Accidental Discharge — An unintentional firing of the gun caused by mechanical error (the gun broke). If mechanical error was not the cause, it is almost certainly a negligent discharge (a human error was involved).

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.

Action — A group of moving parts used to load, fire, and unload the firearm.

Adjustable Stock — A stock is the wooden, polymer, or metal part of a long gun that extends generally from the area of the trigger back to where the gun is braced against the shoulder while shooting. An adjustable stock is one that can be easily lengthened or shortened to fit shooters of different sizes.

Adjustable Trigger — A trigger in which one or more parameter may be easily adjusted by the user. The most common adjustment is pull weight, but a fully adjustable trigger may be adjustable for pull distance, individual trigger stage distances, individual trigger stage weights, release point, left/right cant, overtravel, and possibly others. Adjustable triggers are common on specialized target-shooting firearms, but rare on self defense firearms.

Ambidextrous Safety — A manual, external safety which can be easily reached with either hand. It often features dual levers, with one lever on each side of the firearm.

Ammo —

Ammunition — Gun food. Typically, the term refers to the complete package of components the firearm needs in order to fire. This often includes a projectile (the bullet, slug, or pellets), a propellant (the powder), and a primer (which produces the spark that ignites the powder). Shotgun ammunition also includes a wad, which acts as a buffer between the shot and the powder and seals in the gases which propel the shot out of the barrel. Ammunition components are held together within a case (handguns and rifles) or a shell (shotguns).

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. 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. Despite public perception, assault weapons are not machine guns. They are semi-automatic firearms, not fully automatic firearms.

Autoloader — A semi-automatic pistol, shotgun, or rifle.

Automatic — A firearm which rapidly fires multiple shots with a single pull of the trigger. A fully automatic firearm is commonly called a machine gun.

In America, fully automatic firearms have been strictly regulated since 1934, and illegal to produce or import since the 1980s. Functioning full-auto guns legal for civilians to own are extremely difficult to find, and very expensive to purchase, often costing $10,000 or more. Existing fully-automatic firearms are generally antiques. They are illegal for civilians to own in many (but not all) states. In states where fully-automatic firearms are legal to collect, federal law requires the purchase of a $200 authorization stamp for each firearm. An extensive background check, which includes approval of local law enforcement and requires full fingerprints and photographs, is conducted before the purchase is approved.

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.

Ball — Often used in casual conversation to mean any ammunition capped with a roundnose FMJ bullet, especially in .45 ACP caliber, but is more accurately used to describe standard military ammunition of any standard military caliber. Also, a round lead bullet used in muzzle-loading firearms.

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.

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.

Beavertail — On many 1911-style pistols, 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.

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

Birdshot — A type of shotgun ammunition which uses very small pellets. It is so named because it is most often used for hunting birds. Birdshot comes in different sizes. Generally speaking, the smaller the pellets, the more of them there are in each round of ammunition.

Black Powder — Black powder is a type of gunpowder invented in the 9th century and was practically the only known propellant until the middle of the 19th century when smokeless powder was invented. It is purchased separately from other ammunition components, and is commonly used in muzzle-loading firearms. It is not used in modern encased ammunition.

Bolt — A bolt is a mechanical part in some firearms which blocks the rear of the chamber while the powder burns. 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 — An action type most commonly used in rifles, in which the user ejects the spent round and brings a new round up from the internal magazine by pulling back on an external knob which is called a bolt handle.

Bore — 1) The guy at the range who keeps talking and talking and talking and talking when you just want to shoot.

2) The inside surface of the barrel.

• A smooth-bore firearm is one that does not have rifling on the barrel's internal surface. Except for shotguns, these are generally antiques and collector's items.
• A big-bore firearm is one that fires a large caliber.
• A smallbore firearm is one that fires a small caliber. When used to describe a competition, "smallbore" generally means the competition will use rimfire rounds. Not all smallbore calibers are rimfire, however: .223 Remington is one example of a smallbore centerfire round.

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.

Brass — The most common material used for ammunition cases, so much so that you will often hear people refer to "picking up the brass" after shooting, even when the empty cases they are going to pick up are actually made of aluminum or steel.

Brass Magnet — We all want one. But my scientific friends tell me it's impossible. Apparently, the closest thing that's ever been found to a brass magnet is human cleavage. Wear a high-collared shirt to the range!

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 — The rearmost end of a barrel, closest the shooter (opposite from the muzzle end).

Breech Block — A mechanical piece which seals the rearmost part of the barrel (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... well, 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. It is so named because some folks hunt deer with it. Buckshot comes in different sizes. Generally speaking, the larger the pellets, the fewer of them there are in each round of ammunition.

Bullet — The solitary metal projectile that is flung downrange by the firearm. When shooters refer to the bullet, they mean only the projectile itself, not the complete package that holds the bullet before it is fired. The complete package, which includes the case, primer, powder, and bullet, is usually called a cartridge or a round.

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, but some dislike the bullpup configuration because it puts the receiver very close to the shooter's face.

Butt — On handguns, the butt is the base of the grip. On semi-automatic handguns, the magazine is inserted into a hollow magazine well located in the butt of the gun. On long guns, the butt is the rearmost portion of the stock, the part the user braces against one shoulder.

Cable Lock — A short stretch of cable with a padlock at the end. It is threaded through the action of the firearm.

Caliber — Generally speaking, caliber refers to the size of the bullet a gun will fire, and also usually refers specifically to the bullet's diameter or to the bore size of the gun that fires it. But the nominal caliber designation isn't always the actual bullet diameter or chamber measurement. Caliber numbers 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, or otherwise give more information about the cartridge.

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. For example, when shooting a semi-automatic around left-hand cover the shooter should cant the gun so the ejection port is not blocked. A slight cant may also help a cross-dominant handgun shooter improve her accuracy when shooting one-handed.

Carbine — (Pronounced "car-bean.") A short, lightweight rifle, usually with a short barrel. Carbines are often designed to shoot a pistol caliber rather than a rifle caliber.

Cartridge — The complete package that makes up a single round of ammunition. It includes the case, primer, powder, and bullet.

Case — The metal (or, very occasionally, polymer) container that holds the primer, powder, and bullet together. When empty, after the shot is fired, it may be called a spent case. Sometimes a spent case is called the brass (as in, "Let's pick up our brass before we leave the range"), because brass is the traditional and still most common case material.

Centerfire — Ammunition with the primer placed in a small cup in the bottom center of the case.

