Action--The action of a gun is generally the sum of its moving parts. 

Action Job--An action job is where a skilled person removes the components of the firearm and polished the parts to reduce friction.  The springs are often replaced to lighten the trigger pull for competition or hunting.

Accurize--To make a gun more accurate by improving the fit of existing parts or replacing parts with those of a better quality.

Back-strap--The back-strap of a revolver is the place the grips attach at the rear of the frame.  It usually is partially exposed and provides a place for the mainspring.  Back-straps may be an extension of the frame or made to attach with screws.

Barrel to Cylinder Gap--This is the distance in a revolver between the rear of the barrel and the face of the cylinder.  If the gap is too small, the cylinder may bind as combustion byproducts build up and close the gap.  If the gap is too large, the gun will blow excessive amounts of combustion gas out through the gap and will bullets will loose velocity and cause gas cutting.

Barrel Wedge--The barrel wedge is found on the 1836-1872 model colt revolvers and many of their copies.  It is used to hold the barrel to the cylinder arbor.  It is tapped out to allow the barrel to be removed for cleaning and is tapped back into place to secure the barrel.

Bolt--The bolt is usually found in rifles and is the part of the rifle's action that moves in and out of the breech and serves as the rear of the firing chamber.  In lever action rifles, the bolt is moved out of the chamber through the action of the lever.  It removes the spent cartridge from the firing chamber and discards it.  It also picks up a new cartridge from the magazine and pushes it into the breech.  The bolt is locked into place and helps retain the cartridge and combustion pressure. 

Bore Scope-- Is an optical device that can be fed down into the bore of a firearm to visually inspect the insides of the bore.

Breech--The breech of a gun is located at the end of the barrel and is where the load is loaded.  This is where the powder and ball are found on a loaded cap and ball firearm, and where the cartridge is found in a cartridge firearm. 

Breechface--The part of a revolver frame where the firing pin is located, or has a window  to allow a hammer-mounted firing pin reach the primer.

Buckhorn Sight--Is a special rear sight that is shaped like a set of animal horns after which it is named.  The sights allow for good visibility while allowing a precise target alignment. 

Buttstock--The buttstock is the section of stock that attaches to the receiver, usually of a shotgun or rifle, and extends rearward to the shooter's shoulder.

Buttplate--The buttplate is found on the end of the buttstock where the stock meets the shooter's shoulder.  Some are curved, some are flat, while others may be padded.

Caliber--The measurement of the firearm bore size.

Cartridge, centerfire--A cartridge design that uses a replaceable primer pressed into the center of the base of the casing to detonate the explosive or propellant powder.  The gun's firing pin detonates the primer by striking it in the center of the base of the cartridge.

Cartridge, rimfire--A cartridge design that has the impact sensitive priming materials distributed around the inside rim of the base.  The gun's firing pin detonates the primer material by striking the base of the casing near the outside rim of the cartridge.

Cartridge, Metallic--A cartridge is made up of a casing or shell, primer, powder, and projectile (bullet).

Cartridge, paper--A paper cartridge is made up of a ball and powder contained in a rolled paper tube.  The shooter tears off the end of the paper and pours the powder into the gun.  The shooter then moistens the paper and uses it as a patch between the cylinder/barrel and the bullet.

Caustic Bluing--A bluing process that uses a caustic solution at high temperature to oxidize the steel on the gun and turn it a deep blue/black.  This process is believed to have been developed in Germany sometime between 1920 and 1940.

Chamber--The recess in the cylinder or barrel where the cartridge is held for firing.

Choke--A constriction in the barrel of a shotgun that changes the shot pattern to provide either a narrower or wider pattern of shot, depending on the intended application.

Chrome--A hard plating of chromium that is applied to the firearm to provide a very tough and corrosion resistant finish.

Color Case Hardening--A process of adding carbon to the outer surface of steel while also providing an attractive multi-color finish in the steel.

Crown--Is a beveled shaping of the muzzle of the barrel of a firearm that is intended to allow the bullet to leave the barrel with a very even release.

Cylinder--The cylinder is located between the barrel and the standing breech on a revolver.  The cylinder contains the chambers that hold the ammunition and contains the blast of the powder.

Cylinder Gap-- The space between the cylinder and the barrel.

Cylinder Lock Bolt--The cylinder lock bolt is found in the frame of a revolver under the cylinder.  It usually rises from the frame and engages a mortise in the cylinder to lock the cylinder in proper alignment with the barrel.

