ACPAn abbreviation meaning: Automatic Colt Pistol. It is commonly used to designate specific calibers, particularly those which were originally designed by John Moses Browning for the Colt Firearms Company. Automatic Colt Pistol, a type of ammunition. For example: as in .45 ACP, .380 ACP, and .25 ACP
ACTIONThe working mechanism of a firearm involved with presenting the cartridge for firing, and in removing the spent casing and introducing a fresh cartridge. See also: single action, double action.
ACCIDENTAL DISCHARGEAn unexpected and undesirable discharge of a firearm caused by circumstances beyond the control of the participant(s) such as a mechanical failure or parts breakage. There are very, very few firearms related “accidents” and if the “4 Rules” are followed there will hopefully be no injury. Compare with Negligent Discharge.
ADJUSTABLE STOCKhe stock is the wooden, polymer, or metal handle of a long gun that extends from the trigger back to where the gun is braced against the shoulder. An adjustable stock is one that can be easily lengthened or shortened to fit shooters of different sizes.
ADJUSTABLE TRIGGERA trigger that can be easily adjusted by the user. Adjustable triggers are common on specialized target-shooting firearms, but rare on self defense firearms.
AIRGUNNot a firearm but a gun that uses compressed air or CO2 to propel a projectile. Examples: BB gun, pellet gun, CO2 gun.
AMBIDEXTEROUS SAFETYA manual, external safety which can be easily reached with either hand. Usually one lever on each side of the firearm.
AMMOShort for Ammunition
AMMUNITIONThe “packaged” components that are needed in order to fire in a case or shell holding a primer, (which produces the spark) a charge of propellant (gunpowder) and a projectile (bullets, slug or pellets.) Sometimes called “fixed ammunition” to differentiate from the individual components placed separately in muzzleloaders. A single unit of ammunition in modern firearms is called a cartridge. The units of measure for quantity of ammunition is rounds. There are hundreds of sizes of ammunition, examples include .223 Remington, 9mm Luger, 30.06, .308 Winchester, .300 Winchester Magnum, and .50 Browning Machine Gun (BMG). The ammunition used must match the firearm.
ANTIQUEBy federal definition, a firearm manufactured prior to 1899 or a firearm for which ammunition is not generally available or a firearm incapable of firing fixed ammunition.
APERTURE SIGHTAn iron sight system of aligned markers used to assist in the aiming of a device such as a firearm, crossbow, or telescope that excludes the use of optics as in a scope. Also known as Peep Sights.
AR-15is a widely owned semi-automatic rifle. The AR does not stand for “Assualt Rifle” as many believe, it was named after the manufacturer that first built it, Armalite.
ARMOR-PIERCING AMMUNITIONA type of ammunition designed to penetrate armor or armor-plated targets such as tanks, trucks, and other vehicles. An armor-piercing shell must withstand the shock of punching through armor plating. Shells designed for this purpose have a greatly strengthened case with a specially hardened and shaped nose, and a much smaller bursting charge.
ARSENALA government establishment where firearms and ammunition are stored, repaired, or manufactured. The term is misused by the media to mean more than one firearm or any quantity of ammunition, as in “they found an arsenal.
ARTILLERYLarge bore diameter (nominally 3″ or greater) firearms designed to be operated by a crew of individuals. They are utilized to project explosive, armor defeating, incendiary, or nuclear projectiles over great distances. They are normally moved by vehicle because of their size and weight. “Cannon,” mortars, howitzers, and similar are considered artillery.
ASSAULT RIFLEA military firearm which fires a reduced-power rifle round, and can shoot in both fully-automatic and semi-automatic modes.
ASSAULT WEAPONA political term with no fixed definition, being defined differently by different jurisdictions. Because the actual definition is so fluid, laws written to regulate assault weapons often define the term by various cosmetic characteristics which do not affect a firearm’s power or function in any fundamental way. Despite public perception, assault weapons are not machine guns. They are semi-automatic firearms, not fully automatic firearms.
The term is distinct from the term assault rifle, which is a technical term with a specific meaning widely accepted both in law and within the military and firearms communities.
AUTOLOADERA firearm that automatically loads the next cartridge to be fired into the chamber either upon the pull of the trigger in an open bolt design or upon the firing of the previous round in a close bolt design. Over time this term has been shortened to just “auto” and sometimes “automatic” thus creating confusion between a full-auto firearm and a semi-automatic firearm.
AUTOMATICA firearm designed to feed cartridges, fire them, eject their empty cases and repeat this cycle as long as the trigger is depressed and cartridges remain in the feed system. Examples: machine guns, submachine guns, selective-fire rifles, including true assault rifles. A fully automatic firearm is capable of sequentially firing two or more cartridges with a single pull of the trigger. A fully automatic firearm is also called a machine gun.
Automatic can also refer to a semi-automatic firearm.
BALLOriginally a spherical projectile, now generally a fully jacketed bullet of cylindrical profile capped with a round nose.
BALLISTICSThe science of cartridge discharge and the bullet’s flight. Internal ballistics deals with what happens inside of a firearm upon discharge. External ballistics is the study of a projectile’s flight, and terminal ballistics is the study of the impact of a projectile.
BALLISTIC FINGERPRINTA fired case has marks upon it that it picked up from the extractor, ejector, and breechface of the gun when the shot went off. A bullet fired through a rifled barrel also has rifling marks unique to the barrel that launched it. A record of these marks, when stored in a central database, is called a ballistic fingerprint. Some states require this record to be made by law, so that individual guns can be located from bullets or casings found at the scene of a crime.
BARRELThe metal tube through which the bullet or shot travels. The barrel serves the purpose of providing direction and velocity to the bullet.
BATTERYMost firearms do not have literal batteries. But a firearm is said to be in battery when the breech is fully closed and locked, ready to fire. When the breech is open or unlocked, the gun is out of battery and no attempt should be made to fire it. A semi-automatic is out of battery when the slide fails to come all the way forward again after the gun has fired, making it dangerous or impossible to fire the next round. This condition can be created by a misfeed, a dirty gun, weak springs, the shooter’s thumbs brushing against the slide, riding the slide, or any of several other causes.
BACKSTOPAnything that will safely stop a bullet and prevent it from hitting anything else after the target is struck.
BACKSTRAPA handgun term. The rearmost surface of the grip. The rear of two gripstraps on a handgun, which lies beneath the heel of the hand when gripping the gun.
BAYONET LUGA mounting point on a small arm that allows a bayonet or other accessory to be attached.
BEAVERTAILA large piece of curved metal at the top of the grip which protects the user’s hand from getting bitten by the hammer. It is nearly always the top part of the grip safety commonly found on many 1911-style pistols.
BENCHREST (Shooting)A shooting sport in which the competitors seek to place five or ten consecutive shots into the smallest possible group on a paper target at various ranges. All firing is done from an artificially supported shooting position. It is a severe test of the mechanical precision of both the small arm and its ammunition.
BERMOn an outdoor shooting range, a large pile of dirt that functions as a backstop.
BIATHLONA shooting sport that combines both skiing and rifle shooting. It is the only shooting activity in the Winter Olympics. There is also a summer biathlon which involves running and shooting but it is not yet an Olympic event.
BIPODA two legged support for the front end of a rifle to stabilize the gun while shooting.
BIRDSHOT A type of shotgun ammunition which uses very small pellets with individual projectiles of less than .24″ in diameter designed to be discharged in quantity from the shotgun. The size of the shot is given as a number or letter–with the larger number the smaller the shot size. It is so named because it is most often used for hunting birds. The finest size generally used is #9 which is approximately .08″ in diameter and the largest common size is #2 which is approximately .15
BLACKPOWDERThe earliest type of firearms propellant that has generally been replaced by smokeless powder except for use in muzzleloaders and older breechloading guns that demand its lower pressure levels.
ACTIONThe working mechanism of a firearm involved with presenting the cartridge for firing, and in removing the spent casing and introducing a fresh cartridge. See also: single action, double action.
BLOWBACK A semi-automatic firearm whose breechblock and barrel are not mechanically locked together when fired. In such case the breechblock immediately begins to separate from the barrel upon firing. Blowback is used in comparatively low powered weapons, in which inertia of the breechblock, and cartridge wall adhesion against the chamber, are sufficient enough to retard opening until breech gas pressures have fallen to a safe level.
BLANK CARTRIDGE round loaded with blackpowder or a special smokeless powder but lacking a projectile. Used mainly in starting races, theatrical productions, troop exercises and in training dogs.
BLUINGThe chemical process of artificial oxidation (rusting) applied to gun parts so that the metal attains a dark blue or nearly black appearance.
BOAT TAILA type of projectile that has a tapered base (rear end) that reduces the drag from the air as it travels to its target.
BOLTThe working mechanism of a firearm involved with presenting the cartridge for firing, and in removing the spent casing and introducing a fresh cartridge. See also: single action, double action.
