ACTION - The heart of the gun, receiver, bolt or breech block feeding and firearm mechanism - see Box Lock, Rolling Block, or Side Lock.

ADJUSTABLE CHOKE - A device built into the muzzle of a shotgun to change from one choke to another.

AIR GUN - A gun which utilizes compressed air or gas to launch the projectile.

APERT'URE SIGHT - A rear sight consisting of a hole or aperture through which the front sight and target are aligned.

AUTO LOADING - See semi-automatic.

BACKSTRAP - That part of the revolver or pistol frame that is exposed at the rear of the grip.

BARREL BAND - A metal band, either fixed or adjustable, around the forend of a gun that holds the barrel to the stock.

BARREL THROAT - The breech end of a revolver barrel is chambered and somewhat funneled for passage of bullet from cartridge case mouth into barrel.

BEAVERTAIL FOREND - A wider than normal forend.

BLUING - The blue or black finish of the metal parts of a gun. The process is actually one of controlled rusting and brushing and is usually created with an acid bath. Bluing minimizes light reflection, gives a "finish" to the bare metal, and protects somewhat against rust.

BORE - Inside of a barrel. Also the diameter of the barrel as measured across the lands of a rifled barrel.

BOXLOCK ACTION - Typified by Parker shotgun in U.S. and Westley Richards in England. Generally considered not to be as strong as the side lock. Developed by Anson & Deeley, the box lock is hammerless. it has two disadvantages: Hammer pin must be placed directly below knee of action, which is its weakest spot, and action walls must be thinned out to receive locks. These are inserted from below into large slots in action body, which is then closed with a plate. Greener crossbolt, when made correctly, overcomes many of the box lock weaknesses.

BREECH - That portion of a gun which contains the action, the trigger or firing mechanism, the magazine, and the chamber portion of the barrel(s). An imprecise term generally including all the essential working parts of a gun.

BUCKHORN SIGHT - An open, metallic rear sight with sides that curl upward and inward.

BULL BARREL - A heavier, thicker than normal barrel with little or no taper.

BUTT PLATE - A protective plate attached to the butt.

CALIBER - The diameter of the bore.

CHAMBER - Rear part of the barrel that has been reamed out so that it will contain a cartridge. When the breech is closed, the cartridge is supported in the chamber, and the chamber must align the primer with the firing pin, the bullet with the bore.

CHAMBER THROAT - Also called THROAT, is that area in the barrel that is directly forward of the chamber and that tapers to bore diameter.

CHARCOAL COLOR CASEHARDENING - A method of hardening steel and iron while imparting to it colorful swirls as well as surface figure. Metal is heated by means of animal charcoal to 800-900° C, then plunged into cold water.

CHECKERING - A functional decoration applied to pistol grips and forends consisting of pointed pyramids cut into the wood.

CHOKE - The muzzle constriction on a shotgun to control spread of the shot.

COCKING INDICATOR - Any device which the act of cocking a gun moves into a position where it may be seen or felt in order to notify' the shooter that the gun is cocked. Typical examples are the pins found on some highgrade hammerless shotguns which protrude slightly when they are cocked, and also the exposed cocking knobs on bolt-action rifles. Exposed hammers found on some rifles and pistols are also considered cocking indicators.

COMB - The portion of the stock on which the shooter's cheek rests.

COMBINATION GUN - Generally a breakopen shotgun configuration fitted with at least one shotgun barrel and one rifle barrel. Such guns may be encountered with either two or three barrels, and less frequently with as many as four or five, and have been known to chamber for as many as four different calibers.

COMPENSATOR - A recoil-reducing device which mounts on the muzzle of a gun to deflect part of the powder gases up and rearward. Also called a "muzzle brake".

CRANE - In a modern solid-frame, swingout revolver, the U-shaped yoke on which the cylinder rotates, and which holds the cylinder in the frame.

CROWNING - The rounding or chamfering normally done to a barrel muzzle to insure that the mouth of the bore is square with the bore axis and that the edge is countersunk below the surface to protect it from impact damage. Traditionally. crowning was accomplished by spinning an abrasive coated brass ball against the muzzle while moving it in a figure eight pattern until the abrasive had cut away any irregularities and produced a uniform and square mouth.

CYLINDER - A rotating cartridge container in a revolver. The cartridges are held in chambers and the cylinder turns, either to the left or the right, depending on the gunmaker's design. as the hammer is cocked.

CYROGENIC TEMPERING - Computer controlled cooling process that relieves barrel stress by subjecting the barrel to a temperature of -310 degrees F for 22 hours.

DAMASCENE - The decorating of metal with another metal, either by inlaying or attaching in some fashion. Damascene is often confused with Damaskeening or engine turning.

DAMASCUS BARREL - A barrel made by twisting, forming and welding thin strips of steel around a mandrel.