Chamber — 1) The part of the gun that holds the round while the shot is being fired. In semi-automatics, the chamber is located at the base of the barrel. Revolvers have multiple chambers, which are located in the cylinder.

2) A firearm is said to be chambered in whichever caliber it shoots. "What's that chambered in?" means, "What size ammunition does it use?"

Chapman Stance — Named for Ray Chapman, this is a modified form of the Weaver stance, so it is sometimes called a modified Weaver. The strong side elbow is held straight and locked out, while the weak hand pulls back against the strong hand thus producing the push-pull tension typical of the Weaver stance.

Choke — 1) A constricting tube at the end of a shotgun barrel, which changes the pattern of how the shot spreads out. Chokes come in different configurations to give varying effects.

2) A misfeed or failure to fire. ("My gun just choked.")

3) To mess up under stress, especially the stress of competition. ("Well, I was worried about shooting against Julie Golob, and I just choked.")

Clay Pigeon — A frisbee-shaped chunk of pottery, typically flung into the air to function as a shotgun target.

Clearing — 1) Unloading a gun and double checking that it is unloaded.

2) A trendy, "tactical" term meaning to safely enter a room while making sure there are no criminals lurking there.

3) Fixing a malfunction so that the gun is ready to fire again.

Clip — A literal clip that holds ammo cartridges, but does not feed them into the gun. It does not have a spring and is not usually encased. Handguns, with a very few limited exceptions, do not have clips; they have magazines. Using the word clip instead of magazine is one of the things that marks a new or uninformed shooter, and often drives experienced shooters right up the wall.

Cock — On hammer-fired guns, to retract the hammer so it is in position to fall forward onto the firing pin, which will in turn strike the primer and fire the shot. If the firearm has an external hammer, the gun may be cocked manually, by pulling the hammer back with the thumb (thumb cocking). Some external hammers, and all internal hammers, may be cocked simply by pulling the trigger (trigger cocking).

Collapsible Stock — A long gun term which refers to a stock that can be shoved into itself to shorten it, either for storage or to make the gun fit shooters of different sizes.

Concealed — Hidden from view. A handgun is concealed when it is carried in such a manner that an observer cannot tell for sure that it is there.

Concealment — Anything that blocks the attacker's view of the intended victim, but that won't necessarily stop a bullet.

Controlled Pair — Two shots fired in rapid succession. It is distinguished 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.

Cosmoline — An icky, sticky substance in which most of the world's old military firearms were bathed and stored upon retirement, in order to prevent corrosion. Collectors of antique military firearms spend a lot of time swapping recipes for getting the stuff out of the nooks and crannies of their beloved old guns.

Cover — Anything an intended victim hides behind that will probably stop a bullet. Cover is nearly always also concealment, but concealment isn't necessarily cover.

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.

Creep — 1) A guy at the range or anywhere else who gives you the willies. Always listen to your instincts and avoid being alone with a creep.

2) A trigger is said to creep when it does not have a consistent, clean break. Once the trigger reaches its break point, it should not be possible to move it farther to the rear, even slightly or slowly.

Crisp — A trigger is crisp when it breaks in a sudden and definite manner, with no extra movement.

Cross-dominant — Sounds a little hinky, but don't worry. It just 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 — The part of a revolver that revolves. The cylinder contains 5, 6, or more chambers that each hold a single round of ammunition.

Decocker — On double-action semi-automatic firearms, a lever that mechanically lowers the hammer without firing the gun. Like all mechanical safeties, it can fail. The decocker should never be pressed unless the gun is pointed in an absolutely safe direction.

Deringer or derringer — A small, double-barreled handgun that can fire a single shot from each barrel before it needs to be reloaded. It is loaded by folding the barrels downward and away from the receiver, a process called breaking the action open. The spent cases are then removed, and one fresh round is placed in the base of each barrel before the barrels are snapped shut again. 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.

Double Action (DA) — Originally used only for revolvers but now common in semi-autos as well, double action originally meant that the user had two choices for how to cock the hammer. The user could either cock the hammer by pulling it back with her thumb (thumb cocking), or by an extended, heavy trigger pull (trigger cocking). This reason for the use of the term has been widely forgotten. Now it generally means using the single motion of the trigger to both cock the hammer and to fire the shot. Double action firearms tend to have long, heavy trigger pulls and people who do not have strong hands frequently find them difficult to shoot well.

Double Action / Single Action (DA/SA) — DA/SA firearms are designed to operate in double action on the initial shot, and in single action on the second and subsequent shots. Consequently, these guns tend to have a long, heavy trigger pull for the first shot, and a relatively short and light trigger pull for subsequent shots. This is because the first trigger pull gets the internal parts into position, while the energy from the first shot is used to prep the mechanism for follow-up shots.

Double Action Only (DAO) — Some pistols and revolvers can only be trigger cocked and are impossible to thumb cock. Even though it drives traditionalists nuts (the apparent redundancy irritates some), these are commonly called double-action-only firearms.

Double Barrel — A shotgun with two barrels is called a double-barreled shotgun. The barrels may be situated next to each other (side by side), or vertically aligned (over/under). Double-barreled shotguns typically hold only two rounds at a time, and are designed to break open at the base of the barrel (the breech) for reloading.

Double Tap — Two shots fired in rapid succession. Generally the second shot will be fired more quickly than a new sight picture can be established. If the second shot is fired after a second sight picture is established, a double tap may instead be called a controlled pair.

Doublefeed — A malfunction in which the spent case fails to eject from a semi-automatic firearm, so when the fresh round is brought forward it cannot fit into the chamber because the other case is still in the way. It is cleared by stripping the magazine from the gun, racking the slide several times to eject the spent case, and then reloading.

Drams — A black powder weight measure. Although shotgun ammunition uses smokeless powder, in order to standardize measurements, shotgun ammunition manufacturers use dram equivalents to indicate how much power the load has. The quantity of smokeless powder in the load is compared to the amount of black powder it would require to produce the same velocity with the same projectile(s).

Dremel — A tool used by home handypersons and do-it-yourselfers to damage and destroy firearms. Never let anyone with a Dremel tool anywhere near your firearm.

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, a redundant law because there really aren't any modern firearms which aren't drop safe.

Dry Fire or Dryfire — Practicing gun manipulations, including sight alignment and trigger press, with an empty firearm. Dry fire can be very beneficial, but it is also very dangerous.

Dud — A round of ammunition that does not fire when expected.