BOLT ACTIONA type of firearm, almost always a rifle, in which an empty shell casing is removed from the firing chamber by the turning and retraction of a metal cylinder shaped mechanism called a bolt. A new, unfired, cartridge is inserted and secured into the chamber by reversing the action of the bolt.
BOREThe hollow portion of a barrel through which the bullet travels during it’s acceleration phase.
A smooth-bore firearm is one that does not have rifling on the barrel’s internal surface.
A big-bore firearm is one that fires a large caliber.
A small-bore firearm is one that fires a small caliber.
BORE DIAMETERThe diameter of the inside of the barrel after boring, but before rifling.
BORE AXIS An imaginary line which runs right down the center of the handgun’s barrel and out though the back end of the gun. A handgun may have a high bore axis, with the imaginary line running out into space well above the shooter’s hand. Or it may have a low bore axis, with the imaginary line running either straight through the shooter’s hand or just skimming the surface slightly above her hand. A high bore axis tends to create greater perceived recoil and more muzzle flip when firing the gun than does a low bore axis.
BOTTLENECKEDA type of cartridge whose bullet diameter is substantially less than the body diameter of the casing.
BRASS A slang term for an empty shell casing. Most shell casings are made of the metal alloy known as brass.
BREAK (Trigger Break)The point at which the trigger allows the hammer to fall, or releases the striker, so that the shot fires. The ideal trigger break is sudden and definite. “Like a glass rod” is the cliché term shooters use to describe the ideal crisp, clean break.
BREECHThat portion of the gun that contains the rear chamber portion of the barrel. The rearmost end of a barrel, closest to the shooter.
BEECH LOADING GUNa firearm in which the cartridge or shell isinserted or loaded into a chamber to the rear portion of a barrel.
BREECH BLOCKThe part of the weapon that seals the rear of the chamber (the breech) while the gun is firing, preventing the rearward escape of gases.
BREECH FACEThat portion of the breech block which touches the cartridge when the breech is closed.
BREECH OPENINGThe open rear of the barrel through which cartridges are inserted into the chamber.
BRICKA box of ammunition roughly equal in size and weight to a brick. Most often used to describe a 500-round container of 22 Long Rifle ammunition.
BUCKSHOTA type of shotgun ammunition that uses medium-sized to large-sized pellets of .24″ in diameter or greater, designed to be discharged in quantity from a shotgun. Generally the larger the pellets, the fewer of them there are in casing.
BULLETThe single metal projectile expelled from a gun. It is not the same as a cartridge, the cartridge is complete package, which includes the case, primer, powder, and bullet, which is called or a round. Bullets can be of many materials, shapes, weights and constructions such as solid lead, lead with a jacket of harder metal, round-nosed, flat-nosed, hollow-pointed, etc.
BULLET PROOF VESTA popular but incorrect term for bullet resistant clothing.
BULLET TRAPA type of backstop that catches the fired bullet and prevents it from exiting the area. Bullet traps are most commonly used on indoor ranges.
BULLPUPA rifle configuration in which the action and magazine are located behind the trigger. This makes the overall length of the firearm shorter than it otherwise would be.
BUTTThe base of the grip on a handgun and the rearmost portion of the stock on a long gun that braces against the shoulder.
BULL BARREL“Bull barrels” are barrels that are not tapered at all. These very heavy barrels, designed for extreme accuracy, are usually seen on target rifles.
CABLE LOCKA cable with a padlock at the end. It is threaded through the action of the firearm.
CALIBERThe diameter of the bore of a firearm measured as a fraction of an inch. Although such a measurement may be frequently stated in millimeters. It is correctly expressed as “.40 caliber” (note the decimal point) or as “10 millimeter” (without “caliber” or the leading decimal point). Caliber numbers when used to identify the size of the bullet a gun will file are usually followed by words or letters to create the complete name of the cartridge. These letters often represent a brand name or an abbreviation for the name of the company that first introduced the round.
CANSlang term for a firearm sound suppressor.
CANNELURE A groove or indention around the circumference of a bullet. Its purpose is to permit the cartridge casing to be crimped tightly against the bullet shank to hold it firmly to the casing. A groove or indention around the circumference of a bullet. Its purpose is to permit the cartridge casing to be crimped tightly against the bullet shank to hold it firmly to the casing.
CANTTilting the firearm slightly to one side, so the grip is no longer vertical in relation to the ground. Canting the firearm can make precision shooting more difficult, but may be necessary in some circumstances.
CARBINEA rifle with a relatively short barrel. Any rifle or carbine with a barrel less than 16″ long must be registered with the Bureau of Alcohol, Tobacco and Firearms. Shotguns with barrels less than 18″ long fall into the same category. Commonly used today to indicate any rifle of short overall length.
CARTRIDGEA single, complete round of ammunition which includes the case, primer, powder, and bullet
CASE, CASINGThe envelope (container) of a cartridge. For rifles and handguns it is usually of brass or other metal; for shotguns it is usually of paper or plastic with a metal head and is more often called a “shell.”
CENTER-FIREA cartridge with its primer located in the center of the base of the case.
CENTER OF MASS (COM)For self-defensive shooters, COM represents the area of an attackers torso within which the most vital organs are likely to be disrupted by a gunshot. Shooting to COM is considered the most expedient way to stop an assailant from continuing threatening behavior.
CHAMBER The rear part of the barrel that is formed to accept the cartridge to be fired. A revolver employs a multi-chambered rotating cylinder separated from the stationary barrel.
CHAMBER THROATThis is the area in the barrel that is directly forward of the chamber, which tapers to the bore diameter.
CHARGERA device typically made from stamped metal which holds a group of cartridges for easy and virtually simultaneous loading into the fixed magazine of a firearm.
CHOKEA constriction at or near the muzzle of a shotgun barrel that affects shot dispersion.
CLAY PIGEONOriginally, live pigeons were used as targets, but they were gradually replaced with clay disks and ultimately banned. Later clay has been replaced with more suitable raw materials.
CLEARINGUnloading a gun and double checking that it is unloaded or fixing a malfunction so that the gun is ready to fire again.
CLICKSA unit of adjustment for a sight.
CLIPThe controversial name commonly used to describe a magazine which is an ammunition storage and feeding device Magazines may be integral to the firearm (fixed) or removable (detachable). The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action of the firearm.
CLOSED BOLT FIRING (SYSTEM)A type of firearm in which the action is closed, with a cartridge in the chamber prior to firing. When the trigger is pressed the cartridge is fired, and the action cycles loading another cartridge into chamber and when firing is stopped the bolt remains closed and the chamber remains loaded.
COCKThe term referring to the action of manually drawing the hammer back against its spring until it becomes latched against the sear, or sometimes the trigger itself, arming the hammer to be released by a subsequent pull of the trigger. Some external hammers, and all internal hammers, may be cocked simply by pulling the trigger
COCKEDA state of readiness of a firearm. The hammer (or similar mechanism if there is no hammer) only needs to be released by the trigger to cause the gun to fire.
COLD CLEAN BOREThe first shot from a rifle that has been cleaned, and not fired recently may go to a different point of impact, for the same point of aim than a rifle that has been fired recently. This first shot is referred to as a shot from a cold, clean, bore. See also fouling shot.
COLD RANGEPistol must be unloaded until it is your turn to shoot
COLLAPSIBLE STOCKA stock on a long gun that can be shoved into itself to shorten it, either for storage or to make the gun fit shooters of different sizes.
COMPENSATORAlso call a Muzzle Brake. A device attached to or made as part of a firearms barrel designed to reduce recoil or muzzle movement on firing. They generally increase muzzle blast. The may also, but not necessarily so, diminish muzzle flash.
CONCEALEDHidden from view. A handgun is concealed when it is carried in such a manner that is unseen
CONTROLLED PAIRTwo shots fired in rapid succession. It is different from a double tap because in a controlled pair, the second shot will be fired after the shooter has obtained a second sight picture, whereas in a double tap both shots are fired based upon the initial sight picture alone.
COVERAnything an intended victim hides behind that will probably stop a bullet.
COVER GARMENTAny piece of clothing that covers the holstered gun. When the gun is worn on the belt, the most common types of cover garments are vests, sweaters, and jackets.
CO-WITNESS SIGHTINGis the use of any iron sight mounted onto a rifle that is fitted with an optical sight as a primary sighting system. They come in two basic configurations, fixed or flip-up. The idea is that if you align your red dot and your iron sights you have a backup aiming system on the gun.
CROSS-DOMINANTThis means a shooter who is right-handed but left-eyed, or left-handed and right-eyed.
CROSSHAIRSThe cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.
CROWNThe area inside the bore nearest the muzzle. Damage to the crown can severely and adversely affect the firearm’s accuracy.
