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Percussion cap

Single-shot caplock pistol used to assassinate

Abraham Lincoln. This type of small handgun is

known as a Derringer.

The percussion cap, introduced circa 1820, was the crucial invention

that enabled muzzleloading firearms to fire reliably in any weather.

Before this development, firearms used flintlock ignition systemswhich produced flint-on-steel 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 matchlock and

wheellock). 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 copper or brass 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 smallsize 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 primer", for example, used a roll of paper "caps" much like

today's toy cap gun. The Maynard tape primer was fitted to some military firearms used in the American Civil War.

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 cartridge which contained the bullet, powdercharge 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 styphnate.

History

Inverted percussion pistol, 9.5mm; made by

gunsmith Correvon, Morges, 1854. On display at

Morges military museum.

The percussion cap replaced the flint, the steel "frizzen", and the

powder pan of the flint-lock mechanism. It was only generally applied

to the British military musket (the Brown Bess) 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 rifle.

The discovery of fulminates was made by Edward Charles Howard

(17741816) in 1800.[1]

The invention that made the percussion cap

possible using the recently discovered fulminates was patented by the

Rev. Alexander John Forsyth of Belhelvie, Aberdeenshire, Scotland in

1807.

It consisted of priming with a fulminating powder made of fulminate of mercury, chlorate of potash, sulphur, and

charcoal, which was ignited by concussion.[2] 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 flintlock shotgun, giving them sufficient

http://en.wikipedia.org/w/index.php?title=Flintlockhttp://en.wikipedia.org/w/index.php?title=Shotgunhttp://en.wikipedia.org/w/index.php?title=Shotgunhttp://en.wikipedia.org/w/index.php?title=Flintlockhttp://en.wikipedia.org/w/index.php?title=Charcoalhttp://en.wikipedia.org/w/index.php?title=Sulfurhttp://en.wikipedia.org/w/index.php?title=Chlorate_of_potashhttp://en.wikipedia.org/w/index.php?title=Fulminate_of_mercuryhttp://en.wikipedia.org/w/index.php?title=Alexander_John_Forsythhttp://en.wikipedia.org/w/index.php?title=Reverendhttp://en.wikipedia.org/w/index.php?title=Fulminatehttp://en.wikipedia.org/w/index.php?title=Edward_Charles_Howardhttp://en.wikipedia.org/w/index.php?title=Fulminatehttp://en.wikipedia.org/w/index.php?title=M1819_Hall_riflehttp://en.wikipedia.org/w/index.php?title=Brown_Besshttp://en.wikipedia.org/w/index.php?title=Frizzenhttp://en.wikipedia.org/w/index.php?title=File%3APistolet_%C3%A0_percussion_invers%C3%A9e_IMG_3074.jpghttp://en.wikipedia.org/w/index.php?title=Morgeshttp://en.wikipedia.org/w/index.php?title=Lead_styphnatehttp://en.wikipedia.org/w/index.php?title=Primer_%28firearm%29http://en.wikipedia.org/w/index.php?title=Bullethttp://en.wikipedia.org/w/index.php?title=Cartridge_%28firearms%29http://en.wikipedia.org/w/index.php?title=American_Civil_Warhttp://en.wikipedia.org/w/index.php?title=Cap_gunhttp://en.wikipedia.org/w/index.php?title=Maynard_tape_primerhttp://en.wikipedia.org/w/index.php?title=Fulminate_of_mercuryhttp://en.wikipedia.org/w/index.php?title=Explosive_material%23Primary_explosivehttp://en.wikipedia.org/w/index.php?title=Brasshttp://en.wikipedia.org/w/index.php?title=Copperhttp://en.wikipedia.org/w/index.php?title=Wheellockhttp://en.wikipedia.org/w/index.php?title=Matchlockhttp://en.wikipedia.org/w/index.php?title=Steelhttp://en.wikipedia.org/w/index.php?title=Flinthttp://en.wikipedia.org/w/index.php?title=Flintlockhttp://en.wikipedia.org/w/index.php?title=Muzzleloaderhttp://en.wikipedia.org/w/index.php?title=File%3ABooth_deringer.jpghttp://en.wikipedia.org/w/index.php?title=Derringerhttp://en.wikipedia.org/w/index.php?title=Abraham_Lincolnhttp://en.wikipedia.org/w/index.php?title=Caplock

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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 gunpowder, and a primer isat the end.

Joshua Shaw, 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 Franois Prlat, who patented the percussion cap in 1818, Joseph

Manton, Col. Peter Hawker, and most likely of all, Joseph Egg (nephew of Durs Egg).

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 flintlock 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, grenades, rocket-propelled grenades, and rescue flares. Percussion caps are also used in

land mine fuzes, boobytrap firing devices and anti-handling devices.

Booby-trap Firing Devices

As a rule, most purpose-made military booby-trap firing devices contain some form of spring-loaded firing pin

designed to strike a percussion cap connected to a detonator at one end. The detonator is inserted into an explosive

charge e.g. C4 or a TNT. Triggering the booby-trap (e.g. by pulling on a trip-wire) releases the cocked firing pin

which flips forward to strike the percussion cap, firing both it and the attached detonator. The resulting shock-wave

from the detonator sets off the main explosive charge.