Dum Dum — A somewhat obsolete term that refers to one of several different shapes of expanding bullets, especially when used by a soldier on the field of war. Most commonly, this term refers to a jacketed bullet illicitly or illegally modified by the user in order to create greater injury. Except in rare cases, the term does not refer to legally-produced hollowpoint ammunition. Legally-produced hollowpoint ammunition is commonly used in self defense and law enforcement applications because its reduced penetration capabilities make it safer for bystanders.

Dummy Round — An inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions. Some folks also use them in dry fire practice.

Ear plugs — A type of hearing protection that fits inside the ear canal.

Earmuffs — A type of hearing protection that completely covers both ears and is usually attached to a headband (sometimes to a neckband rather than a headband).

Ears — Casual slang for hearing protection (muffs or plugs). The human ear is very vulnerable to the sharp, loud noise of gunfire. Smart shooters always protect their ears by wearing good ear protection on the range.

Ejection Port — The opening through which the empty, spent ammunition case is cast out of a firearm.

Ejection Rod — A sliding metal dowel located at the muzzle end of a revolver cylinder. The rear end of the ejection rod holds the star, which contacts the case rims when the gun is loaded. After firing, the shooter opens the cylinder and depresses the front end of the ejection rod, causing the star to shove the empty cases out of the cylinder.

Ejector — 1) The part of a semi-auto firearm responsible for tossing the empty case out of the ejection port.

2) In most double action revolvers, empty cases are removed by the user pushing down on the ejector rod (sometimes called the ejection rod). The bottom end of the ejector rod holds the star, which shoves the spent cases out of the chambers by pushing against their rims.

Electronic Hearing Protection — A type of hearing protection that includes internal electronics to amplify human voices while excluding all noises louder than a given decibel rating. Electronic muffs are a godsend to the serious firearms student, because they allow her to safely hear instruction over the sound of gunfire on the range. They also dramatically improve range safety, especially for instructors and range officers who must be able to hear what others are doing around them while they are working.

External Safety — A safety lever found on the outer surfaces of the firearm and accessible to the user. Not all external safeties require user attention. For instance, a grip safety is an external safety, but requires no deliberate action by the shooter in order to do its job.

Extractor — The part of a semi-automatic firearm responsible for grabbing the empty case by its rim and yanking it out of the chamber as the slide travels rearward.

Failure to Extract — A semi-automatic firearm malfunction in which the extractor fails to yank the old case out of the way as the slide travels back, so the spent case is still in the chamber as the slide on its return journey tries to stuff the new round into the same space. A failure to extract often causes a doublefeed 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. Failures-to-feed and misfeeds are closely-related malfunctions, and the two problems often share a root cause.

Failure to Fire — Any malfunction that results in nothing happening when the trigger is pulled. Most commonly caused by a failure to feed the ammunition properly into the chamber, a failure to fire can also be caused by bad ammunition or by a broken firing pin.

Firearm — A mechanism that throws metallic projectiles using the energy produced through the rapid, confined burning of a propellant. Pellet guns, BB guns, airsoft guns, paintball markers, and air rifles are not firearms, because their projectiles are propelled by air pressure or a spring rather than by burned propellant.

Firing Pin — Part of the firing mechanism that serves to transfer energy from a spring-loaded hammer to the primer. The firing pin is a lightweight, very hard steel rod with a small, rounded end at its front for striking the primer. Not all firearms are actuated by hammer-struck firing pins. Some firing pins are actually part of the hammer. Others, called strikers, consist of a single piece which is directly connected to the spring that powers it.

Firing Pin Block — A type of internal safety that prevents the firing pin from moving forward for any reason unless the trigger is pulled.

Flash Reducer, Flash Suppressor, Flash Hider — A mechanical device that directs the burning gases away from the front sight, making the firearm more pleasant to shoot, especially in low light. 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 — Yanking the gun downwards just before the shot fires, causing the shot to go wild. A flinch is commonly caused by learning to shoot with a more powerful gun than the shooter is yet ready to handle. Many shooters have recurring problems with flinching throughout their shooting lives.

FMJ — See full metal jacket.

Folding Stock — Long gun term. A stock that features a hinged point so it 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.

Fore-end — The fore-end (sometimes spelled forend) is the front part of the long gun's furniture. 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. Pump-action firearms have movable fore-ends, while other types of firearms have stationary ones.

Fouling — The gritty, grubby, icky stuff that has to swabbed out of the barrel and scrubbed out of every nook and cranny of the firearm in order to clean it.

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.

Frame — The skeleton of the gun, to which all moving parts are attached.

Front Sight — See sight, front.

Front Strap — The surface of the forward part of the handgun grip.

Full Metal Jacket (FMJ) — Ammunition in which the front (visible) part of the lead bullet is covered by a thin layer of copper or another metal. This reduces fouling and makes the firearm easier to clean at the end of the shooting day, and also reduces the amount of lead dust present in the air on the range. The term is distinct from total metal jacket because in ammunition with a total metal jacket, the entire bullet is encased by another metal.

Furniture — A long gun term that basically means the pretty parts of the gun: the stock, the grip if there is one, and the fore-end. It does not include the receiver or the barrel.

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

Gas Operated — In this case, gas does not mean gasoline. It means the superheated air and other stuff created by burning powder. A gas-operated firearm is one that uses the energy from these superheated gases to work the action.

Gauge — The shotgun equivalent of caliber. Sort of. Rather than being a direct measurement of bore size, gauge indicates how many lead balls the same diameter as the gun's barrel would equal one pound. For this reason, a 20-gauge barrel is actually smaller in diameter than a 12-gauge barrel.

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 weight measurement used for bullets. The more grains, the heavier the bullet. Powder is also measured by grains, but this is generally of interest only to reloaders. There are 7000 grains to a pound.

Green Ammunition — Ammunition that contains no lead in any component.

Grip — 1) The part of the handgun that the shooter's hand wraps around. In a semi-automatic pistol, the grip contains the magazine inside the magazine well. The grip's muzzleward surface is called the front strap, while its rearward surface is called the backstrap. Its base is called the butt. See pistol grip.

2) 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 is disengaged by obtaining a firing grip on the handgun. Most 1911-pattern pistols feature a grip safety.

Group — A gathering of holes in the target. Group size is usually measured center-to-center from the holes which are farthest apart. The smaller the group, the happier the shooter.

Gunpowder —

Hair trigger — A trigger that breaks from an extremely light touch. Trigger pull weight is measured by the number of pounds and ounces of pressure required to pull the trigger past the break. A hair trigger is a trigger that could be pulled past the break by the weight of a single strand of human hair. Obviously a descriptive term that is never strictly accurate, it is sometimes used in news stories to denote a trigger that can easily be pulled by a normal human being instead of by someone with the hand strength of an upland gorilla.