CYLINDERA rotating cartridge holder in a revolver. The cartridges are held in the chambers and the cylinder turns, either to the left or to the right depending on the gun maker’s design, as the hammer is cocked.
CYLINDER DRUMOn a revolver, a spring activated device housed in the bottom of the frame beneath the cylinder that engages alignment notches in the cylinder. It stops the cylinder’s rotation and holds it in place each time a chamber in the cylinder is in alignment with the barrel.
DECOCKEROn double-action semi-automatic firearms, a lever that mechanically lowers the hammer without firing the gun.
DELAYED BLOWBACKA self-loading firearm whose breechblock and barrel are not positively locked together, but which incorporates a mechanism which initially restricts the breechblock from moving when fired, delaying its opening.
DERINGERA small single-shot or multi-barreled (rarely more than two) pocket pistol. The design was first produced by Henry Deringer, under the brand name Deringer. When used to refer to any other brand of the same design, derringer is spelled with two r’s and is not capitalized.
DETONATETo explode with great violence. It is generally associated with high explosives e.g. TNT, dynamite, etc., and not with the relatively slow-burning smokeless gunpowders that are classed as propellants.
DOUBLE ACTION (DA)A type of firearm that may be discharged either by manually cocking the weapon and then pulling the trigger or by using trigger action to both cock and fire the weapon. Originally used only for revolvers but now common in semi-autos as well, Now it commonly means a revolver or pistol on which a long trigger pull can both cock and release the hammer to fire the weapon. In a revolver this action also rotates the cylinder to the next chambered round.
DOUBLE ACTION / SINGLE ACTION (DA/SA)A type of firearm that is designed to operate in double action on the first shot, and in single action on the second and subsequent shots.
DOUBLE-ACTION ONLY (DAO)s a type of firearm in which the firing mechanism cannot be cocked in a single-action stage. Firing always occurs as a double-action sequence where pulling the trigger both cocks and then fires the gun.
DOUBLE BARRELA shotgun with two barrels either side by side or one over the other.
DOUBLE FEEDA malfunction in which the spent case fails to eject from a semi-automatic firearm and blocks the chamber. As the fresh round is brought forward it cannot enter the chamber. It is cleared by stripping the magazine from the gun, racking the slide several times to eject the spent case, and then reloading.
DOUBLE TAPTwo shots fired in rapid succession. Generally without getting a new sight picture on the target. If the second shot is fired after a second sight picture is captured it may instead be called a controlled pair.
DOWN RANGEThe area of a gun range where firearms are pointed when they are fired. The area of the range forward of the firing line.
DRAMS A black powder weight measure or smokeless powder in the case of shotgun ammunition.
DROP SAFETYA mechanical safety that prevents the gun from firing when it is unintentionally dropped. Some state governments require drop-testing of all handgun designs sold within the state.
DRY FIRINGThe operation of a firearm without the use of ammunition, as a means of gaining familiarity and technique. Dry firing must be done very carefully with a verified unloaded gun.
DUDA round of ammunition that does not fire.
DUMMY ROUNDAn inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions and also used in dry fire practice.
EAR PLUGShearing protection that fits inside the ear canal.
EARMUFFShearing protection that completely covers both ears and is usually attached to a headband
EARSSlang for hearing protection, muffs or plugs. The use of specially designed ear muffs or plugs that reduce the intensity of the sound reaching the ears is of course recommended. Some of the guns are so loud that a single shot can can cause permanent damage to unprotected ears.
EJECTORA spring-activated mechanism for the ejection of ammunition or and empty shell casing. On doubles, each barrel has a separate ejector.
EJECTOR STAROn a revolver, the collective ejector, manually operated through the center of an opened cylinder, when activated, clears all chambers at once.
EJECTION PORTThe opening through which the empty, spent ammunition case is ejected from of a firearm.
EJECTION RODThe sliding metal dowel located at the muzzle end of a revolver cylinder. After firing, the shooter opens the cylinder and depresses the front end of the ejection rod, which forces the empty cases out of the cylinder.
ELECTRONIC HEARING PROTECTIONEar muff hearing protection that has internal electronics that amplify human voices while excluding all noises louder than a given decibel rating.
ELEVATIONThe setting on the sights of a firearm that controls the vertical placement and the altitude above mean sea level. This is important for long range precision shooting because the air density changes with elevation and affects the path of the bullet.
EXPLOSIVEAny substance (TNT, etc.) that, through chemical reaction, detonates or violently changes to gas with accompanying heat and pressure.
EXTRACTORA device that withdraws or elevates a fired shell casing from the chamber as the breech mechanism (slide) is opened.
EXTERNAL SAFETYA safety lever found on the outer surfaces of the firearm and accessible to the user.
EYESSlang for safety glasses or other protection for the eyes. All shooters and spotters are required to wear eye protection while shooting is in progress.
FACTORY AMMOAmmunition that has been assembled by a commercial vendor of ammunition and sold in retail stores. This is as opposed to Hand loads which have been assembled by individuals and are not typically sold.
FAILURE TO EXTRACTA semi-automatic firearm malfunction in which the extractor fails to move the empty case out of the way as the slide travels back. A failure to extract often causes double-feed malfunction.
FAILURE TO FEEDA semi-automatic firearm malfunction in which the slide passes entirely over the fresh round, failing to pick it up to insert into the chamber as the slide returns to battery.
FAILURE TO FIREAny malfunction that results in no shot fired when the trigger is pulled. Commonly caused by a failure to feed, bad ammunition or a broken firing pin.
FIREPOWERA volume of fire delivered by a military unit. Incorrectly used by the media to mean the ability of a small arm to be discharged many times without reloading.
FIREARMA rifle, shotgun or handgun using gunpowder as a propellant. By federal definition, under the 1968 Gun Control Act. Air guns are not, by definition, firearms.
FIRING LINEA line, either imaginary or marked, from which people shoot their firearms down range.
FIRING PINA needle like metal part of a modern firearm that gives a vigorous strike to the primer initiating the firing of the cartridge.
FIRING PIN BLOCKA type of internal safety that prevents the firing pin from moving forward for any reason unless the trigger is pulled.
FIXED AMMUNITIONA complete cartridge of several obsolete types and of today’s rimfire and center-fire versions.
FLASH HIDER/FLASH SUPPRESSORA muzzle attachment intended to reduce visible muzzle flash caused by the burning propellant. Flash reducers lessen glare as seen by the shooter, but do not hide the flash from other observers to the front or side of the firearm.
FLAT POINT OR FLAT NOSE A bullet shape with a flat nose rather than a rounded one.
FLINCHJerking the gun downwards just before the shot fires. Commonly caused by learning to shoot with a gun more powerful then they are ready for.
FOLDING STOCKA long gun stock that may be doubled over for conveniently compact storage.
FOLLOW THROUGHHolding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.
FOULINGThe gritty residue that cleaned out of the barrel and all areas of the firearm in order to clean it.
FOULING SHOTA shot fired in a clean rifle barrel to put the barrel into the normal slightly dirty state from which it is fired. Often, a rifle will shoot to a different point of aim with this shot as compared to the subsequent shots.
FOUR RULESThe four universal rules of firearms safety, which apply every single time a firearm is handled in any way or for any reason.
Rule One: All guns are always loaded. (Treat them so!)
Rule Two: Never point your firearm at anything you are not willing to destroy.
Rule Three: Never put your finger on the trigger unless your sights are on target (and you have made the decision to fire).
Rule Four: Be sure of your target and what is behind it.
FORENDThat part of the stock forward of the action and located below the barrel or barrels. It is designed to give the shooter a place to hold the front end of the gun and protects the shooter’s hand from getting burned on the hot barrel.
FRAMEThe common part of a handgun to which the action, barrel and grip are connected.
FRONT SIGHTThe front sight is placed at the muzzle end of the barrel. It is often (but not always) in the form of a dot or a blade. To attain a proper sight picture and shoot with the greatest degree of accuracy, the shooter’s eye should be focused sharply upon the front sight while shooting, allowing both the rear sight and the target to blur somewhat.
FRONT STRAPThe part of a revolver or pistol grip frame that faces forward and often joins with the trigger guard.
FULL METAL JACKET FMJA type of round in which in which the lead core bullet is encased in a harder metal jacket on the front and sides.
GAPGlock Auto Pistol, a type of ammunition.
GASThe superheated air and other stuff produced by burning powder. Gas pressure is what sends the bullet downrange.
GAS OPERATEDThe superheated air created by burning powder. A gas-operated firearm is one that uses the energy from these superheated gases to work the action.
GAUGEThe bore size of a shotgun determined by the number of round lead balls of bore diameter that equals a pound. It is used like “Caliber” for the shotgun.
GHOST-RING SIGHTA type of aperture rear sight with a large opening and a thin rim that seems to fade out when the shooter looks through it. Sometimes installed on rifles and shotguns intended for home defense or police use.
