A touch hole, also known as a cannon vent, is a small hole at the rear (breech) portion 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 stave (wood), staves and bound by wooden or metal hoops. The word vat is often used for large containers ...

of a

muzzleloading Muzzleloading is the shooting sport of firing muzzleloader, muzzleloading guns. Muzzleloading guns, both antique and reproduction, are used for target shooting, hunting, historical re-enactment and historical research. The sport originated in the ...

gun A gun is a device that Propulsion, propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or water cannon, cannons), or gas (e.g. light-gas gun). So ...

cannon A cannon is a large-caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder during th ...

. The hole provides external access of an

ignition Ignition may refer to: Science and technology * Firelighting, the human act of creating a fire for warmth, cooking and other uses * Combustion, an exothermic chemical reaction between a fuel and an oxidant * Fusion ignition, the point at which a ...

spark into the breech chamber of the barrel (where the combustion of the

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicle ...

occurs), either with a

slow match Slow match, also called match cord, is the slow-burning cord or twine fuse used by early gunpowder musketeers, artillerymen, and soldiers to ignite matchlock muskets, cannons, shells, and petards. Slow matches were most suitable for use ar ...

(

matchlock A matchlock or firelock is a historical type of firearm wherein the gunpowder is ignited by a burning piece of flammable cord or twine that is in contact with the gunpowder through a mechanism that the musketeer activates by pulling a lever or Tri ...

), a

linstock A linstock (also called a lintstock) is a staff with a fork at one end to hold a lighted slow match. The name was adapted from the Dutch ''lontstok'', "match stick". Linstocks were used for discharging cannons in the early days of artillery; th ...

or a

flash pan The flash pan or priming pan is a small receptacle for priming powder, found next to the touch hole on muzzle-loading guns. Flash pans are found on gonnes, matchlocks, wheellocks, snaplocks, snaphances, and flintlocks. Development The flash ...

ignited by some type of

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

- (

wheellock 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 ...

) or

flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start ...

-based gunlock (

snaplock A snaplock is a type of lock for firing a gun or is a gun fired by such a lock. A snaplock ignites the (usually muzzle-loading) weapon's propellant by means of sparks produced when a spring-powered cock strikes a flint down on to a piece of hard ...

snaphaunce Swedish snaphance guns from the mid 17th century 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 progressi ...

, and

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 ...

), which will initiate the

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

of the main

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

charge Charge or charged may refer to: Arts, entertainment, and media Films * ''Charge, Zero Emissions/Maximum Speed'', a 2011 documentary Music * ''Charge'' (David Ford album) * ''Charge'' (Machel Montano album) * '' Charge!!'', an album by The Aqu ...

. 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

obturate Obturation is the necessary barrel blockage or fit in a firearm or airgun created by a deformed soft projectile. A bullet or pellet made of soft material and often with a concave base will flare under the heat and pressure of firing, filling the ...

d by the

projectile A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found ...

. In the later

caplock The percussion cap, percussion primer, or caplock, 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. Its invention gave ...

firearms, the ignition sparks are generated by a shock-sensitive

percussion cap The percussion cap, percussion primer, or caplock, 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. Its invention gave ...

placed over a conical "nipple", which has a hollow

conduit Conduit may refer to: Engineering systems * Conduit (fluid conveyance), a pipe suitable for carrying either open-channel or pressurized liquids * Electrical conduit, a protective cover, tube or piping system for electric cables * Conduit cur ...

known as the flash channel, that leads into the barrel and serves the same function as the touch hole. In modern

breechloading A breechloader is a firearm in which the user loads the ammunition from the breech end of the barrel (i.e., from the rearward, open end of the gun's barrel), as opposed to a muzzleloader, in which the user loads the ammunition from the ( muzzle ...

firearms, the propellant charge is packaged inside a cartridge, which has a modified percussion cap (

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 ...

) seated in a cavity at the back end of the cartridge case. Between the primer pocket and the case chamber are one or more apertures known as flash holes, which serves functionally as a touch hole ''inside'' the cartridge. In

artillery Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...

, priming powder, a

fuse Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hydraulic systems to protec ...

, squib, or friction igniter is inserted into the touch hole to ensure ignition of the charge. The ignition might be achieved via striking or electrically.

Spiking the guns

''Spiking a gun'' was a method of temporarily disabling a

by hammering a barbed steel spike into the touch hole; this could be removed only with great difficulty. If a special spike was unavailable, spiking could be done by driving a

bayonet A bayonet (from Old French , now spelt ) is a -4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ... , now spelt ) is a knife, dagger">knife">-4; we might wonder whethe ...

into the touch-hole and breaking it off, to leave the blade's tip embedded. Guns could also be rendered useless by burning their wooden

carriage A carriage is a two- or four-wheeled horse-drawn vehicle for passengers. In Europe they were a common mode of transport for the wealthy during the Roman Empire, and then again from around 1600 until they were replaced by the motor car around 1 ...

s or blowing off their

trunnion A trunnion () is a cylinder, cylindrical Boss (engineering), protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development. In mechanical engineering (see the Trunnion#Trunnion bearin ...

s. Count Friedrich Wilhelm von Bismarck, in his ''Lectures on the Tactics of Cavalry'', recommended that every cavalry soldier carry the equipment needed to spike guns if an encounter with enemy artillery was expected. If a cannon were in danger of being captured by the enemy, its crew would spike the gun to prevent it from being used against them. Captured guns would be spiked if they could not be hauled away and the gun's recapture seemed likely.

References

{{reflist Firearm components Articles containing video clips