A firing pin or striker is a part of the firing mechanism 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 ...

that impacts the

primer Primer may refer to: Arts, entertainment, and media Films * ''Primer'' (film), a 2004 feature film written and directed by Shane Carruth * ''Primer'' (video), a documentary about the funk band Living Colour Literature * Primer (textbook), a te ...

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 acts directly on the firing pin to provide the impact force rather than it being struck by a

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 wi ...

. The terms may also be used for a component of equipment or a device which has a similar function. Such equipment or devices include:

artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during si ...

, munitions and

pyrotechnics Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition ...

Firearms

The typical firing pin is a thin, simple rod with a hardened, rounded tip that strikes and crushes the

. The rounded end ensures the primer is indented rather than pierced (to contain propellant gasses). It sits within a hole through the

breechblock A breechblock (or breech block) is the part of the firearm action that closes the breech of a breech loading weapon (whether small arms or artillery) before or at the moment of firing. It seals the breech and contains the pressure generated by t ...

and is struck by the

when the trigger is "pulled". A light firing-pin spring is often used to keep the firing pin rearward. It may be termed a ''firing-pin return spring'', since it returns it to the unfired position. In

semi-automatic firearm A semi-automatic firearm, also called a self-loading or autoloading firearm ( fully automatic and selective fire firearms are also variations on self-loading firearms), is a repeating firearm whose action mechanism ''automatically'' loads a fol ...

s, this prevents premature firing from the

inertia Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...

of the firing pin as the breech mechanism closes in the reloading part of the firing cycle. Firing pins of this type are often too short to contact the primer when the hammer is resting against it. This is a safety measure to prevent discharge from external forces such as a drop. Firing relies upon the transfer of

momentum In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass ...

from the hammer to give the firing pin sufficient impact energy to cause firing.

Type of cartridge

Animation of a

thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...

The two main types of metallic cartridges used in modern firearms are centerfire and rimfire. In centerfire cartridges, the primer is located in the center of the base of the cartridge. Firing pins for centerfire cartridges usually have a round cross-section and their movement is usually through a hole in the breechblock along the axis of the center of the

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...

's bore. Rimfire cartridges however, must be struck on the base about the rim of the cartridge. While rimfire firearms may use a firing pin with a round cross-section, it is common for them to be flat, with a square or rectangular cross-section and a blunt chisel point. Flat firing pins can be stamped from flat metal stock and usually operate in a slot cut in the breechblock (rather than a hole) that is parallel but offset from the centerline of the barrel. These production methods are generally simpler and reduce production costs. It is generally recommended not to excessively "dry fire" rimfire firearms (ie firing without a chambered round) as it is possible for the firing pin to strike the face of the camber and deform it or damage the firing pin.

Historical cartridges

In 1808 by the Swiss gunsmith Jean Samuel Pauly in association with French gunsmith

François Prélat François Prélat was a Frenchman involved in gunmaking in the early part of the nineteenth century. It is sometimes claimed that he invented the first fully contained cartridge in 1808, as well as the percussion cap in 1818. However most gun his ...

created the first cartridges to integrate a primer and be self-contained. The paper cartridge used a metal base with a through-hole coated in a percussive priming compound. Pauly also developed a breech-loading shotgun for his cartridge, using a firing pin and external hammer. The

Dreyse needle gun Dreyse may refer to: * Johann Nicolaus von Dreyse (1787–1867), German firearms inventor * Hitch Dreyse, a fictional character in ''Attack on Titan'' (''Shingeki no Kyojin'') series who serves in the military police. * Dreyse needle gun, a German ...

of 1836 uses a paper cartridge with a priming as part of a sabot which cradles the projectile and is forward of the propelling charge. The needle-like firing-pin projects from the bolt-face and pierces the cartridge when the breech is closed. On firing, the spring-loaded needle strikes the priming in the sabot. Unlike Pauly's cartridge, which was not widely accepted, Dreyse's rifle was adopted by Prussia as its infantry

service rifle A service rifle (or standard-issue rifle) is a rifle a military issues to regular infantry. In modern militaries, this is typically a versatile and rugged battle rifle, assault rifle, or carbine suitable for use in nearly all environments. M ...

. It was the first military breechloader to use a self-contained cartridge and consequently, the first to employ a firing pin. The

pinfire cartridge A pinfire cartridge is an obsolete type of metallic firearm cartridge in which the priming compound is ignited by striking a small pin which protrudes radially from just above the base of the cartridge. Invented by Frenchman Casimir Lefaucheux i ...

patented in 1835, uses a metallic cartridge with an integrated firing pin located radially near the base of the cartridge. The pin needs to be aligned with a corresponding slot in the chamber; a disadvantage compared with rimfire and center fire cartridges that followed and that are also safer.