Cylinder Pin--The Cylinder Pin passes through the center of the cylinder and acts as a pivot hinge.   The cylinder is removed by sliding the cylinder pin forward until it will allow the cylinder to be slid from the frame of the gun.

Cylinder axle--The same as the cylinder pin.

Desiccant--Is a chemical that absorbs moisture from the air in order to protect parts in the environment from corrosion.

Double action--Is a trigger action that allows the pull of the trigger to also cock the hammer.

Draw Filing--Usually used to create the flat sides of an octagonal barrel.  The file is drawn down the length of the barrel in a way that it provides a reasonably flat side without waves.  The file is held at an angle that is close to being parallel to the barrel.

Drop-- The distance between the top of the comb of a rifle stock and the center line of the barrel.  The drop determines the amount of climb the rifle exhibits during recoil and also affects how much the shooter must lower his head in order to properly use the sights.

Dummy Cartridge--Is a cartridge that meets the ammunition size requirements, but is not capable of being fired.  They are used by shooters for practicing loading techniques and are used by gunsmiths to safely test the action of a gun.

Ejector--A part of the action of a firearm that throws the empty cartridge clear of the weapon.  Single action revolvers usually have an ejector/extractor rod that is used to push the cartridge back through the loading port.  Double action revolvers usually have a star built into the end of the chamber that ejects/extracts all cartridges at the same time.

Ejector Tube--Is usually found running down the barrel on the right side of a single action revolver.  It houses the ejector rod.

Elevation-- The vertical measurement of sighting a firearm to the target.  Elevation adjustments are made by raising or lowering the rear sight.  They are occasionally made by raising or lowering a front sight.

Engraving--An artistic carving in the metal of a firearm that often follows a floral or hunting pattern.  When done well, it can significantly increase the attractiveness of the gun and its value.

End play-- The amount of front-rear movement of the cylinder in a revolver.  See End Shake.

Epoxy-- A bonding agent that is mixed with a catalyst to harden through an endothermic reaction between the two materials.  Epoxy has strong adhesive qualities and remains very stable.  It is very strong when mixed with a reinforcing material such as glass fibers.

Extractor--This is the mechanism that pushes the cartridge out of the chamber, usually after the cartridge has been fired.  Double barrel shotguns often have extractors to push the empty hull out so the shooter can pull the empty hulls out. 

End Shake--This is a measurement of the amount of play that is found in the cylinder of a revolver.  It is checked by moving the cylinder forward and rearward on the cylinder axle.  I measure it by measuring the cylinder to barrel gap with the cylinder pushed forward and measure it again with the cylinder pulled to the rear.  I then subtract the smaller gap measurement from the larger to come up with the end-shake measurement.

Fanning--Fanning is the art of rapidly shooting a single action revolver by holding the trigger in the pulled position and slapping the hammer back with the bottom of the free hand.  This is often seen in western movies and is very hard on the gun.  It can be dangerous as the forces might push the cocked or partially cocked firearm out of the shooter's hand.

Fire Lapping-- A process of breaking in a new barrel that involves using an abrasive past on the bullet in order to improve imperfections in the barrel.

Firing Pin--The firing pin is a piece of steel that it either in the frame of the gun or mounted directly to the hammer.  It is used to dent the cartridge primer in a way that detonates the impact sensitive explosive.

Flutes-- A series of groves or troughs cut in the cylinder of a revolver in order to reduce weight.  The flutes are on the outside of the cylinder and run parallel to the chamber.

Forcing Cone, Revolvers--The forcing cone is usually found on revolvers at the rear of the barrel.  It provides a slight funnel at the rear of the barrel compress and align the projectile as it transitions from the cylinder to the rifling grooves of the barrel.

Forcing Cone, Shotguns--The forcing cone on a shotgun is located forward of the chamber in front of the hull and provides a place for the open end of the hull to unfold and then narrows to bring the shot to the contour of the barrel.

Forearm--The portion of wood that is attached under the barrel of a rifle or shotgun.  It is helpful in improving the grip on the gun and isolates the shooter's hand from any heat coming from the barrel, especially useful when shooting blackpowder.

Gas Cutting--Gas Cutting occurs when the barrel to cylinder gap is too large and hot combustion gasses create a hot jet that erodes the rear of the barrel, the front of the cylinder, or any other surface affected by the hot gasses.

Gas Ring--The gas ring is usually a bushing or flange on the front of the cylinder.  It usually juts forward a little around the cylinder axle and prevents the cylinder axle hole from being in the same plane as the barrel/cylinder gap.  This prevents hot gasses and powder residue from entering directly into the cylinder axle and fouling the action.