DERRINGER - A small, usually large caliber pistol

DOUBLE ACTION - The principle in a revolver or auto-loading pistol wherein the hammer can be cocked and dropped by a single pull of the trigger. Most of these actions also provide capability for single action fire. In autoloading pistols, double action normally applies only to the first shot of any series, the hammer -being cocked by the slide for subsequent shots.

DOUBLE-BARRELED - A gun consisting of two barrels joined either side by side or one over the other.

DOUBLE-SET TRIGGER - A device which consists of two triggers one to cock the mechanism that spring-assists the other trigger, substantially lightening trigger pull.

DOVETAIL - A flaring machined or hand cut slot that is also slightly tapered toward one end. Cut into the upper surface of barrels and sometimes actions, the dovetail accepts a corresponding part on which a sight is mounted. Dovetail slot blanks are used to cover the dovetail when the original sight has been removed or lost; this gives the barrel a more pleasing appearance and configuration.

DRILLING - German for "triple", which is their designation for a three-barrel gun.

EJECTOR - Mechanical device used to eject empty cartridges from chamber(s).

ENGINE TURNING - Overlapped spots of circular polishing.

ENGLISH STOCK - A very straight, slender-gripped stock.

ENGRAVING - The art of carving metal in decorative patterns. Scroll engraving is the most common type of hand engraving encountered. Much of the factory engraving is roll on engraving; this is done mechanically. Hand engraving is a tedious and costly job.

ETCHING - A method of decorating metal gun parts.

EXTRACTOR - A device that withdraws the fired case from the chamber.

FALLING BLOCK - A single-shot action where the breech block drops straight down when the lever is actuated.

FIT AND FINISH - Terms used to describe over-all firearm workmanship.

FLOATING BARREL - A barrel bedded to avoid contact with any point on the stock.

FLOOR PLATE - The piece which closes the bottom of the magazine body.

FORCING CONE - Forward part of the chamber in a shotgun where the chamber diameter is reduced to bore diameter. The forcing cone aids the passage of shot into the barrel.

FOREND - The forward portion of a rifle or shotgun stock.

FREE RIFLE - A rifle designed for international-type target shooting. The only restriction on design is weight maximum 8 kilograms (17.6 lbs.).

FRONT STRAP - That part of the revolver or pistol grip frame that faces forward and often joins with the trigger guard. In target guns, notably the .45 ACP, the front strap is often stippled to give shooter's hand a slip proof surface.

GAUGE - The bore diameter of a shotgun.

GROOVES - The spiral cuts in the bore of a rifle or handgun barrel that give the bullet its spin or rotation as it moves down the barrel.

HAMMERLESS - Some "hammerless" firearms do in fact have hidden hammers, which are located in the action housing. Truly hammerless guns. such as the Savage M99, have a firing mechanism that is based on a spring-activated firing pin.

HEEL - Back end of the upper edge of the buttstock at the upper edge of the buttplate or recoil pad.

LAMINATED STOCK - A gunstock made of many layers of wood glued together under pressure. They are very resistant to warpage.

LANDS - Portions of the bore left between the grooves of the rifling in the bore of a firearm- In rifling, the grooves are usually twice the width of the land. Land diameter is measured across the bore, from land to land.

MAGAZINE - The container which holds cartridges under spring pressure to be fed into the gun's chamber.

MAGNUM - A modern cartridge with a higher-velocity load or heavier projectile than standard.

MAINSPRING - The spring that delivers energy to the hammer or striker. The recoil or operating spring in semiautomatic guns is a part of the breech closing system; is not the same as the mainspring.

MANNLICHER STOCK - full-length slender forend extending to the muzzle.

MICROMETER SIGHT - A finely adjustable target sight.

MONTE CARLO STOCK - A stock with an elevated comb used primarily for scoped rifles.

MUZZLE - The forward end of the barrel where the projectile exits.

MUZZLE BRAKE - A recoil-reducing device attached to the muzzle.

OVER UNDER - A two-barrel gun in which the barrels are stacked one on top of the other.

PARALLAX - Occurs in telescopic sights when the primary image of the objective lens does not coincide with the reticle. In practice. parallax is detected in the scope when, as the viewing eye is moved laterally. the image and the reticle appear to move in relation to each other.

PARKERIZING - A matted rust-resistant oxide finish, usually gray or gray-green in color, found on military guns.

PEEP SIGHT - A rear sight consisting of a hole or aperture through which the front sight and target are aligned.