Side-lock hammers

Early

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 ...

designs that fired metallic cartridges typically used a side-lock mechanism, with the hammer mounted to one side rather than inline with the axis of the barrel. In the trapdoor

Springfield Model 1865 The Springfield Model 1865 was an early breech-loading rifle manufactured by U.S. Armory in Springfield, Massachusetts. It was a modification of the Springfield Model 1861. It was later replaced with the Springfield Model 1866. Description Durin ...

(and similar) the rear of the firing pin tube within the breechblock is angled away from the centerline of the barrel toward the hammer. The Sharps rifle uses a firing pin block to solve this alignment problem. The block sits within a recess in the breechblock. When struck by the hammer, the whole block is propelled forward. That part of the block with the firing pin sits on the centerline of the barrel and strikes the primer.

Fixed firing pins

Many

revolver A revolver (also called a wheel gun) is a repeating firearm, repeating handgun that has at least one gun barrel, barrel and uses a revolving cylinder (firearms), cylinder containing multiple chamber (firearms), chambers (each holding a single ...

s use a firing pin that is fixed to the hammer. Simple blowback sub-machine guns that fire from the open-bolt position often have a fixed firing pin that protrudes from the face of the bolt. As the bolt fully closes on the breech the primer of the newly chambered round is struck, causing the cartridge to fire. The

Owen Owen may refer to: Origin: The name Owen is of Irish and Welsh origin. Its meanings range from noble, youthful, and well-born. Gender: Owen is historically the masculine form of the name. Popular feminine variations include Eowyn and Owena. ...

and

F1 submachine gun The F1 is a 9x19mm Australian submachine gun manufactured by the Lithgow Small Arms Factory. First issued to Australian troops in July 1963, it replaced the Owen machine carbine. Like the Owen, the F1 had a distinctive top mounted magazine. I ...

are examples that use bolt-face fixed firing-pins. Some mortars use a fixed firing pin mounted in the breech plug. When a mortar round is dropped down the barrel, a primer in the base of the mortar round strikes the firing pin and ignites the propelling charge.

Floating firing pins

In firearms terminology, a floating firing pin is one which is unrestricted by a firing-pin return spring or similar. While it will be captive and unable to simply fall out, either forward or backward, it is otherwise free to slide within these stops. The trapdoor

is an example of a floating firing pin.

Striker

Hammer-operated firing mechanisms use a relatively light firing pin and rely on a transfer of

received from 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 h ...

-loaded

, in the same fashion as a

punch Punch commonly refers to: * Punch (combat), a strike made using the hand closed into a fist * Punch (drink), a wide assortment of drinks, non-alcoholic or alcoholic, generally containing fruit or fruit juice Punch may also refer to: Places * Pu ...

chisel A chisel is a tool with a characteristically shaped cutting edge (such that wood chisels have lent part of their name to a particular grind) of blade on its end, for carving or cutting a hard material such as wood, stone, or metal by hand, s ...

relays the blow from a

mallet A mallet is a tool used for imparting force on another object, often made of rubber or sometimes wood, that is smaller than a maul or beetle, and usually has a relatively large head. The term is descriptive of the overall size and propor ...

. In firearms terminology, a ''striker'' (or striker mechanism) derives the impact force to strike the primer from a spring acting directly upon the 'firing pin' - similar to a

crossbow A crossbow is a ranged weapon using an Elasticity (physics), elastic launching device consisting of a Bow and arrow, bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar ...

, where the striker (firing pin) is like the

crossbow bolt A bolt or quarrel is a dart-like projectile used by crossbows. The name "quarrel" is derived from the French word ''carré'', meaning square, referring to their typically square heads. Although their lengths vary, bolts are typically shorter and ...

(arrow). A striker mechanism is very common in bolt action firearms but not to the exclusion of a hammer-operated mechanisms. It will also be found in other actions where the breechblock reciprocates directly inline with the axis of the barrel. A striker mechanism will consist of the striker spring (firing spring) and the striker. The striker spring is a relatively strong spring sufficient to initiate firing. A typical striker consists of a narrow striking point, a heavier section that acts as a spring guide for the striker spring, a shoulder to restrain the spring, and a catch piece which is engaged by the trigger sear to hold the spring under tension when "cocked" and ready to fire. The striker spring is compressed between the striker's shoulder and the rear of the breechblock. A striker may be assembled from several component; however, the stored energy in the striker spring is transferred directly to the striker and then to the primer without any intermediate transfer of energy or momentum. As striker mechanisms combine both functions of hammer and firing pin in one piece, they are generally considered to be mechanically simpler but are more robust in construction than a typical firing pin. Many small calibre rimfire bolt action rifles and some centerfire automatic weapons (e. g.,

vz. 58 The vz. 58 (or Sa vz. 58) is a 7.62×39mm assault rifle designed and manufactured in Czechoslovakia and accepted into service in the late 1950s as the 7,62 mm samopal vzor 58 ("7.62mm submachine gun model 58"), replacing the vz. 52 self-l ...