Hammer — 1) A tool used by a do it yourself home gunsmith to destroy firearms.

2) On guns so equipped, the hammer is the part that rotates to provide the percussive impact on the primer, or that strikes the flint to the frizzen on antique firearms. 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.

3) To hit the target repeatedly.

Handgun — A small firearm designed to be fired while held in one or both hands, rather than while braced against the shoulder.

Hardball — Slang for a full metal jacket bullet with a round nose. In casual conversation, the term is most commonly used in referring to .45 ACP caliber ammunition, but may be used for other calibers as well. "They all fall to hardball."

Heavy Trigger — A trigger that requires a lot of pressure to pull it past the break point. Heavy is a subjective term that depends upon the gun type. Speaking very generally, in a defensive handgun anything under around 5 pounds is light, and anything over around 8 pounds is heavy. Rifles usually have considerably lighter triggers than handguns, and even a heavy rifle trigger is often lighter than a light handgun trigger.

High Kneeling — A shooting position in which one or both knees are touching the ground, but the shooter is otherwise erect.

Hollowpoint — A bullet shape. With a deeply dimpled nose, a hollowpoint is designed to expand and spread out on impact; some hollowpoints are also designed to fragment as they expand. Hollowpoint bullets are most commonly used in law enforcement and self defense applications, because they are most likely to stop an assailant with as few shots as possible, and least likely to overpenetrate the target and harm an innocent bystander.

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.

Integral Lock — A lock that may prevent the firearm from being fired and which is built into the gun itself. Because of the risk of having a non-functional firearm when you most need it, integral locks are very controversial in the self defense firearms community.

Internal Safety — A safety which is placed within the gun itself 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 ordinary, mechanical sighting system which usually comes with the firearm. It is so called to distinguish it from laser sights, red dot sights, and scoped sights.

Isosceles Stance — The gun is held thrust straight out from of the body, with both arms straight. The arms and upper body form an isosceles triangle when seen from above. See the Stance article for more information.

Isosceles Stance, Classic — Classic Isosceles positions the feet shoulder width apart, on the same plane, and pointed toward the target. Knees can be locked or slightly flexed. The lower body thus forms a second isosceles triangle.

Isosceles Stance, Modern — Modern Isosceles positions the lower body to fight or run. The feet will be shoulder width apart, knees slightly flexed, with the strong-side foot roughly a half-step behind the weak-side foot. Shoulders will be forward of the hips, and hips forward of the knees.

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.

Jam – Revolvers — Contrary to popular misconception, revolvers can jam. They rarely have minor malfunctions. When they do, the problem is often ammunition-related and a second pull of the trigger is the usual cure. If a second pull of the trigger does not clear up the problem, a trip to the gunsmith may be needed. As most people know, such problems are extremely rare, but they can happen.

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. Keyholing sometimes, but not always, indicates a safety issue such as using the incorrect caliber for the gun.

Kick — See recoil.

Laser — As used around firearms, a laser is an alternative sighting device similar to a 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 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 itself as part of the guide rod.

Laser Grip — A type of aftermarket firearms 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.

Lead — [pronounced leed] 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 — [pronounced led] The metal from which bullets are traditionally made. They may also be made of steel, copper, or other materials.

Lead Fouling — Fouling is the icky stuff that collects in firearm barrels and other parts of the gun, and needs to be swabbed or scrubbed out when cleaning the gun. Lead fouling is fouling which is composed primarily or entirely of lead, and which requires strong solvents to remove. Its presence can be very dangerous in barrels with polygonal rifling, because it can narrow the diameter of the barrel, causing an increase in ammunition pressure to extreme levels that the firearm is not designed to contain.

Length of Pull — 1) The distance between the face of the trigger and the rearmost surface of the gun. On handguns this length is measured from trigger face to backstrap, while on long guns it is measured from trigger face to the butt of the gun. A firearm with a shorter length of pull is generally more apt to fit a small-statured shooter, or one who has small hands.

2) The distance the trigger must travel before it fires the gun.

Less-Lethal Ammunition — Ammunition which, by its design, is less likely to kill someone than traditional ammunition is. When used in unaltered firearms, this is almost exclusively a shotgun term. There are a lot of different types of less-lethal ammunition, including beanbag rounds, pepper balls, and rock salt. Although it is entirely possible to kill someone with less-lethal ammunition, such ammunition does not always stop a determined attacker. Because of this, less-lethal ammunition is generally considered a very poor choice for self defense.

Lever Action — A rifle term. Lever-action rifles have an oversized lever around the area of the trigger guard (often including the trigger guard itself). 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. This motion also typically cocks the hammer of the rifle.

Light Double Action (LDA) — A double-action semi-automatic firearm which is designed to have a much lighter pull than is usual for a double action.

Limp Wristing — Because they function on spring tension, semi-automatic pistols require a solid platform in order for the action to work correctly. Failing to provide this via a solid grip can result in misfeeds or other malfunctions. The problem is called limp-wristing because a floppy, limp wrist is the most common culprit when shooter error is responsible for such failures. However, some gunsmiths claim that any gun that malfunctions when held loosely needs mechanical adjustment.

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. They are a source of some controversy in the shooting community because many shooters believe their presence encourages the ignorant to violate the first, and most important, of the Four Rules: treat every firearm with the cautious respect you would give a loaded firearm.

Loading Gate — 1) Antique, single-action revolvers are loaded by flipping open a tiny little door that allows the user to load or unload one chamber at a time. This tiny little door is called a loading gate. Double-action revolvers do not have loading gates; rather, the entire cylinder swings down so all the rounds can be loaded at once.

2) Pump and semi-automatic shotguns, and lever-action rifles, often have a spring-loaded cover over the entry to an internal magazine. This cover is called the loading gate. The loading gate moves out of the way when a cartridge is pressed against it, allowing the magazine to be filled.

Long gun — A firearm with an extended barrel, usually designed to be fired while braced against the shoulder. The most common types of long guns are rifles and shotguns.

Long Trigger — A long trigger is one with an exceptional length of pull. It is a subjective term that very much depends upon the type of gun being discussed.

Loophole — Doing legal things that anti-gun politicians and media don't approve of.

Low Kneeling — A shooting position in which one or both knees are touching the ground and the shooter tries to get as low as possible.

Machine gun — A fully automatic firearm that rapidly fires multiple rifle-caliber shots with a single pull of the trigger.