USSR booby trap firing device - pull fuze:

normally connected to a tripwire. Percussion

cap is clearly labelled

Alternative design of USSR booby trap firing

device - pull fuze: normally connected to

tripwire. Percussion cap is clearly labelled

USSR boobytrap firing device - pressure

fuze: victim steps on loose floorboard

with fuze concealed underneath

http://en.wikipedia.org/w/index.php?title=File%3ARussian_MV-5_pressure_fuze.jpghttp://en.wikipedia.org/w/index.php?title=File%3ARussian_-_MUV_pull_fuze.jpghttp://en.wikipedia.org/w/index.php?title=File%3ARussian_-_VPF_pull_fuze.jpghttp://en.wikipedia.org/w/index.php?title=Tripwirehttp://en.wikipedia.org/w/index.php?title=Fuzehttp://en.wikipedia.org/w/index.php?title=USSRhttp://en.wikipedia.org/w/index.php?title=Firing_pinhttp://en.wikipedia.org/w/index.php?title=Trinitrotoluenehttp://en.wikipedia.org/w/index.php?title=C4_explosivehttp://en.wikipedia.org/w/index.php?title=Detonatorhttp://en.wikipedia.org/w/index.php?title=Firing_pinhttp://en.wikipedia.org/w/index.php?title=Spring-loadedhttp://en.wikipedia.org/w/index.php?title=Booby-traphttp://en.wikipedia.org/w/index.php?title=Anti-handling_devicehttp://en.wikipedia.org/w/index.php?title=Boobytraphttp://en.wikipedia.org/w/index.php?title=Fuzehttp://en.wikipedia.org/w/index.php?title=Land_minehttp://en.wikipedia.org/w/index.php?title=Flare_%28pyrotechnic%29http://en.wikipedia.org/w/index.php?title=Rocket-propelled_grenadehttp://en.wikipedia.org/w/index.php?title=Grenadehttp://en.wikipedia.org/w/index.php?title=Cartridge_%28weaponry%29http://en.wikipedia.org/w/index.php?title=Cartridge_%28weaponry%29http://en.wikipedia.org/w/index.php?title=Flintlockhttp://en.wikipedia.org/w/index.php?title=Durs_Egghttp://en.wikipedia.org/w/index.php?title=Joseph_Egghttp://en.wikipedia.org/w/index.php?title=Peter_Hawkerhttp://en.wikipedia.org/w/index.php?title=Joseph_Mantonhttp://en.wikipedia.org/w/index.php?title=Joseph_Mantonhttp://en.wikipedia.org/w/index.php?title=Fran%C3%A7ois_Pr%C3%A9lathttp://en.wikipedia.org/w/index.php?title=Joshua_Shawhttp://en.wikipedia.org/w/index.php?title=Primer_%28firearm%29

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References

[1] Edward Charles Howard (http://www.npg. org. uk/live/search/person. asp?LinkID=mp02292) at National Portrait Gallery

[2] Samuel Parkes, The chemical catechism : with notes, illustrations, and experiments, New York : Collins and Co., 1818, page 494 (page 494

online, see LVI. A New Kind of Gunpowder.) (http://books. google. de/books?id=qQ0NAAAAYAAJ&dq=related:ISBN0714611476&

as_brr=3& pg=PA494#v=onepage& q& f=false)

Winant, L. (1956).Early percussion firearms. Bonanza Books

http://books.google.de/books?id=qQ0NAAAAYAAJ&dq=related%3AISBN0714611476&as_brr=3&pg=PA494#v=onepage&q&f=falsehttp://books.google.de/books?id=qQ0NAAAAYAAJ&dq=related%3AISBN0714611476&as_brr=3&pg=PA494#v=onepage&q&f=falsehttp://en.wikipedia.org/w/index.php?title=Samuel_Parkes_%28chemist%29http://www.npg.org.uk/live/search/person.asp?LinkID=mp02292

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Article Sources and Contributors 4

Article Sources and ContributorsPercussion cap Source: http://en.wikipedia.org/w/index.php?oldid=535804543 Contributors: 4C, Aldis90, AliveFreeHappy, Andre Engels, Antonio Lopez, Asams10, Benvenuto, BigPadge94,

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Image Sources, Licenses and ContributorsImage:Booth deringer.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Booth_deringer.jpg License: Public Domain Contributors: Original uploader was Fluzwup at en.wikipedia

File:Pistolet percussion inverse IMG 3074.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Pistolet__percussion_inverse_IMG_3074.jpgLicense: Creative Commons

Attribution-Sharealike 2.0 Contributors: Rama

Image:Russian_-_VPF_pull_fuze.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Russian_-_VPF_pull_fuze.jpgLicense: Public Domain Contributors: US Gov.

Image:Russian_-_MUV_pull_fuze.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Russian_-_MUV_pull_fuze.jpgLicense: Public Domain Contributors: US Gov.

Image:Russian_MV-5_pressure_fuze.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Russian_MV-5_pressure_fuze.jpg License: Public Domain Contributors: US Gov.

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