The
percussion cap, introduced around 1830, was the crucial invention that enabled
muzzleloadingA muzzleloader is any firearm into which the projectile and usually the propellant charge is loaded from the muzzle of the gun . This is distinct from the more popular modern designs of breech-loading firearms...
firearms to fire reliably in any weather.
Before this development, firearms used
flintlockFlintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...
ignition systems which produced
flintFlint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...
-on-
steelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
sparks to ignite a pan of priming powder and thereby fire the gun's main powder charge (the flintlock mechanism replaced older ignition systems such as the
matchlockThe matchlock was the first mechanism, or "lock" invented to facilitate the firing of a hand-held firearm. This design removed the need to lower by hand a lit match into the weapon's flash pan and made it possible to have both hands free to keep a firm grip on the weapon at the moment of firing,...
and
wheellockA wheellock, wheel-lock or wheel lock, is a friction-wheel mechanism to cause a spark for firing a firearm. It was the next major development in firearms technology after the matchlock and the first self-igniting firearm. The mechanism is so-called because it uses a rotating steel wheel to provide...
). Flintlocks were prone to misfire in wet weather, and many flintlock firearms were later converted to the more reliable percussion system.
The percussion cap is a small cylinder of
copperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
or
brassBrass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
with one closed end. Inside the closed end is a small amount of a shock-sensitive explosive material such as fulminate of mercury. The percussion cap is placed over a hollow metal "nipple" at the rear end of the gun barrel. Pulling the trigger releases a hammer which strikes the percussion cap and ignites the explosive primer. The flame travels through the hollow nipple to ignite the main powder charge. Percussion caps were, and still are, made in small sizes for pistols and larger sizes for rifles and muskets.
While the metal percussion cap was the most popular and widely-used type of primer, their small size made them difficult to handle under the stress of combat or while riding a horse. Accordingly, several manufacturers developed alternative, "auto-priming" systems. The "
Maynard tape primerThe Maynard tape primer was a system designed by Edward Maynard to allow for more rapid reloading of muskets.-Invention:Muskets in the early 19th century were flintlocks, which had a high rate of misfire and performed poorly in damp and humid weather...
", for example, used a roll of paper "caps" much like today's toy
cap gunA cap gun is a toy gun that creates a loud sound simulating a gunshot and a puff of smoke when the trigger is pulled. Cap guns were originally made of cast iron, but after World War II were made of zinc alloy, and most newer models are made of plastic....
. The Maynard tape primer was fitted to some military firearms used in the
American Civil WarThe American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
. Other disc or pellet-type primers held a supply of tiny fulminate detonator discs in a small magazine. Cocking the hammer automatically advanced a disc into position.
In the 1850s, the percussion cap was first integrated into a metallic
cartridgeA cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
which contained the
bulletA bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...
, powder charge and primer. By the late 1860s, breech-loading metallic cartridges had made the percussion cap system obsolete. Today, reproduction percussion firearms are popular for recreational shooters and percussion caps are still available, though most now use non-corrosive compounds such as
lead styphnateLead styphnate , whose name is derived from styphnic acid, is an explosive used as a component in primer and detonator mixtures for less sensitive secondary explosives....
.
History
The percussion cap replaced the flint, the steel "
frizzenThe frizzen, historically called the steel, is an "L" shaped piece of steel hinged at the rear used in flintlock firearms. It is positioned over the flash pan so as to enclose a small priming charge of black powder next to the flash hole that is drilled through the barrel into where the main...
", and the powder pan of the flint-lock mechanism. It was only generally applied to the British military musket (the
Brown BessBrown Bess is a nickname of uncertain origin for the British Army's Land Pattern Musket and its derivatives. This musket was used in the era of the expansion of the British Empire and acquired symbolic importance at least as significant as its physical importance. It was in use for over a hundred...
) in 1842, a quarter of a century after the invention of percussion powder and after an elaborate government test at Woolwich in 1834. The first percussion firearm produced for the US military was the percussion carbine version (c.1833) of the
M1819 Hall rifleThe M1819 Hall rifle was a single-shot breech loading rifle designed by John Harris Hall, patented on May 21, 1811, and adopted by the U.S. Army in 1819. It used a pivoting chamber breech design and was made with either flint-lock or percussion cap ignition systems. The main years of production...
.
The discovery of
fulminateFulminates are chemical compounds which include the fulminate ion. The fulminate ion, is a pseudohalic ion, acting like a halogen with its charge and reactivity. Due to the instability of the ion, fulminate salts are friction-sensitive explosives. The best known is mercury fulminate, which has...
s was made by
Edward Charles HowardEdward Charles Howard FRS the youngest son of Charles Howard, 11th Duke of Norfolk, was a British chemist who has been described as the first chemical engineer of any eminence....
(1774–1816) in 1800. The invention that made the percussion cap possible using the recently discovered
fulminateFulminates are chemical compounds which include the fulminate ion. The fulminate ion, is a pseudohalic ion, acting like a halogen with its charge and reactivity. Due to the instability of the ion, fulminate salts are friction-sensitive explosives. The best known is mercury fulminate, which has...
s was patented by the Rev.