Made — In casual range conversation, if someone admits they "got made," it means someone caught them carrying a concealed handgun. The stories about this can range from pretty funny to downright disastrous.

Mag — See Magazine, Magnum.

Magazine — An ammunition storage device, usually located within or attached to the firearm, that feeds rounds into the mechanism by use of spring tension. It is sometimes erroneously called a clip. Calling a magazine a clip drives experienced shooters crazy. Handguns, with very few and rare exceptions, don't use clips at all. They use magazines. A box magazine is the most common type of handgun magazine. Internal magazines, which do not detach from the firearm, are commonly used in rifles and shotguns. Internal magazines may be box-shaped, or they may be tubular. On military rifles, external drum-shaped magazines are common. Magazines can often be found in different types and carrying capacities even for the same make and model of firearm.

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 designed to make it easier to fill magazines using less hand strength, without hurting one's fingertips or thumbs. The author is particularly fond of the UpLula brand universal loader, but many other types are available.

Magazine Pouch — Commonly shortened to mag pouch, this is a device to hold extra magazines which fastens to the shooter's belt.

Magazine Safety — See magazine disconnect.

Magazine Well — The opening in the bottom of the gun into which a box magazine feeds. On a semi-auto handgun, the magazine well is at the base of the grip; on a rifle, it is usually placed somewhere ahead of the trigger guard.

Magnum — A designation used by ammunition companies to denote a cartridge with more power than one would traditionally expect for the bullet diameter. 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 — The mainspring provides the initial source of energy needed to fire the gun. Cocking the hammer compresses the mainspring, capturing potential energy. That energy is released when the hammer falls, striking the firing pin which in turn strikes the primer, igniting the powder. Not all firearms have mainsprings and hammers. Some are striker-fired instead.

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. All manual safeties are also external safeties, but not all external safeties are manual safeties as well.

Misfeed — In semi-automatic firearms, a failure of the next round to completely enter the chamber. A misfeed can keep the gun from going into battery, which in turn may prevent the gun from firing. Misfeeds and failures to feed are closely related: 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.

Moon Clip — A flat, circular loading device for revolvers, similar to a speedloader in that it holds the ammunition together and facilitates quick loading. Unlike a speedloader, however, a moon clip 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 gently derogatory name for any palm sized handgun which fires a small caliber.

Muffs — A type of hearing protection which completely covers both ears and is usually attached to a headband (sometimes to a neckband rather than a headband).

Mushy — Similar to creep, it denotes a trigger that has a squishy or uncertain feel, especially around the break point.

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 end of the barrel where the bullet comes out.

Muzzle Brake — A system of vents placed near the end of the firearm barrel to reduce recoil and muzzle rise.

Muzzle Control — Being aware of which direction your firearm is pointed at all times, and always keeping it pointed in a safe direction.

Muzzle Loader — A firearm design in which the ammunition and its propellant are loaded into the firearm from the front end. Sometimes called a black powder gun, after the type of propellant most commonly used. Some muzzle loaders are antiques, but there are many modern hunting firearms which are loaded in this manner.

Muzzle Rise — How much the muzzle end of the barrel lifts during the recoil process.

Negligent Discharge — An inadvertent shot which is not caused by a mechanical failure of the gun, and which involves preventable human error. Negligent discharges almost always involve violating one or all of the Four Rules, and always involve bad choices.

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 painted dabs of phosphorus. Nearly all use a standard three-dot system, with one dot for the front sight and two, spaced on either side, for the rear sight.

Off hand — 1) Shooting off-hand means to fire while standing, without bracing against a bench, bipod, tree, or any other rest.

2) The non-dominant hand.

Open Sights — The most common type of iron sights. Open sights are called open because the rear sight is an open-topped U or a V or a square-notch shape, in contrast to the closed circle commonly found in aperture sights.

Out of Battery — Most firearms do not have literal batteries. But a 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 / Under — A shotgun with two barrels that are vertically aligned with each other, one on top of the other.

Over-travel — Immediately after the trigger break which fires the shot, the trigger should be unable to move any farther to the rear. If it is able to continue moving to the rear after the shot has fired, the trigger is said to over-travel.

Owner’s Manual — A rarely-read document that contains a surprising amount of necessary information. If you've lost yours, visit the manufacturer's website to download a new one, or pick up the phone and ask the company to send you a fresh copy. At the risk of engaging in a little crazy talk: when all else fails, read the manual.

P+ Ammunition (+p and +p+) — 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 produced in that caliber, while ammunition marked +p+ produces even more power and pressure than the +p loading.

Passive Safety — Any safety, internal or external, which functions apart from the shooter's conscious control. Grip safeties are one example of a passive external safety; drop safeties are an example of a passive internal safety.

Patridge Sight — A type of sight designed by E.E. Patridge in the late 1800s, often used on handguns. It has a open-topped square rear sight and a front sight consisting of a thick blade with a flat top.

Pattern — A shotgun term which refers to the manner in which the pellets spread out as they exit the gun. It is sometimes called the spread, although strictly speaking spread refers to the actual distance measured between the two most widely-separated points of impact, while 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.

Pellet — In target shooting, a chunk of metal fired from a gun. In hunting, a chunk of poop dropped from a deer.

Pistol — Another term for handgun. Some claim it refers only to semi-automatic handguns, but this is an incorrect bit of firearms lore: many early patents refer to revolving pistols.

Pistol Grip — A long gun term with two possible meanings.

1) Some long guns feature a standard stock (one which can be braced against the shoulder) that has an extra handle behind the trigger for the firing hand to wrap around. The extra handle is called a pistol grip. When used properly by an experienced shooter, a standard stock equipped with such a pistol grip can improve the controllability of the gun, although firing it can be uncomfortable for the wrist.

2) A super-short, pistol-shaped stock which completely replaces a standard long gun stock and makes the long gun impossible to fire from the shoulder. A gun so equipped is most easily fired from the hip without sighting. This looks cool, but is often extremely painful to fire and is no aid to accuracy.

Plinking — Recreational shooting, or shooting for fun rather than for scored competition or defense practice: "I just spent an afternoon plinking with the kids." Plinking often involves a brick of .22LR ammunition and some reactive targets.

Point Shooting — Shooting without using the sights. Instead of using sights, point shooters use body position or other cues to provide a rough index of where the shots will land.

Port — An opening. The ejection port is the opening in the side of a semi-auto from which spent cases are ejected.