Glass Bedding-- Is the use if an epoxy and fillers to fill in imperfections in the stock.  The purpose is to use a pliable material to fill in the voids between the receiver and the stock with a very stable material that forms to the exact dimensions of the receiver.

Hammer--The hammer on a revolver or lever action rifle is located at the rear of the receiver or frame at some point behind the cartridge or percussion cap.  The hammer may be hidden on some guns like shotguns and automatic pistols.  The trigger releases the cocked hammer, which causes it to accelerate forward and strike the firing pin or cartridge primer.  This fires the cartridge.

Hand-- The lever in a revolver that engages the star at the rear of the cylinder.  Movement of the hand is controlled by either the trigger or hammer and serves to advance the cylinder to the next position.

Headspace--Headspace is a measurement of the distance between the rear of a cartridge and the bolt or recoil shield.  It is the amount of distance the cartridge can move during the firing of the gun.  Headspace can be measured on a revolver using a feeler gauge, but go no-go gauges are used to determine if the headspace is acceptable on firearms that do not allow access to this area.

Lever Action Rifle--The lever action rifle is one with an actuating lever connected to the breech bolt. When cycled, the breech bolt is retracted from the breach, the cartridge is ejected, and a new cartridge is fed into the breech.

Loading Gate-- Is found on the right side of single action revolvers and is opened in order to gain access to the loading port for loading cartridges into the chambers.

Loading Lever--The loading lever is usually found mounted under the barrel on a cap and ball revolver.  Not all have them, but they are used to force the lead ball into the cylinder while loading.

Loading Port--Is a recess on the right side of the recoil shield on a single action revolver.  It provides the necessary clearance for lining the cartridges up with a chamber in the cylinder for loading and unloading.

Lock, Flint--A flint lock is an older design of blackpowder ignition that uses a piece of flint that is forced against a steel plate (frizzen) when the trigger is pulled.  The flint showers sparks into a small pan that is filled with flash powder.  The flash powder ignites and the burning of the flash powder ignites the blackpowder in the breech through the touchhole.

Lock, Cap--A more modern ignition system that uses an impact sensitive percussion cap to create sparks that are focused through a nipple and into the breech of the blackpowder firearm.  The sparks ignite the gunpowder, which fires the weapon.

Magazine-- Is the place in a firearm where cartridges are stored prior to being moved into the breech.  Common magazines include a tubular magazine often found under the barrel of a lever action rifle.

Mainspring--The mainspring or hammer spring, is the spring that powers the hammer.

Mule Ear-- Generally refers to a shotgun that is equipped with external hammers that must be cocked before the gun may be fired.

Nipple--Nipples are found on percussion firearms and hold the percussion cap.  Nipples will eventually peen down from the pounding of the hammer and must be reshaped or replaced.  The nipple provides a constriction that allows the sparks into the chamber to ignite the powder, but serve to limit combustion gas from escaping back toward the shooter.

Percussion Revolver--The percussion revolver is an early design the allows powder to be poured into the cylinder followed by a round lead ball.  The lead ball is pressed into the barrel end of the chamber by using a lever ram usually attached to the gun.  A percussion cap is placed on the nipples on the rear of the chambers and the gun is ready to fire.

Power Factor--Is a measurement of total power associated with a cartridge load.  It is usually the weight of the bullet times the muzzle velocity.

Ramrod--The ramrod is a long rod that is usually found slid into a hole that is under the barrel of a muzzle-loading firearm.  It is used to force the bullet down the barrel, into the breech, and against the powder charge.  Most are wood with metal ends, but newer ones are made of various plastics.

Ratchet--The machined spikes or recesses at the rear of a revolver cylinder that is pushed by the hand in order to move the cylinder.  Sometimes also called the Star.

Rebounding Hammer--A rebounding hammer is on that strikes the firing pin and then rebounds back to a natural balance point that appears to be partially cocked.  This is helpful to allow cross-bolt safeties or to allow the retraction of the firing pin on firearms, such as double-barrel shotguns, that require the expended casing to move across the firing pin while being opened.

Recoil Shields--The recoil shields are located on each side of the standing breech on a revolver and serve to hold the cartridges in the proper place.  The rear of the recoil shields are usually smooth and round to prevent finger damage when the gun is pushed to the rear by the recoil.