) may appear to have a striker-operated firing mechanism but are actually a type of linear hammer. The hammer can be likened to that of a pile driver and is mainly contained within the bolt. It is much like the striker already described except that the "hammer" upon which the firing spring acts and the firing pin are separate units. Confusingly, parts lists will often refer to this type of hammer as a "striker". Striker-fired (or similar) bolt action firearms may be classified as ''cock-on-close'' or ''cock-on-open''.

Cock-on-close

When the breech is opened and retracted rearward, the striker is also carried rearward so that the striker catch passes over the trigger sear. When the bolt is pushed forward to close the breech, the striker catch is held by the trigger sear. The firer must close the bolt with sufficient force to overcome the force exerted by the cocking spring. Notably, the

Lee–Enfield The Lee–Enfield or Enfield is a bolt-action, magazine-fed repeating rifle that served as the main firearm of the military forces of the British Empire and Commonwealth during the first half of the 20th century, and was the British Army's sta ...

and Belgian Mauser cock on closing as do many small calibre rimfire bolt action rifles.

Cock-on-open

The breech of a bolt action rifle is opened by first rotating the bolt handle. In cock-on-open operation, this rotation acts on a cam (similar to the action of a

screw thread A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called ...

) which retracts the striker, compressing the cocking spring and holding it there. When the cocking handle is rotated closed, the cocking cam disengages but the striker is retained in the cocked position by the trigger sear. Introduced in the

Mauser Model 1871 The Mauser Model 1871 adopted as the ''Gewehr'' 71 or ''Infanterie-Gewehr'' 71, or "Infantry Rifle 71" ("I.G.Mod.71" was stamped on the rifles themselves) was the first rifle model in a distinguished line designed and manufactured by Paul Mauser ...

, it significantly reduced the risk of accidental discharge upon closing. The system of operation was widely adopted and is used almost exclusively in modern center-fire rifle designs. The Mauser Gewehr 98, the

Mosin–Nagant The Mosin–Nagant is a five-shot, bolt-action, internal magazine–fed military rifle. Known officially as the 3-line rifle M1891 and informally in Russia and former Soviet Union as Mosin's rifle ( ru , винтовка Мосина, ISO 9: ) ...

and

M1903 Springfield The M1903 Springfield, officially the United States Rifle, Caliber .30-06, Model 1903, is an American five-round magazine-fed, bolt-action service repeating rifle, used primarily during the first half of the 20th century. The M1903 was firs ...

are examples of service rifles using this type of operation.

Other applications

Modern era guns in general (and not just firearms) use a firing pin of some description to initiate firing. Mechanical contact

fuze In military munitions, a fuze (sometimes fuse) is the part of the device that initiates function. In some applications, such as torpedoes, a fuze may be identified by function as the exploder. The relative complexity of even the earliest fuze ...

s in explosive ordinance will employ a firing pin or striker to initiate

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

. Such devices include: artillery projectiles,

aerial bomb An aerial bomb is a type of explosive or incendiary weapon intended to travel through the air on a predictable trajectory. Engineers usually develop such bombs to be dropped from an aircraft. The use of aerial bombs is termed aerial bombing. ...

s and

land mine A land mine is an explosive device concealed under or on the ground and designed to destroy or disable enemy targets, ranging from combatants to vehicles and tanks, as they pass over or near it. Such a device is typically detonated automati ...

s. In landmines, non-metallic firing pins, made from

ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, ...

s for example, may be used to minimise their magnetic signature. The M127A1 signal rocket (and other similar

flare A flare, also sometimes called a fusée, fusee, or bengala in some Latin-speaking countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, ...

s) have a primer in the base of the disposable launch tube. The cap contains a fixed firing-pin inside. The flare is fired by placing the cap over the base and striking it by hand. Hand

grenade A grenade is an explosive weapon typically thrown by hand (also called hand grenade), but can also refer to a shell (explosive projectile) shot from the muzzle of a rifle (as a rifle grenade) or a grenade launcher. A modern hand grenade ge ...

s of the type that use a safety lever (such as the

M26 grenade The M26 is a fragmentation hand grenade developed by the United States military. It entered service around 1952 and was used in combat during the Korean War. Its distinct lemon shape led it to being nicknamed the "lemon grenade" (compare the Ru ...