Alexander John ForsythAlexander John Forsyth was a Scottish Presbyterian clergyman who invented the percussion ignition.Gunsmiths like Joseph Manton invented more reliable forms of ignition, like the tube lock in 1814...
of Belhelvie, Aberdeenshire, Scotland in 1807.
It consisted of priming with a fulminating powder made of fulminate of mercury, chlorate of potash,
sulphurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
, and
charcoalCharcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...
, which was exploded by concussion. It was an invention born of necessity: Rev. Forsyth had noticed that sitting birds would startle when smoke puffed from the powder pan of his
flintlockFlintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...
shotgunA shotgun is a firearm that is usually designed to be fired from the shoulder, which uses the energy of a fixed shell to fire a number of small spherical pellets called shot, or a solid projectile called a slug...
, giving them sufficient warning to escape the shot. His invention of a fulminate-primed firing mechanism deprived the birds of their early warning system, both by avoiding the initial puff of smoke from the flintlock powder pan, as well as shortening the interval between the trigger pull and the shot leaving the muzzle.
Fulminate-primed guns were also less likely to misfire than flintlock guns. However, it was not until after Forsyth's patents expired that the conventional percussion cap system was developed. The percussion cap helped lead to the Self Contained Cartridge, where the bullet is held in by the casing, the casing is filled with gun powder, and a primer (modern day percussion cap), is at the end.
Joshua Shaw- Early life :Shaw was born in Ellesmere Port, England in 1776 and was orphaned at the age of 7. To survive he worked for a local farmer as a bird scarer. During the three years he spent doing this work he discovered his artistic talent and began drawing the animals he encountered...
, an English-born American, is sometimes credited with the development of the first metallic percussion cap in 1814, but his claim remains clouded with controversy as he did not patent the idea until 1822. Shaw's percussion caps used a mixture of fulminate of mercury, chlorate of potash, and ground glass contained in a small metallic cup. Other possible claimants include
François PrélatFrançois Prélat was a French gunsmith and inventor. He is thought to have invented the first fully contained cartridge in 1808, as well as the percussion cap in 1818....
, who patented the percussion cap in 1818,
Joseph MantonJoseph Manton was a much celebrated British gunsmith who was to revolutionise sport shooting, vastly improve the quality of weapons and father the modern artillery shell. Joseph was also a keen sports shooter in his own right and a friend of the celebrated "sportsman" Colonel Peter Hawker.Kings Of...
, Col.
Peter Hawker, and most likely of all, Joseph Egg (nephew of
Durs EggDurs Egg was a Swiss-born British gunmaker, noted for his flintlock pistols and for his company's production of the Ferguson rifle.Egg was apprenticed in Solothurn and Paris before establishing his own business in London in 1772...
).
This invention was gradually improved, and came to be used, first in a steel cap, and then in a copper cap, by various gunmakers and private individuals before coming into general military use nearly thirty years later.
The alteration of the military
flintlockFlintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...
to the percussion musket was easily accomplished by replacing the powder pan and steel "frizzen" with a nipple, and by replacing the cock or hammer which held the flint by a smaller hammer formed with a hollow made to fit around the nipple when released by the trigger. On the nipple was placed the copper cap containing the detonating composition, now made of three parts of chlorate of potash, two of fulminate of mercury and one of powdered glass. The hollow in the hammer contained the fragments of the cap if it fragmented, reducing the risk of injury to the firer's eyes.
The detonating cap, thus invented and adopted, brought about the invention of the modern cartridge case, and rendered possible the general adoption of the breech-loading principle for all varieties of rifles, shotguns and pistols.
Caps are used in cartridges,
grenadeA grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...
s, rocket-propelled grenades, and
rescue flaresA flare, also sometimes called a fusee, is a type of pyrotechnic that produces a brilliant light or intense heat without an explosion. Flares are used for signalling, illumination, or defensive countermeasures in civilian and military applications...
. Percussion caps have also been used as elements in the triggers of
land mineA land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....
s.
See also
- Cap gun
A cap gun is a toy gun that creates a loud sound simulating a gunshot and a puff of smoke when the trigger is pulled. Cap guns were originally made of cast iron, but after World War II were made of zinc alloy, and most newer models are made of plastic....
- Caplock mechanism
The caplock mechanism or "percussion" lock was the successor of the flintlock mechanism in firearm technology, and used a percussion cap struck by the hammer to set off the main charge, rather than using a piece of flint to strike a steel frizzen....
- Internal ballistics
Internal ballistics, a subfield of ballistics, is the study of a projectile's behavior from the time its propellant's igniter is initiated until it exits the gun barrel...
- Tubes and primers for ammunition
Tubes and primers are used to ignite the propellant in projectile weapons.In ancient times various devices were adopted to ignite the charge. Small guns were fired by priming powder poured down the touch hole and ignited by glowing embers or a red-hot iron rod. Later the priming powder was...