GRAINSA unit of weight measurement used for bullets and gunpowder. The more grains, the heavier the bullet. Powder is also measured by grains, but this is generally of interest only to re-loaders. There are 7000 grains to a pound.
GREEN AMMUNITIONAmmunition that contains no lead in any component.
GRIPSThe handle used to hold a handgun. Often refers to the side-panels of the handle or the method by which the shooter holds the handgun.
GRIP PANELSThe interchangeable surfaces that are installed on the part of the gun that you hold. Users change grip panels to improve the look or feel of the firearm, or to personalize it so that the gun is more suited to a different hand size. Some grip panels are chosen for function, while others are chosen for looks. Common grip-panel materials are wood, plastic, and rubber.
GRIP SAFETYA passive, external safety typically located on the backstrap, which must be fully depressed to release the trigger. Most 1911-pattern pistols feature a grip safety.
GRIPSTRAPSThe exposed portion of a handgun’s frame, the front strap and backstrap, that provides the foundation for the handgun’s grip.
GROOVESSpiral cuts into the bore of a barrel that give the bullet its spin or rotation as it moves down the barrel. Technically is is the portion of the bore in a rifled barrel that has been machined away.
GROUPA gathering of holes in the target. The group size is measured by finding the bullet holes that are the furthest apart from each other and measuring from the center of one hole to the center of the other hole.The closer the holes, the better. Obviously the number of shots fired affect the group size. Typical numbers are three, five and ten. From a statistics viewpoint a three shot group is virtually meaningless as a measurement of firearm accuracy. Five shot groups are acceptable. Some advocate a seven shot group as a good tradeoff between economy and statistical relevance.
GUNPOWDERChemical substances of various compositions, particle sizes, shapes and colors that, on ignition, serve as a propellant. Ignited smokeless powder emits minimal quantities of smoke from a gun’s muzzle; the older black-powder emits relatively large quantities of whitish smoke.
HAIR TRIGGERA trigger that breaks from an extremely light touch.
HAMMEROn guns so equipped, the hammer is the part that rotates to provide the percussive impact on the primer. The firing pin may be struck by the hammer, or the firing pin may be a part of the hammer. Not all guns have hammers. Many guns are equipped with strikers: notably Glock pistols and the vast majority of bolt action rifles. Hammers may be exposed or shrouded, spurred or bobbed.
HAMMER SPURThe thumb-piece on the top rear of the hammer that enables it to be manually drawn back to full cock.
HAMMERLESSA revolver or pistol design that actually have hammers but are fully encased inside the frames, hammer designs where the spurs have been removed for concealment, or striker-fired pistols that are truly hammerless.
HANDGUNSynonym for pistol. designed to be fired while held in one or both hands, rather than while braced against the shoulder.
HANDLOADSCartridges assembled by an individual person from the individual components (primer, shell casing, gunpowder, and bullet) and are typically tailored specifically for their firearm
HARDBALLSlang for a full metal jacket bullet with a round nose. The term is most commonly used in referring to .45 ACP caliber ammunition, but may be used for other calibers as well.
HEEL (OF A STOCK)The top of the butt, when the gun is in position on the shoulder to be fired, is called the heel.
HEAVY TRIGGERA trigger that requires a lot of pressure to pull it past the break point. Rifles tend to have considerably lighter triggers than handguns, and even a heavy rifle trigger is often lighter than a light handgun trigger.
HIGH-CAPACITY MAGAZINE An inexact, non-technical term indicating a magazine holding more rounds than might be considered “average.”
HIGH KNEELINGA shooting position in which one or both knees are touching the ground, but the shooter is otherwise erect.
HMRHornady Magnum Rimfire, a type of ammunition.
HOLLOW-POINT BULLETA bullet with a concavity in its nose to increase expansion on penetration of a solid target. some hollow-point’s are also designed to fragment as they expand. They are least likely to over-penetrate the target and harm an innocent bystander. Commonly used for self-defense
HOLSTERA gun holder that may be strapped to a human body, or affixed to the inside of a pack or bag, or dropped into a pocket. A holster serves to protect the gun’s mechanisms and finish, to provide security by covering the trigger so it cannot be pulled inadvertently, and to present the grip of the gun at a constant angle for easy access. Some holsters also serve to obscure the outline of the gun so it may be more easily concealed. Typically made from leather or in plastic.
HOT RANGEPistol can be carried loaded, also a range where the range master has given the order to commence fire.
INTEGRAL LOCKA built in lock that may prevent the firearm from being fired.
INTERNAL SAFETYA safety which is placed within the gun and is not accessible to the user. Internal safeties are generally designed to prevent unintentional discharges when the gun is dropped or mishandled.
IRON SIGHTSThe mechanical sighting system which usually comes with the firearm made of metal with no optics.
ISOSCELES STANCEA shooting stance in which the gun is held thrust straight out from of the body, with both arms straight.
JACKETThe envelope enclosing the core of a bullet.
JAMA malfunction which locks up the gun so badly that tools are required in order to fix it. Sometimes used to denote a simple malfunction, but many people make a distinction between a complete jam and a simple malfunction.
KEYHOLEAn oddly-shaped hole in the target caused by a bullet which was unstable during its flight and entered the target sideways rather than nose-on. Key-holing sometimes can indicate a safety issue such as using the incorrect caliber for the gun.
KICKSlang for Recoil.
LANDSRaised portions of the bore left between the grooves of the rifling in the bore of a firearm. The portion of the bore in a rifled barrel (see rifling) that protrudes into the bore itself. The top surface of the lands is approximately the same diameter as the bore was prior to rifling.
LASERA laser is an alternative sighting device which enables the shooter to quickly and accurately see where the firearm is aimed even when lighting or other conditions prevent using the gun’s normal sights. Lasers may be located within the grips, hung from accessory rails at the front end of the gun, or placed within the firearm.
LASER GRIPA grip which contains a pressure-activated laser pointer which enables the shooter to quickly and accurately see where the firearm is aimed even when lighting or other conditions prevent using the sights.
LCLong Colt, a type of ammunition.
LEADTo aim at a spot just in front of a moving target, so that the target moves into the line of fire as the trigger is pulled.
LEADThe metal from which bullets are traditionally made. They may also be made of steel, copper, or other materials.
LENGHT OF PULL1) The distance between the face of the trigger and the rearmost surface of the gun.
2) The distance the trigger must travel before it fires the gun.
LEVER-ACTIONA rifle mechanism activated by manual operation of a lever. The user manually brings this lever down and back up again to eject the spent case and bring a new round into the chamber ready to be fired.
LIGHT DOUBLE ACTION (LDA)A double-action semi-automatic firearm which is designed to have a much lighter trigger pull than is usual for a double action.
LIMP WRISTINGA floppy, limp wrist while shooting.
LOADEDA firearm is loaded when a cartridge is in its firing chamber. However, for safety reasons all firearms are always treated as loaded at all times. See The 4 Rules.
LOADED CHAMBER INDICATORA mechanical device that protrudes from the gun when a round is in position ready to be fired, giving a visual and tactile indication that the gun is loaded. Loaded chamber indicators are required by law in some states.
LONG GUNA firearm with an extended barrel, designed to be fired while in contact with the shoulder of the shooter and include rifles and shotguns.
LONG TRIGGERA trigger with an exceptional length of pull.
LOW KNEELINGA shooting position in which one or both knees are touching the ground and the shooter is as low as possible.
LONG RECOILA semi-automatic pistol in which the barrel and breechblock are locked together for the full distance of rearward recoil travel, after which the barrel returns forward, while the breechblock is held back. After the barrel has fully returned, the breechblock is released to fly forward, chambering a fresh round in the process.
LRLong Rifle, a type of ammunition.
MACHINE GUNA fully automatic firearm that rapidly fires multiple rifle-caliber shots with a single pull of the trigger.
MACHINE PISTOLA fully automatic Small Arm using a cartridge designed and intended for use in pistols. Commonly called a “submachine gun.”
MAGAZINEA container, either fixed to a pistol’s frame or detachable, which holds cartridges under spring pressure to be fed into the gun’s chamber. Detachable magazines for the same gun may be offered by the gun`s manufacturer or other manufacturers with various capacities. A gun with a five-shot detachable magazine, for instance, may be fitted with a magazine holding 10, 20, or 50 or more rounds. Box magazines are most commonly located under the receiver with the cartridges stacked vertically. Tube or tubular magazines run through the stock or under the barrel with the cartridges lying horizontally. Drum magazines hold their cartridges in a circular mode. A magazine can also mean a secure storage place for ammunition or explosives.
MAGAZINE DISCONNECTSometimes called a magazine safety. A mechanism that prevents the gun from being able to fire when the magazine is removed from the gun, even if there is still a round in the chamber. Magazine disconnects are required by law in some states.