Porting — Openings 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 the trade off is that the gun becomes much louder when fired and produces a brighter flash. Porting is quite safe on the range, but is not generally recommended for defense handguns, because when used for defense, the gun may need to be fired from an odd position while it is still very close to the defender's body or face. When a ported gun is fired from such positions, escaping gases may cause serious burns or permanently blind the shooter.

Powder — The chemical propellant which is burned to produce the hot gases which send the bullet flying downrange. Sometimes called gunpowder, although experienced shooters usually reserve the term gunpowder to mean black powder rather than modern smokeless powder.

Pre-travel — Some triggers can be pulled slightly backwards before the shooter can feel any tension and before the hammer or striker begins to retract. Thus, pre-travel is any movement of the trigger that begins before the trigger starts doing its real work.

Primer — That portion of the ammunition which contains a tiny quantity of explosive compound that detonates when struck with force, igniting the powder. Hot gases from the burning powder then send the bullet downrange. In centerfire ammunition, the priming compound is located inside a tiny metal cup which can be seen by looking at the underside of the case. In rimfire ammunition, the priming compound is distributed evenly around the inside of the bottom rim of the case.

Printing — A condition in which the outline of the concealed handgun may be discerned through the outer clothing. The firearm itself is not visible, but its presence and shape may be apparent to an observer.

Propellant — The chemical whose rapid burning sends the bullet on its way, usually called powder or gunpowder. Modern gunpowder is sometimes called smokeless powder or simply powder, terms which distinguish it from the original black powder.

Pull — 1) 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 for her to shoot.

Pull Distance — The distance the trigger must travel before it reaches the break point and fires the gun.

Pull Weight —

Pump Action — A long gun term. Common in shotguns, less common in rifles. Pump-Action guns have a moveable fore-end. After the shot fires, the user pulls sharply back on the fore-end to eject the spent shell or case, and then shoves the fore-end forward again to bring a fresh round into the chamber.

Racking the Slide — A semi-automatic handgun term which means pulling the slide back to its rearmost position, and then letting it go forward under its own spring tension. If the magazine is loaded and inserted in the gun, racking the slide loads the chamber and prepares the gun to fire.

Rail — A feature on the underside of the frame below the barrel on many handguns which allows various aftermarket accessories to be attached the firearm. It is most commonly used to attach specially-designed flashlights or laser sights.

Rails — The usually metal surfaces upon which a semi-automatic's slide travels to and fro as each shot is fired. For proper function, they need to be clean and wear a light coating of oil.

Reach — The measurement from the backstrap to the face of the trigger. The shorter the reach, the smaller the hands that will easily be able to fire the gun.

Reactive Targets — Targets that do something when you hit them, such as fall over, burst, send up smoke, or make a noise. Examples of reactive targets include bowling pins, full or empty soda cans, rotten fruit, steel gongs, and balloons. Responsible shooters always clean up any mess left behind by their reactive targets.

Rear Sight — See sight, rear.

Receiver — The essential part of the gun, containing the firing mechanism and action. In semi-automatic handguns and revolvers, this part is typically called the frame.

Recoil — Sometimes called kick, recoil is the rearward force produced by a gun when it is fired. A shooter is said to be recoil sensitive if she does not enjoy the sensation caused by this rearward force. It is possible to scientifically measure the exact amount of recoil produced by a particular gun and ammunition. However, perceived recoil – the amount of force and the type of sensation it produces as felt by the shooter – may differ substantially from actual recoil as measured by the mathematician or scientist. Perceived recoil may be influenced by the gun's internal architecture, by design details, by the spring weight, by the type and size of ammunition chosen, and by how well the firearm fits the shooter. The interplay between these complex variables can be difficult to assess simply by holding or examining the gun without firing it.

Recoil Spring — The 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.

Red Dot Sight — A sighting system which replaces the front and rear (iron) sights with a see-through screen upon which a colored dot may be superimposed over the target. It is typically most useful for competition work rather than on guns intended to be used in self defense, though newer designs are beginning to change that.

Reload — 1) To refill the firearm with ammunition in order to continue shooting.

2) A form of recycling wherein a shooter reuses empty brass cases and fills them with new primers, powder, and bullets. The old cases must be cleaned, resized, and have the spent primers removed. After the cases are prepared, a new primer is inserted into the primer pocket, a carefully-measured amount of powder is placed in each case, and a new bullet is seated to a precisely-measured depth within each case. Most of these steps are accomplished on a specialized piece of equipment called a reloading press.

Reset — The point of the trigger's return journey at which the gun's internal mechanisms are ready to fire another round. On many guns, after the shot has fired, if you hold the trigger to the rear and then slowly release it, you can feel or sometimes hear an audible click as the trigger reaches the reset point. The reset point varies greatly from one type of gun to another, and some guns do not reset until the trigger has been allowed to complete its entire return journey.

Reticle — The object seen in the center of a firearm scope that assists the rifleman in aligning the shot. The most familiar reticle shape is a simple cross, which is commonly called the crosshairs. Other possible reticle shapes include circles, chevrons, and dots.

Revolver — A type of handgun with one barrel and a rotating cylinder which contains multiple chambers. As the cylinder is rotated, either by cocking the hammer or by pulling the trigger, the chamber containing the spent cartridge is rotated away. This brings a fresh cartridge into alignment with the barrel, ready to fire when the hammer falls. A revolver cylinder typically holds 5 or 6 rounds of ammunition, though it may hold considerably more depending upon the caliber.

Riding the Slide — Racking 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.

Rifle — A firearm designed to be fired while braced against the shoulder, and which uses a spiral groove cut along the inside of the barrel to spin the bullet. Spinning improves the projectile's accuracy and range, the same basic principle which makes a football travel in a straight line rather than wobbling when it is thrown correctly.

Rifling — Continuous spiral (helical) grooves cut along the inside surface of a firearm barrel to improve the accuracy and range of the bullet, and stabilize the bullet's flight, by giving it a spin as it leaves the barrel. Rifles, by definition, always have rifling; handguns typically do; and shotguns rarely do. Because shotguns typically do not have rifling in the barrel, some shotgun slugs (very large bullets) feature rifling on their outer surfaces. These are called rifled slugs.

Rimfire — Ammunition in which the primer is located in the outer edge, or rim, at the bottom of the case. Typically, rimfire rounds are smaller in diameter than centerfire rounds. Although there are several other rimfire cartridges, the term "rimfire" is often used in casual conversation to refer exclusively to the .22 Long Rifle round. Rimfire ammunition tends to be less reliable than centerfire ammunition. For this reason, it is a poor choice for self defense unless no other alternatives are reasonably available.

