Gun Glossary: Every Term You Could Possibly Need, In One Spot!

Republished with permission from The Well Armed Woman

Ever wanted to know the meaning of a term used in the world of firearms? You shouldn’t have to look any further than the comprehensive list below.

ACP – An 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

ACTION – The 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 DISCHARGE – An 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 STOCK – The 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 TRIGGER – A trigger that can be easily adjusted by the user. Adjustable triggers are common on specialized target-shooting firearms, but rare on self defense firearms.

AIRGUN – Not a firearm but a gun that uses compressed air or CO2 to propel a projectile. Examples: BB gun, pellet gun, CO2 gun.

AMBIDEXTEROUS SAFETY – A manual, external safety which can be easily reached with either hand. Usually one lever on each side of the firearm.

AMMO – Short for Ammunition

AMMUNITION – The “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.

ANTIQUE – By 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 SIGHT – An 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-15 – >is 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 AMMUNITION – A 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.

ARSENAL – A 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.”

ARTILLERY – Large 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 RIFLE – A military firearm which fires a reduced-power rifle round, and can shoot in both fully-automatic and semi-automatic modes.

ASSAULT WEAPON – A 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.

AUTOLOADER – A 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.

AUTOMATIC – A 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.

BALL – Originally a spherical projectile, now generally a fully jacketed bullet of cylindrical profile capped with a round nose.

BALLISTICS – The 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 FINGERPRINT – A 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.

BARREL – The metal tube through which the bullet or shot travels. The barrel serves the purpose of providing direction and velocity to the bullet.

BATTERY – Most 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.

BACKSTOP – Anything that will safely stop a bullet and prevent it from hitting anything else after the target is struck.

BACKSTRAP – A 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 LUG – A mounting point on a small arm that allows a bayonet or other accessory to be attached.

BEAVERTAIL – A 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.

BERM – On an outdoor shooting range, a large pile of dirt that functions as a backstop.

BIATHLON – A 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.

BIPOD – A 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″

BLACKPOWDER – The 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.

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 – A 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.

BLUING – The chemical process of artificial oxidation (rusting) applied to gun parts so that the metal attains a dark blue or nearly black appearance.

BOAT TAIL – A type of projectile that has a tapered base (rear end) that reduces the drag from the air as it travels to its target.

BOLT – The mechanism of some firearms that holds the cartridge in place during the firing process. It must be moved out of the way to load and unload the gun; this action may be manually performed by the shooter pulling back on an exterior knob called the bolt handle and then sending it forward again, or the action may be performed by other moving parts within the firearm. When the user must move the bolt manually, the firearm is called a bolt-action firearm.

BOLT ACTION – A 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.

BORE – The 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 DIAMETER – The 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.

BOTTLENECKED – A 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.

BREECH – That 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 GUN – a firearm in which the cartridge or shell isinserted or loaded into a chamber to the rear portion of a barrel.

BREECH BLOCK – The 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 FACE – That portion of the breech block which touches the cartridge when the breech is closed.

BREECH OPENING – The open rear of the barrel through which cartridges are inserted into the chamber.

BRICK – A 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.

BUCKSHOT – A 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.

BULLET – The 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 VEST – A popular but incorrect term forbullet resistant clothing.

BULLET TRAP – A type of backstop that catches the fired bullet and prevents it from exiting the area. Bullet traps are most commonly used on indoor ranges.

BULLPUP – A 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.

BUTT – The 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 LOCK – A cable with a padlock at the end. It is threaded through the action of the firearm.

CALIBER – The 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.

CAN – Slang 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.

CANT – Tilting 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.

CARBINE – A 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.

CARTRIDGE – A single, complete round of ammunition which includes the case, primer, powder, and bullet

CASE, CASING – The 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-FIRE – A 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 THROAT – This is the area in the barrel that is directly forward of the chamber, which tapers to the bore diameter.

CHARGER- A 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.

CHOKE – A constriction at or near the muzzle of a shotgun barrel that affects shot dispersion.

CLAY PIGEON – Originally, 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.

CLEARING – Unloading a gun and double checking that it is unloaded or fixing a malfunction so that the gun is ready to fire again.

CLICKS – A unit of adjustment for a sight.

CLIP – The 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.