MAGAZINE LOADERA mechanical device to make it easier to fill magazines using less hand strength and without hurting one’s fingertips or thumbs.
MAGAZINE POUCHCommonly shortened to mag pouch, this is a device to hold extra magazines which fastens to the shooter’s belt.
MAGAZINE WELLThe opening in the bottom of the gun into which a box magazine is fed. On a semi-auto handgun, the magazine well is at the base of the grip; on a rifle, it is usually placed in front of the trigger guard.
MAGNUM A term indicating a relatively heavily loaded metallic cartridge or shotshell and a gun safely constructed to fire it. It generally indicates a round which cannot be interchanged with other loadings of the same caliber (for example, a .22 Magnum shell does not fit within a firearm designed to fire .22 Long Rifle ammunition).
MAINSPRINGTerm often used for the hammer spring.
MALFUNCTIONA misfeed or other failure to fire which can be cleared on the spot and without tools.
MANUAL SAFETYA safety which the shooter must deliberately disengage in order to fire the gun. The most common form of safety mechanism is a switch that, when set to the “safe” position, prevents a pull of the trigger from firing the firearm.
MASTER MARKSMANA person who can shoot up to the mechanical capability of their weapon.
MATCH GRADEA higher quality item used to increase accuracy — generally used for competition in a match. Match grade ammo and barrels are the most common improvements made to a firearm to improve accuracy for competition.
MINUTE OF ANGLE (MOA)A unit of angle that is equal to one 1/60 of one degree. Used to adjust sight angles to aim a firearm.
MISFEEDIs a failure of the next round to completely enter the chamber. Misfeeds and failures to feed are very similar, a failure to feed is a round that never even leaves the top of the magazine, while a misfeed is a round that leaves the magazine but does not enter the chamber.
MISFIREThe condition of a cartridge not firing when an attempt to fire it is made. It can be caused by either a defective cartridge or a defective firearm. The term is frequently misused to indicate a Negligent Discharge of a firearm.
MOON CLIPA flat, circular loading device for revolvers and is designed specifically for rimless cartridges (such as 9mm Luger or .45 ACP), and it becomes an integral part of the revolver while firing.
MOUSE GUNA name for any palm sized handgun which fires a small caliber.
MUFFSHearing protection which completely covers both ears and is usually attached to a headband (sometimes to a neckband rather than a headband).
MULTI-BARRELEDA gun with more than one barrel, the most common being the double-barreled shotgun.
MUSHROOMED BULLETA description of a bullet whose forward diameter has expanded after penetration.
MUSKETA long gun which has a completely smooth bore and is intended to fire a single projectile rather than a collection of shot. Muskets were common before rifles were invented, but now they are mostly collector’s items.
MUZZLEThe open end of the barrel from which the projectile exits.
MUZZLE CONTROLBeing aware of and responsible of which direction your firearm is pointed at all times, and always keeping it pointed in a safe direction.
MUZZLE BRAKEAn attachment to or integral part of the barrel that redirects some of the pressurized gas that propelled the bullet out the muzzle to the sides and possibly rearwards from the direction of the bullet travel. This reduces the recoil of the firearm.
MUZZLE FLASHA muzzle flash is the visible light of a muzzle blast, which expels high temperature, high pressure gases from the muzzle of a firearm. The blast and flash are caused by the combustion products of the gunpowder, and any remaining unburned powder, mixing with the ambient air. The size and shape of the muzzle flash is dependent on the type of ammunition being used and the individual characteristics of firearm and any devices attached to the muzzle (such as a muzzle brake or flash suppressor)
MUZZLELOADERThe earliest type of gun, now also popular as modern-made replicas, in which blackpowder and projectile(s) are separately loaded in through the muzzle. The term is often applied to cap-and-ball revolvers where the loading is done not actually through the muzzle but through the open ends of the cylinder`s chambers.
MUZZLE VELOCITYThe speed of the bullet, measured in feet per second or meters per second, as it leaves the barrel.
NEGLIGENT DISCHARGE (ND)The unplanned discharge of a firearm caused by a failure to observe the basic safety rules, not a mechanical failure of the gun. See The 4 Rules.
NFA 34 (NATIONAL FIREARMS ACT OF 1934)The set of federal regulations that govern the sale and possession of certain classes of firearms. It among other things:
Requires the registration of all fully automatic firearms.
Requires the registration of all “sawed off” rifles and shotguns.
Requires the registration of firearm silencers.
Imposes a $200 transfer tax on the above items.
Regulates the sale, manufacture, transfer, and transportation of the above items.
NIGHT SIGHTS A type of iron sights that glow or shine in the dark, intended for use in low light conditions. Some night sights consist of tiny tubes of tritium, while others use a phosphorus paint
NRAhe National Rifle Association. This organization coordinates shooting events on a national level, provides firearms training to civilians and law enforcement, fights restrictive firearms legislation and supports the constitutional right of law abiding citizens to own and carry firearms.
OFF HAND1) means to shoot while standing and without bracing against anything. It also means the non-dominant hand.
OGIVEA type of curve represented by the curved section of a bullet between its bearing surface and its tip.
OPEN BOLT FIRING (SYSTEM)A type of firearm in which the action is in the open position and the chamber empty prior to firing. When the trigger is pressed the bolt moves forward, chambering a cartridge and firing it and returning to the open position. When firing is stopped the bolt remains open and the chamber empty. Most submachine guns utilize this type of action.
OPEN FRAMERefers to a revolver frame that has no top-strap over the cylinder.
OPEN SIGHTSA common type of iron sights in which the rear sight is an open-topped U or a V or a square-notch shape and with a blade type front sight, in contrast to the closed circle commonly found in aperture sights.
OTM (Open Tip Match) BulletA rifle projectile made with the tip of the bullet open as a means of increasing accuracy as compared to standard military bullets that are made with a closed tip and an open base. The are not designed to expand like a hollow point bullet but may fragment.
OUT OF BATTERYA semi-automatic is said to be out of battery when the slide fails to come all the way forward again after the gun has fired. This condition can be created by a misfeed, a dirty gun, weak springs, the shooter’s thumbs brushing against the slide, riding the slide, or any of several other causes.
OVER/UNDERA shotgun with two barrels that are vertically aligned with each other, one on top of the other.
OVERSHOOT (TO)A term used in artillery to indicate a projectile impact beyond the designated target.
OVER TRAVEL If the trigger is able to continue moving to the rear after the shot has fired, the trigger is said to over-travel.
OVERBORE CAPACITYIs that combination of caliber, barrel length, bullet weight, and case volume which does not allow the complete burning of the charge of ballistically correct powder within the volume of case and barrel.
P+ AMMUNITIONIs small arms ammunition that has been loaded to a higher internal pressure than standard for it’s caliber. Many calibers are available in both standard and +p or +p+ variants. Ammunition marked +p produces more power and higher pressures than the standard ammunition. Not all firearms are designed to handle the increased pressure consult your owner’s manual or gun manufacturer before using +P ammunition.
PAIRTwo shots fired very quickly with the use of the sights.
PARALLAXThis occurs in telescopic sights when the primary image of the objective lens does not coincide with the reticle.Telescopic sights often have parallax adjustments to minimize this effect.
PASSIVE SAFETYAny safety, internal or external, which functions apart from the shooter’s conscious control. Grip safeties are one example of a passive external safety.
PATTERNA shotgun term which refers to the manner in which the pellets spread out as they exit the gun. THE pattern refers to the overall shape of the entire set. A tight pattern is one in which the pellets are closely grouped when they land on target. A loose pattern is one in which the pellets are widely spread.
PEEP SIGHTAn alternate name for Aperture Sight.
PELLET GUNA rifle or pistol using compressed air or CO2 to propel a skirted pellet as opposed to a spherical BB. Not a firearm.
PELLETSSmall spherical projectiles loaded in shotshells and more often called “shot.” Also the skirted projectiles used in pellet guns.
PISTOLSynonymous with “handgun.” A gun that is generally held in one hand. It may be of the single-shot, multi-barrel, repeating or semi-automatic variety and includes revolvers.
PISTOL GRIPAn extra handle behind the trigger for the firing hand to wrap around. A “semi-pistol grip” is one less pronounced than normal; a “vertical pistol grip” is more pronounced than normal.
PLINKINGInformal shooting at any of a variety of inanimate targets. The most often practiced shooting sport in this country.
POINT SHOOTINGShooting without using the sights. Point shooters use body position or other cues to provide a a sense of where the shots will land.
POINT BLANK RANGEThe farthest distance that a target of a given size can be hit without holding over or under with the sights. The exact range is determined by the performance of the cartridge used, the ZERO range, and the accepted size of the target area.
PORTAn opening. The ejection port is the opening in the side of a semi-auto from which spent cases are ejected.