) use a striker that is similar to the classic spring-loaded

mousetrap A mousetrap is a specialized type of animal trap designed primarily to catch and, usually, kill mice. Mousetraps are usually set in an indoor location where there is a suspected infestation of rodents. Larger traps are designed to catch other s ...

. It is held under tension until the lever is released and then flips over to strike the primer cap. Some

chemical oxygen generator A chemical oxygen generator is a device that releases oxygen via a chemical reaction. The oxygen source is usually an inorganic superoxide, chlorate, or perchlorate; ozonides are a promising group of oxygen sources. The generators are usually ig ...

s use a primer and mousetrap type striker to initiate the chemical reaction.

Images

Image:Grenade F1 ru.svg, Cutaway view of a Russian F1 fragmentation grenade showing firing pin Image:M1-M4 mine cutaway.JPG, Cutaway view of an M4 anti-tank mine showing integral firing pin Image:GYATA-64_cutaway.jpg, Gyata-64 anti-personnel mine Image:PM-79_mine_cutaway.png, PM-79 antipersonnel mine Image:Valmara_59_mine_cutaway.png,

Valmara 59 The Valmara 59 is a large cylindrical Italian bounding anti-personnel mine. It is the first in the "Valmara" family of mines produced by Valsella Meccanotecnica, and was followed by the Valmara 69 and VS-JAP. The mine's body is plastic with a d ...

bounding mine {{Unreferenced, date=May 2021 A bounding mine is an anti-personnel mine designed to be used in open areas. When it is tripped, a small propelling charge launches the body of the mine 3 to 4 feet (90 to 120 cm) into the air, where the main charge ...

Image:MD82_mine_cutaway.JPG,

MD-82 mine The MD-82 is a Vietnamese anti-personnel blast mine, that is broadly similar to the United States M14 mine The M14 mine "Toepopper" is a small ( diameter) anti-personnel land mine first deployed by the United States circa 1955. The M14 mechanis ...

(

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making ...

ese near-copy of the

M14 mine The M14 mine "Toepopper" is a small ( diameter) anti-personnel land mine first deployed by the United States circa 1955. The M14 mechanism uses a belleville spring to flip a firing pin downwards into a stab detonator when pressure is applied. Onc ...

) Image:Russian_-_MUV_pull_fuze.jpg, Military

boobytrap A booby trap is a device or setup that is intended to kill, harm or surprise a human or another animal. It is triggered by the presence or actions of the victim and sometimes has some form of bait designed to lure the victim towards it. The trap m ...

firing device from

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nati ...

(normally connected to a

tripwire A tripwire is a passive triggering mechanism. Typically, a wire or cord is attached to a device for detecting or reacting to physical movement. Military applications Such tripwires may be attached to one or more mines – especially fragme ...

) showing integral striker. The detonator on the end is inserted into a block of explosive e.g.

Semtex Semtex is a general-purpose plastic explosive containing RDX and PETN. It is used in commercial blasting, demolition, and in certain military applications. Semtex was developed and manufactured in Czechoslovakia, originally under the name B ...

Image:Russian_-_VPF_pull_fuze.jpg,

booby trap firing device—pull

: normally connected to a

Image:Russian_MV-5_pressure_fuze.jpg, USSR boobytrap firing device—pressure fuze: victim steps on loose floorboard with fuze concealed underneath. Image:BLU-43B_internal.jpg, Cross-sectional view of a BLU-43 Dragontooth

cluster munition A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller submunitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill personnel and destroy vehic ...

showing firing pin,

detonator A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electr ...

and adjacent

explosive booster {{unreferenced, date=August 2011 An explosive booster is a sensitive explosive charge that acts as a bridge between a (relatively weak) conventional detonator and a low-sensitivity (but typically high-energy) explosive such as TNT. By itself, the ...

charge Image:Type_99_grenade.jpg, Cross-sectional view of a Japanese Type 99 grenade showing firing pin. Image:smine-sensor.jpg, Cross-sectional view of the fuze fitted to a German S-mine Image:M2A4 mine M6A1 fuze.jpg, Cross-sectional view of an American

M2 mine The M2 is a United States bounding anti-personnel mine used during World War II. A number of variants of the mine were produced and although the mine is no longer in US service, it can be found in Cyprus, Iran, Iraq, Korea, Laos, Oman, Rwanda, ...

Image:M14 mine cutaway - internal view.png, Cut-away view of an M14 antipersonnel landmine

References

{{Firearms Firearm components