PEPPERROX - An early form of revolving repeating pistol in which a number of barrels were bored in a circle in a single piece of metal resembling the cylinder of a modern revolver. Functioning was the same as a revolver, the entire cylinder being revolved to bring successive barrels under the hammer for firing. Though occurring as far back as the 16th century, the pepperbox did not become practical until the advent of the percussion cap in the early 1800's. Pepperboxes were made in a wide variety of sizes and styles, and reached their popularity peak during the percussion period. Few were made after the advent of practical metallic cartridges. Both single- and doubleaction pepperboxes were made. Single barreled revolvers after the 1 840s were more accurate and easier to handle and soon displaced the rather clumsy and muzzle heavy pepperbox.

POPE RIB - A rib integral with the barrel. Designed by Harry M. Pope, famed barrel maker and shooter, the rib made it possible to mount a target scope low over the barrel.

PROOFMARK - On European guns, is quite specific, indicating proof house and all proofs performed, sometimes also date of proof. Proof marks are applied to all parts actually tested, usually on the barrel, and that in the white that is, not blued, and without sights. In the U.S., there is no federalized or government proof house, only the manufacturer's in-house proofmark indicating that a firearm has passed their internal quality control standards per government specifications.

RECEIVER - That part of a rifle or shotgun (excluding hinged frame guns) that houses the bolt, firing pin, mainspring, trigger group, and magazine or ammunition feed system. The barrel is threaded into the somewhat enlarged forward part of the receiver, called the receiver ring. At the rear of the receiver, the butt or stock is fastened. In semiautomatic pistols, the frame or housing is sometimes referred to as the receiver.

RELEASE TRIGGER - A trap shooting trigger that fires the gun when the trigger is released.

RIB - A raised sighting plane affixed to the top of a barrel.

RIFLING - The spirally cut grooves in the bore of a rifle or handgun. The rifling stabilizes the bullet in flight. Rifling may rotate to the left or the right, the higher parts of the bore being called lands, the cuts or lower parts being called the grooves. Many types exist, such as oval, polygonal, button, Newton, Newton-Pope, parabolic, Haddan, Enfield, segmental rifling, etc. Most U.S.-made barrels have a right-hand twist, while British gunmakers prefer a left-hand twist. In practice, there seems to be little difference in accuracy or barrel longevity.

ROLLING BLOCK ACTION - Single shot action, designed in the U.S. and widely used in early Remington arms. Also known as the REMINGTON-RIDER action, the breechblock. actuated by a lever, rotates down and back from the chamber. Firing pin is contained in block and is activated by hammer fall.

SCHNABEL FOREND - Erroneously also called shnobel or schnobel. A curved and sometimes carved shape at the forend that resembles the beak of a bird (Schnobel in German). This type of forend is common on Austrian and German guns; was popular in the U.S., but the popularity of the schnable forend comes and goes with the seasons. A schnabel forend is often seen on custom stocks and rifles.

SHORT ACTION - A rifle designed for shorter cartridges.

SIDELOCK - A type of action, usually shotgun, where the moving parts are located on the lock plates inletted in the stock. Usually found only on high quality shotguns and rifles.

SIDE PLATES - Ornamental additions to simulate a side lock gun on a boxlock.

SINGLE ACTION - A revolver design which requires the hammer to be manually cocked for each shot. Also an auto-loading pistol design which requires manual cocking of the hammer for the first shot only.

SINGLE TRIGGER - One trigger on a double-barrel gun. It fires both barrels singly by successive pulls.

SLING SWIVELS - Metal loops affixed to the gun on which a carrying strap is attached.

SPUR TRIGGER - A trigger mounting system that housed the trigger in an extension of the frame in some old guns. The trigger projected only slightly from the front of the extension or spur, and no trigger guard was used on these guns.

SUICIDE SPECIAL - A mass-produced variety of inexpensive rimfire single action revolvers, usually with a spur trigger. So named because many suicides were committed with this type of inexpensive handgun. These guns carried many fancy names; those in good condition have become true collector's items.

TAKE DOWN - A gun which can be easily taken apart for carrying or shipping.

TANG - An extension of the receiver into the stock.

TOP STRAP - The upper part of a revolver frame, which often is either slightly grooved - the groove serving as rear sight - or which carries at its rearward end a sight that may be adjustable.

TRAP STOCK - A shotgun stock with greater length and less drop for trap shooting.

TWIST BARRELS - A process in which a steel rod (called a mandrel) was wrapped with "skelps" - ribbons of iron. The skelps were then welded in a charcoal fire to form one piece of metal, after which the rod was driven out to be used again. The interior of the resulting tube then had to be laboriously bored out by hand to remove the roughness. Once polished, the outside was smoothed on big grinding wheels, usually turned by water power.

VENTILATED RIB - A sighting plane affixed along the length of a shotgun barrel with gaps or slots milled for cooling purposes.

YOUTH DIMENSIONS - Usually refers to shorter stock dimensions and/or lighter weight enabling youth/women to shoot and carry a lighter, shorter firearm.