Rough Trigger — A trigger which has a gritty or inconsistent feel during the pull.

Round — 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.

Round Gun — Slang term for a revolver.

Round Nose — The classic bullet shape.

Running the Gun — Performing all necessary manipulations (such as loading, unloading, or clearing jams) to keep the firearm functioning as designed.

Safe — 1) A firearm is said to be on safe when its safety is engaged and off safe when it is ready to fire. Wise shooters place only guarded trust in mechanical safeties, and always follow the Four Rules even when the safety is engaged.

2) A locking container in which firearms should be stored when they are not in use. True safes are rated by the Underwriters' Laboratories as such. Other types of locking storage commonly called safes include "Residential Security Containers" (RSCs) and security lockers.

Safety — 1) A mechanical component of a firearm designed to reduce the chance of an unintentional discharge.

2) Conscientiously following the Four Rules every single time you handle a firearm... even if you think the gun is unloaded, and even when you think no one's looking.

Scattergun — A casual term for a shotgun, so called because the shot spreads out or scatters after it exits the shotgun's muzzle.

Scope — A magnifying tube through which the shooter may see the target and thus 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.

Sear — The part of the trigger mechanism which holds the hammer or striker back until the correct amount of pressure has been applied to the trigger, at which point the hammer or striker is released to discharge the firearm. The sear may be a separate part, or may be a surface incorporated into the trigger.

Semi-automatic — A firearm which uses the energy from the fired shot to eject the empty case and feed the next round into the chamber. Sometimes called an autoloader, a bottom-feeder, or (inaccurately) an automatic.

Semi-Wadcutter — A modified wadcutter bullet with slightly sloping edges, designed to load smoothly in a semi-automatic pistol.

Shell — An empty ammunition case. Sometimes called the brass, even when it is composed of another material such as aluminum or (rarely) polymer.

Shell, Shotgun — Shotgun ammunition often comes encased in plastic shells rather than in metal cases, so shotgunners often refer to shells in conversations where a rifleman or handgunner would refer to cases, cartridges, or rounds. A shotgun shell usually contains a primer, powder, shot, and a wad. In place of the shot (multiple pellets), the shell might instead hold a single large bullet called a slug.

Shooting Sports — There are a lot of different competitions and other games which involve firearms. These are all referred to collectively as the shooting sports.

Short Trigger — A 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-stroking — On a pump-action firearm, short-stroking means 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. If the shooter doesn't pull the fore-end all the way back, the old case or shell fails to eject and the gun often misfeeds. If the shooter doesn't shove the fore-end all the way forward, 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).

Shot — In shotgunning, multiple pellets contained in the shell and sent downrange when the shotgun is fired. No matter how many pellets there are, shot in this sense is pluralized without adding an "s" to the end: "a handful of shot."

Shotgun — A firearm typically used to fire a number of small spherical pellets collectively called shot. Shotguns usually have a smooth, unrifled bore, but may be fitted with a rifled bore designed for firing a single slug rather than a collection of shot. Sometimes called scatterguns because the shot spreads out in a conical pattern upon leaving the gun.

Shoulder — To bring the butt of a long gun's stock to the shooter's shoulder, preparatory to firing the gun.

Side-by-Side — A shotgun with two barrels which are situated next to each other.

Sight — A mechanical, optical, or electronic device used to aim a firearm. The most common type of sights, generally referred to as 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 Alignment — The 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 Picture — What the shooter sees when looking through the sights at the target.

Sight, Front — 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.

Sight, Rear — The 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 vee, a ring, or simply two dots designed to be visually placed on either side of the front sight while shooting.

Silencer — See suppressor, sound.

Single Action (SA) — A single-action firearm is one in which pulling the trigger does only one thing: fires the shot. The trigger is not used to cock the hammer, rotate the cylinder, or retract the firing pin.

• Revolvers — A single-action revolver requires the user to manually pull the hammer back ("cock the hammer") before each and every shot. Pulling back on the hammer causes the cylinder to revolve, and brings a fresh round into alignment with the barrel ready to be fired.
• Semi-autos — 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.

Slack — To 'take up the slack' means to pull the trigger through its pre-travel stage.

Slide — On a semi-automatic firearm, the slide is the part of the gun that moves quickly back and forth with every fired shot, ejecting the spent case as it moves to the rear and loading a fresh cartridge into the chamber as it moves forward again. On a handgun, it is often the uppermost portion of the gun and the sights are usually fastened to its top. 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 Lock — When most semi-automatic firearms have been fired until empty, the slide will remain in its rearmost position rather than going forward as if to chamber another round. This condition of the gun is called slide lock. Shooting to slide lock means shooting until there is no more ammunition in your semi-automatic gun, because the slide usually locks back with the chamber empty after firing the last round.

Slide Release — The slide release lever, usually located on the left side of the slide, is pushed down to unlock the slide and allow the slide to move forward into its normal position. It is sometimes called the slide stop or slide stop lever.

Slide Stop — The slide release lever.

Sling — A long strip of leather, plastic, or nylon which is fastened at the fore and rear of the gun. A sling enables easy carry of long guns. It also allows the shooter to wrap body parts into it and brace solidly against the tension thus produced for a steadier hold.

Slug — A single, very large projectile fired by a shotgun. It may be plain, or it may have spiral grooves, called rifling, cut into its outer surface to help stabilize it during flight.

Slug Gun — Slang 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). Slug guns are most commonly used for deer hunting in states which prohibit hunting deer with rifles.

Smokeless Powder — Modern gunpowder, so called because it doesn't produce the thick clouds of acrid black smoke that black powder does.

Snap Cap — An 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.

Snubby — Casual slang for a short-barreled revolver.

Snubnose — Casual slang for a short-barreled revolver.

Speed Strip — A flat piece of rubber which holds revolver cartridges preparatory to loading them into the revolver's cylinder. It is designed to lie flat in the pocket, so it is a boon to concealed carry folks who want to carry extra ammunition discreetly. Using a speed strip to load a revolver is slightly faster than rummaging around in your pockets for loose ammunition before stuffing rounds into the cylinder one by one. But only slightly.

Speedloader — A circular gadget which holds revolver cartridges preparatory to loading them into the revolver's cylinder. It holds the rounds in the correct configuration to plunk all of them at once straight into the chambers.

Spread — See pattern.

Springs — Most guns have springs. Big springs, little springs, tiny springs that bounce across the room and hide under the couch while you hunt for them in vain. Not that we're bitter about that.