PORTINGOpenings at the muzzle end of the gun through which some of the spent gases can escape. Porting reduces perceived recoil and lessens muzzle rise but increases the noise and flash.
POWDERThe chemical propellant which is burned to produce the hot gases which send the bullet flying downrange.
PRE-TRAVELSome triggers can be pulled slightly backwards before the shooter can feel any tension and before the hammer or striker begins to retract. Pre-travel is any movement of the trigger that begins before the trigger starts to engage.
POWDER CHARGEThe amount of propellant powder that is suitable for specific cartridge-bullet combination, or in the case of shotshells, for a specific weight of shot and wad column.
PRACTICAL SHOOTING A shooting sport that simulates the use of a small arm in its intended role either as a tool for hunting or personal defense. True practical shooting limits the small arms, ammunition, and accessories used to those items that would actually be used in the role simulated.
PRIMERA small metal cup that contains a tiny explosive charge that is sensitive to impact. A primer is placed in the base of a shell casing to ignite the powder of the completed cartridge. It is detonated by the striking of a firing pin in the firearm.
PRIMER POCKETThe counter bore in the center of the base of a centerfire cartridge casing in which the primer assembly is seated.
PRIMER RINGRefers to a visible dark ring created by the primers in centerfire ammunition around the firing pin hole in the frame after much use.
PRINTINGIs when the outline of the concealed handgun may be discerned through the outer clothing.
PROPELLANTIn a firearm the chemical composition that is ignited by the primer to generate gas. In air or pellet guns, compressed air or CO2.
PULL1) The entire process of making the trigger complete its journey past the trigger break. 2) What a shotgun shooter yells when she wants a target (typically a clay pigeon) to be thrown into the air to shoot.
PULL DISTANCEThe distance the trigger must travel before it reaches the break point and fires the gun.
PUMP ACTIONPump or Pump Action – A type of mechanism for removing a spent shell casing from the chamber of a firearm and inserting a fresh cartridge into the chamber. This type of mechanism is most commonly used in shotguns and rimfire rifles.
PYRODEXA trade name for a blackpowder substitute, the only such safe substitute known at this time.
RACKING THE SLIDEpulling the slide back to its rearmost position, and then letting it go forward under its own spring tension. Racking the slide loads the chamber and prepares the gun to fire in a semi-automatic handgun.
RAILA feature on the underside of the frame below the barrel which allows various aftermarket accessories to be attached the firearm such as flashlights or lasers.
RAILSThe metal surfaces upon which a semi-automatic’s slide travels to and fro as each shot is fired.
RANGE FINDERA device used to determine the range to a target. Many range finders work by bouncing a laser beam off the target or nearby object and measuring the time for the reflection to arrive back at the instrument. It is also possible to use various passive optical devices such as a mil-dot telescopic sight.
REACHThe measurement from the backstrap to the face of the trigger.
REACTIVE TARGETSTargets that do something when you hit them, such as fall over, burst, send up smoke, or make a noise.
REAR SIGHTThe rear sight is placed at the end of the barrel nearest the shooter. It may be in the shape of a square notch, a U, a V, a ring, or simply two dots designed to be visually placed on either side of the front sight while shooting.
RECEIVERThe housing for a firearm’s breech (portion of the barrel with chamber into which a cartridge or projectile is loaded) and firing mechanism. In semi-automatic handguns and revolvers, this part is typically called the frame.
RECOILSometimes called kick, is the sudden rearward push made against the shooter when a firearm is fired. This push is due to Newton’s Third Law of physics (for every action there is an equal and opposite reaction). The heavier the bullet and the faster it leaves the muzzle of the barrel the more recoil. A shooter is said to be recoil sensitive if she does not enjoy the sensation caused by this rearward force.
RECOIL-OPERATEDRefers to a semi-automatic pistol whose barrel and breechblock both recoil rearward in reaction to the discharging bullet. See “Short recoil” and “Long recoil”.
RECOIL SPRINGThe recoil spring is the powerful spring that cushions the slide in its rearward travel and then sends the slide forward again with enough force to drive the fresh round firmly into the chamber. The strength of the recoil spring is calibrated to run the slide without any outside assistance.
See also: riding the slide.
RED DOT SIGHTAn optical sight that uses an internal illuminated dot (normally red in color) as an aiming point.They provide for fast target acquisition. They may or may not offer magnification.
REGISTRATIONA method by which a gunsmith makes all the slots of the screws in a firearm line up. Usually this involves such things as machining a new slot in the screw.
RECEIVERThe portion of a rifle that has the serial number on it. The stock, barrel, and other components such as the bolt are typically attached to the receiver. Some firearms may have a multipart receiver such as an upper receiver and a lower receiver.
REGULATEDouble barreled guns need to be adjusted so both barrels shoot to the same point of aim at some particular distance.
RELOAD1) To refill the firearm with ammunition in order to continue shooting.
2) When a shooter reuses empty brass cases and fills them with new primers, powder, and bullets.
REPEATING FIREARMA firearm that may be discharged repeatedly without recharging by means of deliberate, successive mechanical actions of the user.
RESETThe point of the trigger’s return at which the gun’s internal mechanisms are ready to fire another round.
RETICLETypically crosshairs or a dot that are seen in the center of a firearm scope that assists the rifleman in aligning the shot, that is adjusted so that it appears to be on the same plane as the target.
REVOLVERA gun, usually a handgun, with a multi-chambered cylinder that rotates to successively align each chamber with a single barrel and firing pin.
RIDING THE SLIDERacking the slide incorrectly by allowing your hand to rest upon the slide as it moves forward during the loading procedure. Riding the slide is a common cause of misfeeds and other malfunctions.
RIFLEA firearm designed to be fired from the shoulder and fire only a single projectile at a time, as opposed to a shotgun which can throw many small projectiles (shot) at the same time.
RIFLINGSpiral grooves in a gun`s bore that spin the projectile in flight and impart accuracy. Rifling is present in all true rifles, in most handguns and in some shotgun barrels designed for increasing the accuracy potential of slugs (a slug is a single projectile rather than the more common “shot”.)
RIGHT TO BEAR ARMSThe unalienable right of all of the people, stated in the Second Article of The Bill of Rights, to possess and use personally owned firearms for sport, recreation, personal protection, and the defense of the nation.
RIMFIREA rimfire is a type of firearm cartridge. It is called a rimfire because instead of the firing pin of a gun striking the primer cap at the center of the base of the cartridge to ignite it (as in a centerfire cartridge), the pin strikes the base’s rim. A rimmed or flanged cartridge with the priming mixture located inside the rim of the case. The most famous example is the .22 rimfire.
RIMLESSA cartridge in which the base diameter is the same as the body diameter. The casing will normally have an extraction groove machined around it near the base, creating a “rim” at the base that is the same diameter as the body diameter.
RIOT GUNA popular term for a short barreled repeating shotgun as frequently used in law enforcement and personal protection.
ROUNDSynonym for a cartridge. A unit of measure for ammunition which is one complete unit of ammunition, which includes a bullet (or other projectile), powder, and a primer, and is contained in an outer shell or case. Typical quantities are 20 rounds and 50 rounds in single box.
ROUGH TRIGGERA trigger which has a gritty or inconsistent feel during the pull.
ROUND GUNSlang term for a revolver.
ROUND NOSEThe classic bullet shape.
RUNNING THE GUN Performing all necessary manipulations (such as loading, unloading, or clearing jams) to keep the firearm functioning as designed.
SABOTA lightweight carrier surrounding a heavier projectile of reduced caliber, allowing a firearm to shoot ammunition for which it is not chambered. For example, a hunter could use his .30-30 deer rifle to shoot small game with .22 centerfire bullets.
SAFE1) A firearm is said to be on safe when its safety is engaged and off safe when it is ready to fire. Always follow the Four Rules even when the safety is engaged.
2) A locking container in which firearms are stored when not in use.
SAFETYConscientiously following the Four Rules every single time you handle a firearm.
SAFETY (MECHANICAL)A mechanical device used to block the firing pin or trigger such that the firearm cannot be fired.
SATURDAY NIGHT SPECIALA catchy phrase having no legal or technical meaning.
SAWED-OFF SHOTGUN (RIFLE)Common term for federally restricted “short-barreled shotgun (rifle)” as with a conventional shotgun with barrel less than 18″ (rifle less than 16″) or overall length less than 26.”
SCATTERGUNA casual term for a shotgun.
SCOPEA magnifying tube through which the shooter may see the target and aim the firearm. Scopes contain a reticle, commonly in the shape of a cross, which must be properly centered upon the target for accurate aim.
SEARThe part of the trigger mechanism which holds the hammer or striker back. Pressure on the trigger causes the sear to release the hammer or striker, allowing it to strike the firing pin and discharge the weapon.
