A gun launches a
projectile at high velocity.
The two most common ways to propel the projectile are using gas produced by a chemical reaction of burning solid propellant such as gunpowder (firearms) and using compressed gas or air (airguns). There are also more exotic designs, such as a Gauss gun which uses magnetic fields, and the Gyrojet which had miniature rockets for ammunition.
Contrary to popular opinion, the process that propels the projectile in a firearm is not an explosion, but rather a very fast burn that releases hot gas. Black powder is only explosive under certain conditions and smokeless powder is not an explosive at all.
Generally, all firearms from the antique cannons to modern day rifles and pistols have the following basic components:
Projectile (bullet)
Barrel
Propellant (powder)
Ignition source (spark or flame)
A most basic gun consists of a barrel closed at one end and an ignition system of some sort. Earliest guns were matchlocks. They used a slow match - a smoldering piece of string. Then came flintlocks which produced sparks from flint striking steel, later to be replaced by percussion caps which used a small amount of chemical that ignited on impact from a spring-loaded hammer. The percussion caps then evolved into cartridge primers that use the same principle. Matchlocks and flintlocks also required the use of a small amount of very fast burning and easy to ignite powder called a priming charge to set off the main charge inside the barrel.
An interesting footnote to this is a modern muzzle-loading rifle made for hunting that uses an electric spark to set off the charge.
Modern guns use either a combination of a hammer and firing pin or a striker. The hammer or the striker are spring-loaded and held back by the sear. Pulling the trigger moves the sear out of the way allowing the hammer to fall on the firing pin or the striker to move forward and to smash the primer of a cartridge which produces a flame to ignite the propellant charge inside the the cartridge case. The burning powder produces gas, which rapidly expands. The pressure from the gas expands the casing slightly making it seal the breech and pushes the projectile out of the case and down the barrel.
Manual repeaters, such as bolt and lever action rifles are cocked through operating the action by hand. Semi-auto guns and auto guns either use some of the gases generated by cartridge, or energy of the recoil to operate the gun automatically.
An interesting exception to the above are the automatic cannons/large caliber machine guns mounted on tanks and airplanes. Some of them use electricity to set off the charge and some use electric or hydraulic motors to work the action rather than recoil or gas energy.
The two most common ways to propel the projectile are using gas produced by a chemical reaction of burning solid propellant such as gunpowder (firearms) and using compressed gas or air (airguns). There are also more exotic designs, such as a Gauss gun which uses magnetic fields, and the Gyrojet which had miniature rockets for ammunition.
Contrary to popular opinion, the process that propels the projectile in a firearm is not an explosion, but rather a very fast burn that releases hot gas. Black powder is only explosive under certain conditions and smokeless powder is not an explosive at all.
Generally, all firearms from the antique cannons to modern day rifles and pistols have the following basic components:
Projectile (bullet)
Barrel
Propellant (powder)
Ignition source (spark or flame)
A most basic gun consists of a barrel closed at one end and an ignition system of some sort. Earliest guns were matchlocks. They used a slow match - a smoldering piece of string. Then came flintlocks which produced sparks from flint striking steel, later to be replaced by percussion caps which used a small amount of chemical that ignited on impact from a spring-loaded hammer. The percussion caps then evolved into cartridge primers that use the same principle. Matchlocks and flintlocks also required the use of a small amount of very fast burning and easy to ignite powder called a priming charge to set off the main charge inside the barrel.
An interesting footnote to this is a modern muzzle-loading rifle made for hunting that uses an electric spark to set off the charge.
Modern guns use either a combination of a hammer and firing pin or a striker. The hammer or the striker are spring-loaded and held back by the sear. Pulling the trigger moves the sear out of the way allowing the hammer to fall on the firing pin or the striker to move forward and to smash the primer of a cartridge which produces a flame to ignite the propellant charge inside the the cartridge case. The burning powder produces gas, which rapidly expands. The pressure from the gas expands the casing slightly making it seal the breech and pushes the projectile out of the case and down the barrel.
Manual repeaters, such as bolt and lever action rifles are cocked through operating the action by hand. Semi-auto guns and auto guns either use some of the gases generated by cartridge, or energy of the recoil to operate the gun automatically.
An interesting exception to the above are the automatic cannons/large caliber machine guns mounted on tanks and airplanes. Some of them use electricity to set off the charge and some use electric or hydraulic motors to work the action rather than recoil or gas energy.
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