COCK – The 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

COCKED – A 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 BORE – The 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 RANGE – Pistol must be unloaded until it is your turn to shoot

COLLAPSIBLE STOCK – A 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.

COMPENSATOR – Also 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.

CONCEALED – Hidden from view. A handgun is concealed when it is carried in such a manner that is unseen

CONTROLLED PAIR – Two 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.

COVER – Anything an intended victim hides behind that will probably stop a bullet.

COVER GARMENT – Any 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 SIGHTING – is 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-DOMINANT- This means a shooter who is right-handed but left-eyed, or left-handed and right-eyed.

CROSSHAIRS – The cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.

CROWN – The area inside the bore nearest the muzzle. Damage to the crown can severely and adversely affect the firearm’s accuracy.

CYLINDER – A 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 DRUM – On 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.

DECOCKER – On double-action semi-automatic firearms, a lever that mechanically lowers the hammer without firing the gun.

DELAYED BLOWBACK – A 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.

DERINGER – A 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.

DETONATE – To 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) – Is 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 BARREL – A shotgun with two barrels either side by side or one over the other.

DOUBLE FEED – A 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 TAP – Two 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 RANGE – The 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 SAFETY – A 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 FIRING – The 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.

DUD – A round of ammunition that does not fire.

DUMMY ROUND – An inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions and also used in dry fire practice.

EAR PLUGS – hearing protection that fits inside the ear canal.

EARMUFFS – hearing protection that completely covers both ears and is usually attached to a headband

EARS – Slang 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.

EJECTOR – A spring-activated mechanism for the ejection of ammunition or and empty shell casing. On doubles, each barrel has a separate ejector.

EJECTOR STAR – On a revolver, the collective ejector, manually operated through the center of an opened cylinder, when activated, clears all chambers at once.

EJECTION PORT – The opening through which the empty, spent ammunition case is ejected from of a firearm.

EJECTION ROD – The 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 PROTECTION – Ear muff hearing protection that has internal electronics that amplify human voices while excluding all noises louder than a given decibel rating.

ELEVATION – The 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.

EXPLOSIVE – Any substance (TNT, etc.) that, through chemical reaction, detonates or violently changes to gas with accompanying heat and pressure.

EXTRACTOR – A device that withdraws or elevates a fired shell casing from the chamber as the breech mechanism (slide) is opened.

EXTERNAL SAFETY – A safety lever found on the outer surfaces of the firearm and accessible to the user.

EYES – Slang 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 AMMO – Ammunition 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 EXTRACT – A 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 FEED – A 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 FIRE – Any 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.

FIREPOWER – A 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.

FIREARM – A 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 LINE – A line, either imaginary or marked, from which people shoot their firearms down range.

FIRING PIN – A needle like metal part of a modern firearm that gives a vigorous strike to the primer initiating the firing of the cartridge.

FIRING PIN BLOCK – A type of internal safety that prevents the firing pin from moving forward for any reason unless the trigger is pulled.

FIXED AMMUNITION – A complete cartridge of several obsolete types and of today’s rimfire and center-fire versions.

FLASH HIDER/FLASH SUPPRESSOR – A 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.

FLINCH – Jerking 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 STOCK – A long gun stock that may be doubled over for conveniently compact storage.

FOLLOW THROUGH – Holding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.

FOULING – The gritty residue that cleaned out of the barrel and all areas of the firearm in order to clean it.

FOULING SHOT – A 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 RULES – The 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.

FOREND – That 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.

FRAME – The common part of a handgun to which the action, barrel and grip are connected.

FRONT SIGHT – The 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 STRAP – The part of a revolver or pistol grip frame that faces forward and often joins with the trigger guard.

FULL METAL JACKET FMJ –  A type of round in which in which the lead core bullet is encased in a harder metal jacket on the front and sides.

GAP- Glock Auto Pistol, a type of ammunition.

GAS – The superheated air and other stuff produced by burning powder. Gas pressure is what sends the bullet downrange.

GAS OPERATED – The superheated air created by burning powder. A gas-operated firearm is one that uses the energy from these superheated gases to work the action.

GAUGE – The 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 SIGHT – A 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.

GRAINS – A 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 AMMUNITION – Ammunition that contains no lead in any component.

GRIPS – The 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 PANELS – The 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 SAFETY – A 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.

