock</span> Firearm action

A wheellock, wheel-lock, or wheel lock is a friction-wheel mechanism which creates a spark that causes a firearm to fire. It was the next major development in firearms technology after the matchlock and the first self-igniting firearm. Its name is from its rotating steel wheel to provide ignition. Developed in Europe around 1500, it was used alongside the matchlock and later the snaplock (1540s), the snaphance (1560s), and the flintlock.

<span class="mw-page-title-main">Matchlock</span> Firearm mechanism

A matchlock or firelock is a historical type of firearm wherein the gunpowder is ignited by a burning piece of rope that is touched to the gunpowder by a mechanism that the musketeer activates by pulling a lever or trigger with his finger. Before the invention of the matchlock mechanism, the musketeer or an assistant had to apply the match directly to gunpowder by hand, much like a cannon. The matchlock mechanism allowed the musketeer to apply the match himself without losing his concentration.

<span class="mw-page-title-main">Snaphance</span> Type of firearm mechanism

A snaphance or snaphaunce is a type of firearm lock in which a flint struck against a striker plate above a steel pan ignites the priming powder which fires the gun. It is the mechanical progression of the wheellock firing mechanism, and along with the miquelet lock and doglock are predecessors of the flintlock mechanism.

<span class="mw-page-title-main">Pepper-box</span> Multi-barrel firearm

The pepper-box revolver or simply pepperbox is a multiple-barrel firearm, mostly in the form of a handgun, that has three or more gun barrels in a coaxially revolving mechanism. Each barrel holds a single shot, and the shooter can manually rotate the whole barrel assembly to sequentially index each barrel into alignment with the lock or hammer, similar to rotation of a revolver's cylinder.

<span class="mw-page-title-main">Flintlock mechanism</span>

The flintlock mechanism is a type of lock used on muskets, rifles, and pistols from the early 17th to the mid-19th century. It is commonly referred to as a "flintlock". The term is also used for the weapons themselves as a whole, and not just the lock mechanism.

<span class="mw-page-title-main">Lock (firearm)</span>

The lock of a firearm is the mechanism used to initiate firing. It is a historical term, in that it generally refers to such mechanisms used in muzzle-loading and early breech-loading firearms. Side-lock refers to the type of construction, in which the individual components of the mechanism are mounted either side of a single plate. The assembly is then mounted to the stock on the side of the firearm. In modern firearm designs, the mechanism to initiate firing is generally constructed within the frame or receiver of the firearm and is referred to as the firing or trigger mechanism.

<span class="mw-page-title-main">Snaplock</span>

A snaplock is a type of lock for firing a gun or is a gun fired by such a lock.

<span class="mw-page-title-main">Touch hole</span> Small hole near the rear portion (breech) of a cannon or muzzleloading gun

A touch hole, also called a vent, is a small hole at the rear (breech) portion of the barrel of a muzzleloading gun or cannon. The hole provides external access of an ignition spark into the breech chamber of the barrel, either with a slow match (matchlock), a linstock or a flash pan ignited by some type of pyrite- (wheellock) or flint-based gunlock, which will initiate the combustion of the main gunpowder charge. Without touch hole, it would be nearly impossible to ignite the powder because the only otherwise access into the barrel is from the front via the muzzle, which is obturated by the projectile.

<span class="mw-page-title-main">Hammerless</span>

A hammerless firearm is a firearm that lacks an exposed hammer or hammer spur. Although it may not literally lack a hammer, it lacks a hammer that the user can pull directly. One of the disadvantages of an exposed hammer spur is the tendency to get caught on items such as clothing; covering the hammer by removing the spur reduces this tendency.

<span class="mw-page-title-main">Handgun</span> Short-barreled firearm designed to be held and used with one hand

A handgun is a firearm designed to be usable with only one hand. It is distinguished from a long gun which needs to be held by both hands and braced against the shoulder. The two most common types of handguns are revolvers and semi-automatic pistols, although other types such as derringers and machine pistols also see infrequent usage.

The following are terms related to firearms and ammunition topics.

<span class="mw-page-title-main">Superposed load</span>

A superposed load or stacked charge or superimposed load is a method used by various muzzle-loading firearms, from matchlocks to caplocks, as well as newer Metal Storm weapons, to fire multiple shots from a single barrel without reloading. In a sense, superposed load guns were the first automatic firearms, as they fired multiple shots per pull of the trigger.

<span class="mw-page-title-main">Multiple-barrel firearm</span> Type of firearm with more than one barrel

A multiple-barrel firearm is any type of firearm with more than one gun barrel, usually to increase the rate of fire or hit probability and to reduce barrel erosion/overheating.

In firearms and artillery, the primer is the chemical and/or device responsible for initiating the propellant combustion that will push the projectiles out of the gun barrel.


  1. "Principles of Firearms -- Functions -- Firing". rkba.org. Retrieved 2016-04-06.
  2. "Firearms History, Technology & Development: Hammer Fired vs. Striker Fired". Firearms History, Technology & Development. 2015-05-25. Retrieved 2016-04-06.
  3. "Tumbler". Hallowell & Co., Fine Sporting Guns. Retrieved January 5, 2016.
  4. See also: "Sear". Hallowell & Co., Fine Sporting Guns. Retrieved January 5, 2016.
  5. 1 2 3 4 5 6 7 8 9 "NRA Museums". www.nramuseum.org. Retrieved 2016-04-06.
  6. Brown, Edmund G. (2009). Handgun Safety Certificate. West Sacramento, California: California Department of Justice. p. 52.
  7. J-Frame Disassembly.mpg, accessed 10 April 2023. Upon disassembly of a Smith & Wesson hammerless revolver, the internal hammer can be seen.
  8. 1 2 William F. Stevens. John Kvasnicka. Ronald A. Howard Jr. and Marilvn Bergurn*. "Introduction to the Pistol" (PDF). 4-H Shooting Sports Guide. Archived from the original (PDF) on 2018-04-17.
  9. "Hammer Or… "-Less?"Guns Magazine.com | Guns Magazine.com". gunsmagazine.com. 2012. Archived from the original on 2016-04-19. Retrieved 2016-04-06.
  10. Mechanics and Disassembly of the Norinco QBZ-97 / Type 97 NSR Accessed 3 October 2022.