Glossary of Firearm Terms

The operating mechanism of a firearm excluding the stock and barrel.
Smokeless propellant for small arms made by gelatinizing nitrocellulose and nitroglycerin using heat and pressure.
Barley Corn
Inverted V shape front sight
Battery Gun
A series of three or more muzzle loaded shotgun barrels mounted in a frame on a boat. Used by market hunters and poachers to shoot waterfowl on the water. Steam pipes were often used for this purpose.
A steel blade or spike designed to be attached to the muzzle end of a rifle or shotgun for use in close quarters fighting to stab an enemy combatant.
1. A small metal sphere, usually made of steel that is fired from an air gun.
2. Lead or steel pellets of 0.18 inch diameter made for use in a shotgun.
Black Powder
The first firearm propellant ever used. It came into use in Europe in the 1400's but probably originated in China. It is a mixture of Saltpeter(Potassium Nitrate), Charcoal and Sulfur. It is still in use today for muzzleloading firearms.
See the Blackpowder page for additional information.
A muzzle loading shotgun having a bell shaped muzzle. Contrary to popular opinion, the funnel shape of the muzzle was an aid to loading the gun and not a method to increase the spread of the shot pattern.
Refers to the interior of a gun barrel
Bore Diameter
In a rifled firearm, it is the distance between opposing lands in the barrel. For a smooth bore firearm it is the interior diameter of the gun barrel.
The rear opening of a gun's chamber.
Lead balls used in shotguns for big game hunting. Usually 0.24 inches or larger in diameter.
A groove around the circumference of a bullet in to which the mouth of the case is crimped.
Cap Lock
A muzzleloading rifle or shotgun that uses a percussion cap to ignite the powder charge.
Cellulose Nitrate
The main component of smokeless powder, it is manufactured by reacting nitric acid with cellulose. Also known as Nitrocellulose or gun cotton.
The space in a firearm in which a cartridge is fired.
Another name for a stripper clip
A device for holding multiple cartridges together to allow them to be loaded into a magazine quickly. In many older firearm designs, the clip is retained in the magazine until all the cartridges are expended as is the case with the M1 Garand. A term that is sometimes misused to refer to a detachable magazine
Combination Gun
A firearm having at least one rifled barrel and one shotgun barrel. The most common type is a two barrel over and under rifle shotgun combination although some custom guns may have 3 or more barrels.
A smokeless propellent made of nitrocellulose, nitroglycerin, and mineral jelly extruded into strands which are cut to length for use in small arms ammunition.
Corrosive Ammunition
Loaded cartridges, generally using chlorate based primers which when fired will leave a residue of chemical salts in the barrel. Left in the barrel, humidity in the air can react with these salts causing rust and pitting of the steel.
Cyclic Rate
The number of rounds that an automatc firearm is capable of firing in a given period of time when the trigger is held back. It is usually expressed as rounds per minute.
Term refering to a small easily concealable single or two shot pistol usually of the break open type of action.
A measure of weight once used to measure black powder for shotguns. Equal to 27.3 grains
Combination gun with three barrels. The most commonly encountered configuration is a side by side shotgun with a rifle barrel underneath. The name is derived from the german word for three (drei).
Dry Firing
Pulling the trigger of an unloadled firearm often for the purpose of practicing trigger pull and follow through.
Usually refers to the spring loaded extractors found on some break open shotguns. When the action of these guns is opened the fired cases will pop out of the gun with considerable force making reloading somewhat quicker.
Enbloc Clip
A device for holding multiple cartridges that is loaded with the cartridges into the magazine of a firearm. It is ejected from the firearm when all the cartridges in the clip are expended.
A device on a firearm that engages the rim or extraction groove of a cartridge case and pulls or pushes a cartridge case from the chamber.
Fire Forming
Process used by reloaders to size cartridge cases to fit a particular chamber of a gun by firing the loaded cartridge case in that gun , usually using a reduced powder charge and then only neck sizing the cartridge case.
Flash Hole
Orifice through which the flame of a detonated primer travels to ignite a powder charge in a loaded case.
A fin stabilized steel dart once used by the U.S. Military in place of round shot in shotgun shells and antipersonnel rounds.
The portion of the stock of a long arm that is forward of the receiver. Also known as the fore end or fore stock.
A muzzleloading firearm ignition system. Sparks created by a piece of flint attached to the guns hammer when it the steel priming pan cover. The sparks ignite a small priming charge . The resulting flame is channeled on the main powder charge
Refers to a shot on a paper target outside of the main group. Often occurs on the first shot from a cold and or recently cleaned barrel.