Squib — A round of ammunition which has far less power than it is supposed to, often having no powder at all. Squib loads can result in a bullet getting lodged in the barrel, which can be dangerous if the gun is fired again before clearing the obstruction out of the way. Squib loads are very uncommon when shooting commercial ammunition.

Stacking — A noticeable increase in pull weight as the trigger travels. Ideally, the trigger pull should feel as if it remains the same weight throughout its entire journey.

Stance — How the shooter positions her body while shooting. The three most widely-known handgun stances are Weaver, Chapman, and Isosceles.

Stock — 1) The back part of a rifle or shotgun, excluding the receiver. It is commonly made of wood, wood laminate, metal, or synthetic materials.

2) In competition, an unaltered firearm, used in the same configuration in which it came from the factory.

3) Some people and companies refer to handgun grip panels as stocks.

Stovepipe — Failure of a spent case to completely eject from a semi-automatic firearm. This malfunction is called a stovepipe because the case usually stands on end while lodged in the ejection port, thus resembling a stovepipe sticking up out of a roof.

Striker — On guns so equipped, the striker is the device that moves linearly to provide the percussive impact on the primer. Not all firearms have strikers; many have firing pins which are struck by a hammer instead.

Striker Fired — A striker is a form of firing pin that replaces the hammer and firing pin with a single unit. So a striker-fired handgun is a semi-automatic which uses a striker, rather than a hammer or a firing pin, to hit the primer and fire the round.

Stripper Clip — Stripper clips are simple clips made of metal or sometimes plastic that holds several rounds of ammuntition in a row. It is used to quickly fill a magazine. The ammo is pushed out of the clip and into the magazine in a fluid motion. Unlike an ammo clip, the stripper clip does not stay in the magazine and it is not part of the firearm's function. It is merely an optional speed loading device.

Submachine Gun — A fully automatic firearm which fires a pistol caliber.

Suppressor, Flash — See flash reducer.

Suppressor, Sound — A device that fits on the muzzle end of a firearm to reduce (but not eliminate) the loud noise created when the gun is fired. Suppressors cannot reduce the loud crack caused by the bullet as it exceeds the speed of sound, but can reduce the noise caused by the escape of gases from the end of the barrel. Like fully-automatic firearms, sound suppressors have been strictly regulated in the United States since 1934. Purchase requires a $200 federal authorization stamp, a background check, the approval of local law enforcement, and nearly the same paperwork required to purchase a fully automatic weapon. Although strictly regulated in the US, many European laws require shooters to use sound suppressors, because the sound of gunfire can cause permanent hearing damage and is often considered a nuisance by neighbors who live within earshot of a range.

Tang — The 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, Bang — The 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, the final step in the complete sequence which gives this procedure its name.

Thumb Safety — An external, manual safety which is typically disengaged with the firing-hand thumb.

Total Metal Jacket — A type of ammunition in which the lead bullet is entirely encased inside another metal, usually copper. This reduces fouling and makes the firearm easier to clean at the end of the shooting day, and also reduces the amount of lead dust present in the air on the range. Ammunition with a total metal jacket is distinct from ammunition with a full metal jacket because full metal jacket simply means the nose of the lead bullet is covered with another metal, while total metal jacket means the entire lead bullet is encased in another metal.

Trigger — The bang switch. Pulling the trigger sets in motion the whole chain of mechanical events which results in a bullet coming out of the muzzle end of the gun. 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 Control — Never putting your finger on the trigger until your sights are on target, then pulling the trigger smoothly, without jerking or yanking, and following through by realigning the sights before allowing your finger to come off the trigger. Every time. Even when you're in a hurry.

Trigger Group — The 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 Guard — The hoop encircling the area around the trigger. 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 Jerk — No, not the guy in the lane next to you – well, probably not, anyway. Jerking the trigger means yanking it back abruptly, thus pulling the muzzle of the gun downward at the moment the shot fires. This does not help accuracy.

Trigger Lock — A walnut-sized lock that fits into the trigger guard area and is designed to prevent the trigger from moving. Its chief disadvantage is that, ignoring or defying the cautionary warning labels, too many users install these on loaded firearms. Most experienced shooters believe that unnecessarily fiddling around in the trigger guard area creates many mishaps.

Trigger Pull — The entire process of moving the trigger from its forwardmost position to its rearwardmost position, causing the hammer to fall and the shot to fire.

Trigger Pull Weight — How much pressure the trigger finger must put on the trigger before the gun will fire. Trigger pull weight is measured in pounds and ounces.

Trigger Safety — An 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 Scale — A specialized type of hanging scale designed to test trigger pull weight.

Trigger Slap — 1) Flapping your finger onto the trigger and yanking it to the rear, usually accompanied by flopping your finger immediately back off the trigger at the moment the shot fires. Trigger slap is generally a bad thing, because unless the firearm has an incredibly short, light trigger (such as those used in high end competition), it almost inevitably misaligns the sights and sends the shot wild.

2) An uncomfortable sensation caused by the trigger springing back into the shooter's trigger finger while firing.

Trigger Stop — A mechanism for adjusting overtravel.

Trigger Weight — See trigger pull weight.

Wad — 1) In shotgunning, a clump of something, commonly cardboard or plastic, which acts as a buffer between the shot and the powder in shotgun ammunition. It seals in the gases which propel the shot out of the barrel. Without a wad, the gases would go whistling past the shot instead of propelling it out the barrel.

2) 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 — A cylinder-shaped bullet with sharp front edges, typically used in revolvers. When used on a paper target, it creates a very tidy hole with crisp, easily-measured edges, and is thus often used in target competitions.

Weapon — A tool designed for a human being to enable her to defend herself and her community, or to commit aggression against other people, or (sometimes) to take game animals. By definition, firearms used for concealed carry are weapons both by design and intent. And all firearms are defined as weapons under the law.

Weaver Stance — A shooting position named after Jack Weaver, who was a Deputy Sheriff in the 1950s when he first began using this stance in competition. In the Weaver stance, the body is bladed 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. See the Stance article for more information.

Wheel Gun — Casual slang for a revolver.

Youth Rifle — A 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 Stock — A short stock, often ideally sized for teenagers, average-sized adult women, and small-statured adult males.

Zero — A 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. Because of the effects of gravity and inertia on the bullet as it travels, there is no such thing as a gun with sights that are accurate at all distances. Sights need to be "re-zeroed" to compensate for different distances, or the shooter must adjust her point of aim (aligning the sights a bit higher on the target, for instance). If the gun's sights are adjusted for shooting at 200 yards, the gun is said to have a 200-yard zero.