Rifling--Rifling is found on the inside of the barrel tube of most rifles and pistols.  It is made up of a a spiral shaped series of grooves.  When a bullet begins its path down the barrel, it threads itself into the rifling, which causes the bullet to begin spinning.  The spinning bullet is more stable.

Rust Brown--I a finish on old guns that is produced by cleaning the metal, applying a controlled rusting solution, carding the surface rust from the metal, and repeating the process until the gun is a deep red/brown color.  The process is stopped with backing soda, wax, and oil.

Rust Blue--I a finish on old guns that is produced by cleaning the metal, applying a controlled rusting solution, boiling the rusted part in water, carding the surface rust from the metal, and repeating the process until the gun is a deep blue/black color.  The process is stopped by applying oil.

Saddle Ring--Is a ring attached to a firearm that is used with a lanyard to attach the gun to either a horse or its rider.  This prevents the loss of the gun if dropped while riding a horse.

Sear--The sear is found on the trigger and hammer.  It is made up of a carefully made notch in the hammer and a corresponding area of the trigger.  The two work together to hold the cocked hammer back and to provide a clean release when the trigger is pulled.

Short Starter--This is a short ramrod with a round ball on one end.  It is used to get the lead ball sized and started down the barrel.  The large round ball provides a more comfortable grip for applying pressure.

Single Action--Refers to guns, usually handguns, where the pulling of the trigger will only release the hammer and is not capable of also cocking the hammer.

Slip Hammering--Slip hammering is the art of rapidly shooting a single action revolver by using a two-hand grip, holding the trigger in the pulled position, and using the thumb of the second hand to pull the hammer back and release to fire the gun.  This is an alternative to fanning and can also accelerate damage to the gun action.

Solder--The act of combining two pieces of metal using heat and a lead or silver based metal that is melted in a manner that it adheres to both metals and binds them together.

Spitting--The gasses and lead that escapes through the cylinder/barrel gap on a revolver.

Standing Breech--Is found at the rear of the cylinder.  It serves as a backing plate for the chambers and the firing pins protrude through the standing breech to strike the primer in the shell.

Star--The machined spikes or recesses at the rear of a revolver cylinder that is pushed by the hand in order to move the cylinder.  Sometimes also called the Ratchet.

Tang--The tang is an area of metal that extends rearward from the receiver of a gun and into the stock.  It is usually inset into the wood and a tang screw is used to secure the stock to the tang.  Many lever action rifles have both an upper and lower tang that is used to sandwich the buttstock for strength.

Throat, Cylinder--The cylinder throat is the space just ahead of the cartridge casing that tapers down to hold the bullet.

Throat, Barrel--The portion of the barrel that is located in front of the chamber that transitions the diameter of the chamber to the diameter of the barrel with rifling.

Topstrap--The topstrap is found on most revolvers and provides strength to the frame by connecting the front and rear of the revolver along the top of the cylinder.  Topstraps were not used on early model colt revolvers and were believed to be introduces on the Remington-Beals 1857 revolvers.

Trigger--The trigger is a small lever that is usually operated with the shooter's index finger.  It's purpose is to release the hammer to fire the cartridge. 

Trigger Pull--The trigger pull is the amount of effort required to release the hammer.  It is usually measured in pounds.

Trigger Creep--Trigger creep is the amount of movement required of the trigger before the hammer is released. 

Trigger Guard--The trigger guard is the part of the frame that wraps around the trigger and prevents it from being damaged or accidentally activated.

Shot Cup-- Is a piece of thin and pliable plastic that is placed into the shotgun shell before putting in the shot.  It protects the shot from being deformed by the barrel and helps to hold the shot together into a tighter pattern.

Wad-- Is a plastic or fiber spacer that is placed between the powder and the payload.  Cap and Ball revolvers usually used a lubed fiber wad.  Shotgun shells for smokeless powder usually have a plastic wad that contains a shot cup.  Shotgun shells used with blackpowder usually use a fiber wad that is less affected by heat.  Shotgun shells used with blackpowder substitutes may be either fiber wad or conventional plastic.

Water Table--The water table is found on a double-barrel side by side shotgun.  It is the area of the receiver that is located between the Standing Breech and the hinge. 

Windage-- The horizontal measurement of sighting a firearm to the target.  Windage adjustments are made by moving the rear sight to the left or right.  They are occasionally made by moving or the front sight.

Wrist--Is the portion of a rifle or shotgun stock that is located behind the receiver where the shooting hand grips the stock. 

This site was last updated 01/29/03