SECOND AMENDMENT (THE)The second article in the United States Bill of Rights which states, “A well regulated militia being necessary for a free state, the right of the people to keep and bear arms shall not be infringed.”
SELECTIVE-FIREA firearm’s ability to be fired fully automatically, semi-automatically or, in some cases, in burst-fire mode at the option of the firer.
SEMI-AUTOMATIC A firearm designed to fire a single cartridge, eject the empty case and reload the chamber each time the trigger is pulled. It uses the energy from the fired shot to eject the empty case and feed the next round into the chamber.
SEMI-WADCUTTER (SWC)A bullet design featuring a conical extended nose, with a flat point, and a sharp edged shoulder that serves to cut a full diameter hole in the target. This design also may be found with a hollow point to facilitate expansion. A modified wadcutter bullet design with slightly sloping edges, designed to load smoothly in a semi-automatic pistol.
SHELLAn empty ammunition case.
SHELL CASINGA hollow, piece of metal that is closed on one end except for a small hole which holds a primer. The open end holds the bullet. The hollow portion holds the powder. Together the assembled unit is called a cartridge.
SHELL, SHOTGUNThe cartridge for a shotgun. It is also called a “shell,” and its body may be of metal or plastic or of plastic or paper with a metal head. Small shotshells are also made for rifles and handguns and are often used for vermin control.
SHOOTING SPORTSThere are a lot of different competitions and other games which involve firearms. These are all referred to collectively as the shooting sports.
SHORT RECOILA semi-automatic pistol in which the barrel and breechblock are locked together for only a short distance of rearward recoil travel, at which point the two are uncoupled, the barrel is stopped and the breechblock continues rearward, extracting the spent casing from the chamber. Upon returning forward, the breechblock chambers a fresh round and forces the barrel back into its forward position. Most modern recoil operated semi-automatic pistols use short recoil.
SHORT TRIGGERA trigger that doesn’t have to travel very far before it reaches the break. In a 1911 semi-auto pistol, a short trigger is a different part than a long trigger, and (in addition to providing less motion) it features a shorter reach which may be of benefit to a small-handed shooter.
SHORT-STROKINGOn a pump-action firearm, being too gentle with the fore-end and either not pulling it all the way back at the beginning of the stroke, or not shoving it all the way forward at the end of the stroke. Which may result in the old case or shell failing to eject and a misfeeds, or the gun will not fire when the trigger is pulled. The term is used most often to refer to pump-action shotguns, but it is possible to similarly short-stroke any type of firearm which requires the user to manually cycle the action (lever action rifles, for example).
SHOTIn shotgunning, multiple pellets contained in the shell and sent downrange when the shotgun is fired.
SHOTGUNA smooth bore long gun that shoots a group of pellets called shot instead of bullets. Depending on the bore size and the size of the pellets there may be from less than 10 to two hundred or more pellets in a single shotgun cartridge. Shotguns are designed for shooting moving targets (such as flying birds or running rabbits) at close range
SHOTSHELLThe cartridge for a shotgun. It is also called a “shell,” and its body may be of metal or plastic or of plastic or paper with a metal head. Small shotshells are also made for rifles and handguns and are often used for vermin control.
SHOULDERTo bring the butt of a long gun’s stock to the shooter’s shoulder, preparatory to firing the gun.
SIDE-BY-SIDEA shotgun with two barrels which are situated next to each other.
SIGHTSThe device that aids the eye in aiming the barrel of a firearm in the proper direction to hit a target.They can be a mechanical, optical, or electronic device. Iron sights or sometimes as open sights, consist of specially-shaped pieces of metal placed at each end of the barrel. The sight closest to the muzzle end of the gun is called the front sight, while the one farthest from the muzzle (and nearest to the shooter) is called the rear sight.
SIGHT ALIGNMENTThe manner in which the sights are lined up properly in front of the shooter’s eye, to form a straight path to the target.
SIGHT PICTUREWhat the shooter sees when looking through the sights at the target.
SIGHT RADIUSThe distance between the rear sight and the front sight.
SIGHT, FRONTThe front sight is placed at the muzzle end of the barrel. It is often (but not always) in the form of a dot or a blade. To attain a proper sight picture and shoot with the greatest degree of accuracy, the shooter’s eye should be focused sharply upon the front sight while shooting, allowing both the rear sight and the target to blur somewhat.
SIGHT, REARThe rear sight is placed at the end of the barrel nearest the shooter. It may be in the shape of a square notch, a U, a V, a ring, or simply two dots designed to be visually placed on either side of the front sight while shooting.
SILENCERProperly called a suppressor this highly regulated device is used to reduce the sound of a firearm’s discharge.They do not actually silence most firearms but rather lower the intensity of the muzzle blast and change the sound characteristics. The possession, use, and transportation of silencers have been tightly controlled under federal law since 1934. Any device which reduces the sound of discharge by more than 2 dB is considered by the BATF to be a “silencer.”
SILHOUETTE SHOOTINGA handgun or rifle shooting sport in which the competitors attempt to knock over metallic game-shaped targets at various ranges.
SINGLE – ACTION (SA)A pistol or revolver, in which the trigger is only used for firing the weapon, and cannot be used to cock the firing mechanism. On single-action revolvers, the hammer must be manually drawn back to full cock for each shot. On pistols, the recoil action will automatically re-cock the hammer for the second and subsequent shots. A single-action semi-automatic firearm has a hammer that is not actuated by the trigger. The hammer may be cocked by hand, or by racking the slide, or by the rearward movement of the slide after each shot is fired. The most widely known single-action semi-auto handgun is the 1911-style pistol designed by John Moses Browning
SINGLE-SHOTA gun mechanism lacking a magazine where separately carried ammunition must be manually placed in the gun’s chamber for each firing.
SLACKTo ‘take up the slack’ means to pull the trigger through its pre-travel stage.
SKEET A shotgun shooting sport in which the competitors attempt to break aerial targets directed toward them or crossing in front of them from different angles and elevations. It is an Olympic shooting sport.
SLIDEThe upper portion of a semi-automatic pistol that houses the barrel and contains the breechblock and portions of the firing mechanism. Ejecting the spent case as it moves to the rear and loading a fresh cartridge into the chamber as it moves forward again. As its name states, it slides along tracks in the top of the frame during the recoil process providing the linkage between the breechblock and barrel.To rack the slide means to pull the slide back to its rearmost position, and then let it go forward under its own spring tension. To ride the slide means to rack the slide incorrectly, allowing your hand to rest upon the slide as it moves forward during the loading sequence. Riding the slide is a common cause of malfunctions.
SLIDE-ACTIONA gun mechanism activated by manual operation of a horizontally sliding handle almost always located under the barrel. “Pump-action” and “trombone” are synonyms for “slide-action.”
SLIDE LEVERTypically refers to a lever either on the left or right side of a pistol’s frame that is used to release the slide for removal, maintenance and cleaning.
SLIDE LOCKWhen most semi-automatic firearms have been fired until its magazine is empty, the slide will remain in its rearmost position and lock open. This condition of the gun is called slide lock.
SLIDE RELEASEThe slide release lever is usually located on the left side of the slide, and is pushed down to unlock the slide and release it to move forward into its normal position. It is sometimes called the slide stop or slide stop lever.
SLING A long strip of leather, plastic, or nylon which is fastened at the fore and rear of the gun for the easy carry of long guns.
SLUGMore correctly a “rifled slug” or “shotgun slug.” An individual cylindrical projectile designed to be discharged from a shotgun. The term is often incorrectly used to mean a Bullet.
SLUG-GUNSlang for a shotgun which is set up specifically to fire a slug (a large, single projectile) rather than shot (multiple projectiles contained within a single shell).
SMALL ARMSFirearms designed to be carried and used by an individual or individuals.
SMOKELESS POWDERThe propellant powder used in modern ammunition. It is not an explosive, but rather a flammable solid that burns extremely rapidly releasing a large volume of gas. Commonly called “gunpowder” and usually made from nitrocellulose, or nitrocellulose and nitroglycerin. It is classified as a “Flammable Solid” by the Department of Transportation.
SMOOTH BOREA barrel without rifling. Smooth bore barrels are commonly used in shotguns and in large bore artillery that fire fin stabilized projectiles.
SNAP-CAPAn inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions. Some folks also use them during dry fire practice to cushion the firing pin as it strikes.
SNIPERA military person designated as a special marksman who is used to shoot designated targets of opportunity at long range.
SNIPER RIFLEA specialized, highly accurate rifle, fitted with an optical sight used by military snipers to engage personnel and hard targets at long range.
SNUBBYCasual slang for a short-barreled revolver.
SNUB-NOSEDDescriptive of (usually) a revolver with an unusually short barrel.
SPEED STRIPA flat piece of rubber which holds revolver cartridges preparatory to loading them into the revolver’s cylinder.