Unrifled section of barrel just ahead of the chamber.
Gallery load
A reduced power rifle load meant to be used in an indoor range or shooting gallery often using reduced weight lead bullets in place of jacketed projectiles with a small charge of fast burning pistol or shotgun powder.
Gas Check
A small metal cup made to fit over the base of a lead bullet to protect it from being melted by the high temperature gases produced by burning propellent when a cartridge is fired. Most commonly used with cast bullets which will be driven to velocities in excess of 1400 feet per second.
A measurement of weight. A grain is 1/7000th to a pound and there are 15.4 grains to a gram. In the united states, projectile and propellent weights are generally expressed in grains while in Europe and they are expressed in grams .
Groove Diameter
The diameter of a rifled barrel from the bottom of one groove to the bottom the groove directly opposite.
Gun Cotton
Nitrocellulose used to manufacture smokeless powder
Hang Fire
A perceptible delay between the trigger on a gun being pulled by the user and the gun actually firing. Most often caused by delayed ignition of the powder charge. Occasionally it may also be due to a mechanical failure.
Headspace is the distance between the head of the cartridge and the closed breech face of a firearm. As a practical matter it is measured by a gauge or gauges inserted in the chamber of a firearm on which the bolt is closed.
1. Rimmed Cartridges - Headspace is measured as the distance from the rim of the cartridge to the breech face.
2. Belted Cartridges - Headspace is measured from the top of the cartridge case belt to the breech face.
3. Rimless Straight wall cartridges - Headspace is measured from the mouth of the cartridge case to the breech face
4. Rimless Bottle neck cartridges - Headspace is measured from the top of the cartridge case shoulder to the breech face.
A series of letters and or numbers stamped or impressed on the base or rim of a cartridge case. Generally this stamping will identify the manufacturer and may include the year of manufacture and or the cartridge designation.
Headstamp List
Iron Sights
Refers to an aiming device on a firearm consisting of an upright post or blade near the muzzle and notch or aperture in behind to allow the shooter to aim the firearm at a target.
Oblong hole produced by an unstabilised bullet striking the target sideways instead of point first.
The raised portion of the interior of a rifled barrel that spiral along its length.
Leaf sight
Rear sight that is hinged at the base so that can be folded down when not in use. Some rifles will have multiple leaf sights each on for a different range.
Brand name powder used primarily to load 22 rimfire cartridges. A mixture of black powder and smokeless powder it was said to produce LESS SMOKE than blackpowder, hence the name.
Long arm
A shoulder fired firearm.
A container used in a firearm to hold ammunition from which cartridges are fed into the chamber by the firearms action
Magazine Cutoff
A device in a firearm that prevents cartridges from feeding from the magazine in order to hold them in reserve, while the user operates the gun as a single shot.
Maximum Effective Range
The greatest distance at which a weapon may be expected to be fired accurately to inflict casualties or damage. Often is dependant on the skill of the user.
Maximum Range
The longest distance that a projectile discharged from a firearm will travel.
A failure to fire after the trigger is pulled. It is generally best to wait at least 30 seconds before clearing the chamber to be sure that it is not a hangfire.
Muzzle Velocity
Speed at which the projectile(s) leave the barrel of a gun. Expressed as feet per second or Meters per second.
A muzzle loading smooth bore military long arm.
A Term that is often used in older firearm literature to refer to a firearms enthusiast or hunter. Also the name of a legendary biblical character in Genesis. He was the King that was supposedly responsible for the construction of the Tower of Babel and is described in the Bible as a mighty hunter.
A chemical compound used to make smokeless powder. It is made by the reaction of Nitric Acid with cellulose containing materials such as cotton.
Paper patching
Once a common practice in the manufacture of Black Powder rifle cartridges. A paper sleeve would be placed on the base of a bullet before being inserted into the cartridge case. The purpose of the paper patch was much the same as the modern gas check. To protect the base of the lead bullets from melting during firing.
Percussion Cap
A small brass cup containing a chemical mixture that detonates when struck that is used to ignite black powder in a muzzle loading firearm.
Early self contained cartridge ignition system invented by Casimir Lefaucheux in 1835. A pin projects from the side of a cartridge case at an angle. When struck by the hammer of the gun it strikes a primer inside the cartridge which ignites the propellant
General term for propellents used in firearms.
1. A small metal cup containing a chemical mixture sensitive to percussion found in the base of a centerfire cartridge. When the firing pin strikes the primer, the primer detonates igniting the powder charge in the cartridge. Primers are generally are made of brass. Boxer primers will have a small triagular piece of metal called an anvil on top of the priming compound.