GRIPSTRAPS – The exposed portion of a handgun’s frame, the front strap and backstrap, that provides the foundation for the handgun’s grip.

GROOVES – Spiral 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.

GROUP – A 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.

GUNPOWDER – Chemical 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 TRIGGER – A trigger that breaks from an extremely light touch.

HAMMER – On 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 SPUR – The thumb-piece on the top rear of the hammer that enables it to be manually drawn back to full cock.

HAMMERLESS – A 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.

HANDGUN – Synonym for pistol. designed to be fired while held in one or both hands, rather than while braced against the shoulder.

HANDLOADS – Cartridges assembled by an individual person from the individual components (primer, shell casing, gunpowder, and bullet) and are typically tailored specifically for their firearm.

HARDBALL – Slang 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 TRIGGER – A 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 KNEELING – A shooting position in which one or both knees are touching the ground, but the shooter is otherwise erect.

HMR – Hornady Magnum Rimfire, a type of ammunition.

HOLLOW-POINT BULLET – A 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

HOLSTER – A 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 RANGE – Pistol can be carried loaded, also a range where the range master has given the order to commence fire

INTEGRAL LOCK – A built in lock that may prevent the firearm from being fired

INTERNAL SAFETY – A 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 SIGHTS – The mechanical sighting system which usually comes with the firearm made of metal with no optics.

ISOSCELES STANCE – A shooting stance in which the gun is held thrust straight out from of the body, with both arms straight.

JACKET – The envelope enclosing the core of a bullet.

JAM – A 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.

KEYHOLE – An 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.

KICK – Slang for Recoil.

LANDS – Raised 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.

LASER – A 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 GRIP – A 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.

LC – Long Colt, a type of ammunition.

LEAD – To 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.

LEAD – The metal from which bullets are traditionally made. They may also be made of steel, copper, or other materials.

LENGHT OF PULL – 1) 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-ACTION – A 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 WRISTING – A floppy, limp wrist while shooting.

LOADED – A 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 INDICATOR – A 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 GUN – A firearm with an extended barrel, designed to be fired while in contact with the shoulder of the shooter and include rifles and shotguns.

LONG TRIGGER – A trigger with an exceptional length of pull.

LOW KNEELING – A shooting position in which one or both knees are touching the ground and the shooter is as low as possible.

LONG RECOIL – A 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.

LR – Long Rifle, a type of ammunition.

MACHINE GUN – A fully automatic firearm that rapidly fires multiple rifle-caliber shots with a single pull of the trigger.

MACHINE PISTOL – A fully automatic Small Arm using a cartridge designed and intended for use in pistols. Commonly called a “submachine gun.”

MAGAZINE – A 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 DISCONNECT – Sometimes 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 LOADER – A mechanical device to make it easier to fill magazines using less hand strength and without hurting one’s fingertips or thumbs.

MAGAZINE POUCH – Commonly shortened to mag pouch, this is a device to hold extra magazines which fastens to the shooter’s belt.

MAGAZINE WELL – The 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).

MAINSPRING – Term often used for the hammer spring.

MALFUNCTION – A misfeed or other failure to fire which can be cleared on the spot and without tools.

MANUAL SAFETY – A 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 MARKSMAN – A person who can shoot up to the mechanical capability of their weapon.

MATCH GRADE – A 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 one1/60 of one degree. Used to adjust sight angles to aim a firearm.

MISFEED – Is 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.

MISFIRE – The 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 CLIP – A 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 GUN – A name for any palm sized handgun which fires a small caliber.

MUFFS – Hearing protection which completely covers both ears and is usually attached to a headband (sometimes to a neckband rather than a headband).

MULTI-BARRELED – A gun with more than one barrel, the most common being the double-barreled shotgun.

MUSHROOMED BULLET – A description of a bullet whose forward diameter has expanded after penetration.

MUSKET – A 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.

MUZZLE – The open end of the barrel from which the projectile exits.

MUZZLE CONTROL – Being aware of and responsible of which direction your firearm is pointed at all times, and always keeping it pointed in a safe direction.

MUZZLE BRAKE – An 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 FLASH – A 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)

MUZZLELOADER – The 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 VELOCITY – The speed of the bullet, measured in feet per second or meters per second, as it leaves the barrel.