SOFT POINTA metal jacketed bullet design in which the nose of the core of the bullet is exposed to ensure the expansion of the bullet upon impact. Often abbreviated “JSP” or “SP.” They tend to expand more slowly than a Hollow Point bullet and are used where deeper penetration and expansion are needed.
SPEED LOADERn revolvers the speed loader is a circular device or clip that holds a complete set of cartridges and are aligned to insert into all chambers of the cylinder simultaneously.
SPOTTERThe spotter is a helper who gives the shooter guidance on how to hit a particular target. In some cases the spotter may just report the location of the bullet impact. In other cases they may judge the speed and direction of the wind, determine the range, and give the shooter the settings to be used on the sights.
SPORTING CLAYSA shotgun shooting sport that combines elements of skeet and trap, and that is designed to simulate field conditions.
SPORTING FIREARMAny firearm that can be used in a sport.
SPRAY AND PRAYA term often used to refer to the very poor and dangerous practice of rapidly firing many shots at a target as possible in the hope that one or more may hit the target. This practice is a danger not only to bystanders but also to the shooter.
SQUIBA round of ammunition which has less power than it is supposed to, often having no powder at all. Squib loads are very uncommon when shooting commercial ammunition.
STANCEHow the shooter positions her body while shooting. The three most widely-known handgun stances are Weaver, Chapman, and Isosceles.
STOCK1) The back part of a rifle or shotgun, excluding the receiver. It is commonly made of wood, wood laminate, metal, or plastics. 2) An unaltered firearm as it comes from the factory. 3) Some people and companies refer to handgun grip panels as stocks.
STOVEPIPEFailure of a spent case to completely eject from a semi-automatic firearm. The case usually stands on end while lodged in the ejection port.
STRIKERIn a handgun that does not have a hammer, the striker is a linear driven, spring loaded cylindrical part which strikes the primer of a chambered cartridge. The striker replaces both the hammer and firing pin found in hammer driven pistols.
STRIPPER CLIPSimple clips made of metal or sometimes plastic that hold several rounds of ammunition in a row and is used to quickly fill a magazine.
STOPPING POWERA popular but imprecise term used to refer to the ability of a small arms cartridge to cause a human assailant or an animal to be immediately incapacitated when shot with it. A more precise term is be Wound Trauma Incapacitation (WTI).
SUPPRESSOR, SOUNDImproperly called a “silencer” this highly regulated device is used to reduce the sound of a firearm’s discharge.They do not actually silence most firearms but rather lower the intensity of the muzzle blast and change the sound characteristics. The possession, use, and transportation of silencers have been tightly controlled under federal law since 1934. Any device which reduces the sound of discharge by more than 2 dB is considered by the BATF to be a “silencer.”
TANGEThe recurved top part of a semi-automatic handgun’s grip at the point where it meets the slide. On long guns, the tang is the top strap used to screw the receiver to the stock.
TAP, RACK, BANGThe slang term for the procedure to clear a misfeed. To clear a misfeed, tap the base of the magazine firmly to be sure it is properly seated, rack the slide to eject an empty case or feed a new round, and assess to be sure your target still needs shooting. If it does, pull the trigger to create the bang.
TEFLONTrade name for a synthetic sometimes used to coat hard bullets to protect the rifling. Other synthetics, nylon for instance, have also been used as bullet coatings. None of these soft coatings has any effect on lethality.
TELESCOPIC SIGHTA sight which has an integral telescope.
THUMB SAFETYAn external, manual safety which is typically disengaged with the firing-hand thumb.
TOE (OF A STOCK)The bottom of the butt, when the gun is in position on the shoulder to be fired, is called the toe
TOPSTRAPThe part of a revolver frame that extends over the top of the cylinder and connects the top of the standing breech with the forward portion of the frame into which the barrel is mounted.
TOTAL METAL JACKETA type of bullet in which the lead core is encased in a copper jacket on the front and sides.
TRACEVisible disturbance in the air by a bullet. Typically this takes the form of image distortion that persists for a fraction of a second in the shape of an inverted V similar to that of a boat wake.
TRACER (AMMUNITION)A type of ammunition that utilizes a projectile or projectiles that contain a compound in its base that burns during its flight to provide a visual reference of the projectile’s trajectory.
TRAJECTORYThe arc described by a projectile traveling from the muzzle to the point of impact.
TRAPA shotgun shooting sport in which the competitors attempt to break aerial targets going away from them at different angles and elevations. It is an Olympic shooting sport. The term can also refer to the device used to throw the targets.
TRIGGERThe release device that initiates the cartridge discharge. Usually a curved, grooved or serrated piece that is pulled rearward by the shooter’s finger, which then activates the hammer or striker and the gun fires.
Typically, pulling the trigger releases the striker or allows the hammer to fall, causing the firing pin to strike the primer. The primer then ignites the powder within the round. Burning gases from the powder force the bullet out of its case and through the barrel, causing the bullet to exit the muzzle end of the gun and strike the target. In addition to releasing the hammer or striker, some triggers may cock the hammer or striker, rotate a revolver’s cylinder, deactivate passive safeties, or perform other functions.
TRIGGER BAROn a semi-automatic pistol, or any other firearm in which the trigger is at some distance from the sear, this is an intermediate piece connecting the two parts.
TRIGGER CONTROLNot putting your finger on the trigger until your sights are on target, then pulling the trigger smoothly, and following through by realigning the sights before allowing your finger to come off the trigger.
TRIGGER GROUPThe entire collection of moving parts which work together to fire the gun when the trigger is pulled. It may include trigger springs, return springs, the trigger itself, the sear, disconnectors, and other parts.
TRIGGER GUARDUsually a circular or oval band of metal, horn or plastic that goes around the trigger to provide both protection and safety in shooting circumstances. The shooter’s finger should never be within the trigger guard unless the sights are on target and the shooter has made the decision to fire.
TRIGGER JERKYanking the trigger back abruptly, thus pulling the muzzle of the gun downward at the moment the shot fires.
TRIGGER LOCK A locking device put on a firearm to render it unable to be fired. This can be useful in a home which does not have a gun safe and has small children.
TRIGGER PULLThe entire process of moving the trigger from its forward-most position to its rearward-most position, causing the hammer to fall and the shot to fire.
TRIGGER PULL WEIGHTHow much pressure the trigger finger must put on the trigger before the gun will fire. Trigger pull weight is measured by the number of pounds and ounces of pressure required to pull the trigger past the break.
TRIGGER SAFETYAn external, passive safety which can be found on the face of some trigger designs (most notably found on Glock firearms). It is intended to prevent the trigger from being pulled by objects which find their way into the trigger guard area.
TRIGGER SCALEA specialized type of hanging scale designed to test trigger pull weight.
TRIGGER SLAPAn uncomfortable sensation caused by the trigger springing back into the shooter’s trigger finger while firing.
WADA felt, paper, cardboard or plastic disk that is used in a shotshell. Also in muzzle loading, a piece of cloth used to seal the bullet in the barrel. Its purpose and function is the same as a shotgun wad.
WADCUTTER (WC)A bullet designed with a full diameter flat point. It is primarily used in target competition because it cuts a clean round hole in paper targets that aids in scoring the target.
WCF Winchester Centerfirea type of ammunition.
WAITING PERIODA legally mandated delay between the purchase of a firearm and its delivery to the customer enforced in some jurisdictions.
WEAPONAny tool that can be used to apply or project lethal force. Webster defines it as “an instrument of offensive or defensive combat.”
WEAVER STANCEA two handed pistol shooting position named after Jack Weaver, a Deputy Sheriff in the 1950s. The body is angled slightly in relation to the target rather than squarely facing it. The elbows are flexed and pointed downward. The strong-side arm pushes out, while the weak hand pulls back. This produces a push-pull tension which is the chief defining characteristic of the Weaver stance.
WHEEL GUNCasual slang for a revolver.
WINDAGEThe setting on the sights used to accommodate the wind or adjust for horizontal errors in the alignment of the sights with the bore of the firearm.
WOUND TRAUMA INCAPACITATIONThe correct technical term for the ability of a projectile to incapacitate an animal or human shot with a firearm. Incorrectly called Stopping Power.
YOUTH RIFLEA short, lightweight rifle. Some are small enough for a young child to easily handle, while others are large enough to perfectly suit teenagers, average-sized adult women, and small-statured adult males.
YOUTH STOCKA short stock, often ideally sized for teenagers, average-sized adult women, and small-statured adult males.
ZEROA firearm is said to be “zeroed in” when its sights have been adjusted so that the bullet will hit the center of the target when the sights are properly aligned upon the center of the target. The farthest distance from a firearm at which the bullet’s path and the point of aim coincide. This term is also used to mean the process of insuring that the sights of a firearm are properly aligned so that where they indicate the bullet will strike is in fact where it strikes