2. a chemical mixture sensitive to percussion used in a firearm to ignite a powder charge.
Proof Load
A cartridge designed to generate higher that normal operating pressures when fired for the purpose of testing the strength a of a firearm
The testing of a firearm by firing a load that generates much greater chamber pressure than normal for a that firearm. Guns being tested or proofed are usually triggered by some remote means in case the firearm fails and blows up.
Pumpkin Ball
A lead sphere or ball fired from a shotgun having the same diameter as the bore of the shotgun. No longer in common use. Made obsolete by the shotgun slug.
Punt gun
A large bore shotgun mounted on a small boat or punt designed to shoot waterfowl floating on the water. They were used by Market Hunters in the late 19th century and very early 20th century . Some examples are 6 feet or more in length.
A firearm which in the operation of it action it is able extract a fired case from the chamber and then feed a round from an attached magazine into the chamber.
A handgun in which each cartridges or load is contained in a chamber in a rotating cylinder.
Rifles are shouldered fired firearms with barrels having two or more spiral groves in which the bullet will press into causing it to spin. This stabilizes the projectile allowing to strike a target more accurately.
Rim fire
An ignition system where the priming compound is contained in the rim of a thin metal cartridge case. The firing pin strikes the rim to detonate the primer which then ignites the powder charge.
Rook Rifle
A British term for a short range varmint rifle used for shooting crows, rooks,and rabbits. Rook rifles are usually single shot rifles chambered for a low powered pistol type cartridge.
1. A live self contained cartridge.
2. In shotgun target shooting it refers to a series of 25 clay targets shot in trap or skeet
Acronym for the Sporting Arms and Ammunition Manufacturers' Institute.
A common name for the chemical compound Potassium Nitrate (KNO3). May also be spelled as Saltpetre. Saltpeter an oxidizer and a major component of black Powder.
A part of a firearms action that is engaged by the trigger mechanism when the firearm is cocked. When the trigger is pulled the sear is disengaged, which allows the firing pin or hammer to go forward.
Self Loader
See Semiautomatic
A firearms that fires once with each pull of the trigger, it uses the power of the fired cartridge to eject the spent case, recock the firearm and reload the chamber with a new round from the magazine.
Semi smokeless powder
Mixture of smokeless powder and black powder developed with the intention using it in black powder cartridges. Results were often unpredictable.
A Shotgun is a shoulder fired smoothbore firearm which is designed to fire multiple projectiles with each shot. Generally these projectiles are small spheres of lead or steel although some loadings may use a single projectile called a slug. Shotguns generally have a short useful range of less than 60 yards (55 meters) and the muzzle velocity will be between 1100- 1400 fps(335-426 Meter per second) .
Sight Radius
The distance between the front and rear sight of a handgun or rifle.
A strap of leather or cloth attached to a long gun as an aid to carrying the firearm or sometimes used to stabilize the gun when it is being fired.
Smokeless powder
A firearm propellant used in all modern firearms, composed mainly of nitrocellulose with perhaps a small quantity of nitroglycerin.
Snubnose Revolver
A medium caliber double action revolver having a barrel length of 3 inches or less in order to make it more concealable. Most often with fixed iron sights and chambered in 38 Special.
Stacking Rod
Short metal bar or rod projecting from the upper band of a military rifle to allow a group of rifles to be supported by each with the muzzles up and the actions off the ground.
Stripper clip
A device for loading multiple cartridges into a rifle or pistol magazine. The clip of loaded ammunition is placed into the clip guides and the cartridges are pushed out of the clip (stripped) into the firearm's magazine.
Suicide Special
One of a number of small single action rimfire revolvers usually with a spur trigger that were sold in the late 1800's early 1900's
Survival Rifle
A smallbore rifle to be used to hunt game in an emergency situation. Generally characterized by it's light weight and the ability to be easily disassembled and stored as a compact package.
A cartridge utilizing a bullet containing an light generating compound that is ignited when the cartridge is fired. This enables the firer to see where the shots are going and to correct his aim if necessary.
A four barrel combination gun. Usually consisting of two rifle barrels and two shotgun barrels.
An instrument of offensive or defensive combat.
Wildcat Cartridge
a non standard cartridge that is not loaded by any major manufacturer. Usually created for a specific application. Requires the user to load ammunition for a specific firearm.
On a long gun, the thinnest section of the gunstock gripped by the trigger hand of the user.
Zip gun
Crude firearm made of metal tubing or other available materials, usually single shot utilizing a pistol or shotgun cartridge. Usually made illegally.

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