A Glossary of Gun Terms

Navigating the world of firearms ownership is tough. It’s made even harder by the fact that there are so many words used in the gun industry that mean specific things. All these gun terms can get very confusing. To help you out, we’ve created a list of common words and phrases used by people who own guns. Feel free to refer back to this list when the language of guns ties you up in a knot.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

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A

ACCURIZE: Improving the accuracy of a firearm by reducing the tolerances between parts.

ACP: Short for Automatic Colt Pistol cartridge.

ACTION: The mechanism of a firearm, usually located within the receiver.

AK: Avtomat Kalashnikov, usually associated with the AK-47 Russian service rifle.

ANVIL: A part of a cartridge primer used to ignite the priming compound after it has been crushed by the firing pin.

AP: (a) Armor Piercing. (b) Automatic Pistol.

APERTURE SIGHT: A front or rear sight with a circular opening in the center. Also known as a Ghost Ring Sight or Peep Sight.

API: (a) Armor Piercing Incendiary ammunition. (b) The American Pistol Institute, the original name for Gunsite.

AR: Automatic Rifle. Also, Armalite Rifle, as in AR-7 or AR-15.

AR-15: Commercial semi-automatic version of the selective fire Colt M-16 U.S. service rifle.

AUTOLOADING: A firearm that uses the force of the explosion of each shot to unlock the mechanism, extract and eject the empty cartridge case, and reload by stripping and feeding another cartridge from the magazine into the chamber. The trigger must be pressed for each successive shot. See Semi-Automatic.

AUTOMATIC: Firearms that use the force of the explosion of the first shot to continuously unlock, extract, eject, reload, lock, and fire. This type of gun will operate continuously as long as there is ammunition in the belt or magazine and the pressure on the trigger is continued. This term is often used, incorrectly, to describe autoloading or semi-automatic firearms. 

B

BACKSTRAP: The rear extension of a pistol or revolver frame that curves downward.

BACKSTOP: A mound of earth, hill, or any other barrier that will safely deflect, stop, or absorb bullets.

BALLISTICS: The science of studying moving projectiles. Ballistics is further broken down into three areas of study: internal, external, and terminal.

BALLISTIC COEFFICIENT: A calculated number derived from how a bullet’s shape, length, weight, diameter. and nose design affect its stability, velocity and range versus air resistance.

BARREL: A metal tube containing the bore through which a projectile or charge passes upon firing.

BARREL BAND: A strip of metal that holds the barrel and forearm together, holding the barrel in the forearm groove.

BASE: The rear end of a projectile, bullet, or cartridge.

BEAD: A small knob of contrasting metal, usually brass or gold, that is placed near the muzzle end of the barrel used as a front sight in aiming.

BINOCULAR VISION: Sighting with both eyes open.

BIRD: A clay target used in skeet and trap shooting.

BLACK POWDER: The original gunpowder and a forerunner of smokeless powder, created from a mixture of charcoal saltpeter and sulfur.

BLOWBACK: A method of weapon operation where the force of expanding gases moving rearward provides the energy required to initiate and complete the cycle of operation of the firearm.

BLUING: A chemical process that creates a controlled oxidation of a metal surface that results in a blue or blue-black finish.

BOAT TAIL: The tapered rear end of a bullet that is designed to increase ballistic efficiency at long range.

BOLT: A sliding mechanism that does the feed in some types of firearms. It usually contains the extractor and firing pin and supports the base of the cartridge case.

BOLT ACTION: A rifle and shotgun mechanism whereby the breech is opened and closed by a manually operated bolt. 

BORE: (a) The interior of the barrel through which the charge of the bullet passes. (b) The inside diameter of the barrel, measured from land to land.

BOX MAGAZINE: A box shaped metal container for holding cartridges.

BRASS: An empty metallic cartridge case.

BREATH CONTROL: Properly controlling your breathing during the aiming and firing process in order to minimize disturbance of sight alignment and sight picture.

BREECH: The rear end of the barrel into which a cartridge is inserted.

BUCKSHOT Large size lead shot for use in shotgun shells commercially manufactured in seven sizes with the following designations and diameters:

• #000 (.36″)
• #00 (.33″)
• #0 ( .32″)
• #1 (.30″)
• #2 (.27′”)
• # 3 (.25″)
• #4 (.24″)

BUFFER: A part of the firing mechanism that absorbs recoil.

BULLET: A small arms projectile normally fired from a rifled barrel.

BULLET BASE: The rearmost end of the bullet.

BULLET DROP: The vertical drop of a bullet due to gravity.

BULL’S EYE The center of a target. Also a shot that hits it, hence, any successful hit.

BUTT: The shoulder end of a gunstock or the bottom of a revolver / pistol frame.

BUTT PLATE: A metal, plastic, or rubber covering for the butt of a gunstock.

C

CALIBER: The bore diameter of a rifle or handgun, measured from one land to the opposite land of the rifling, usually designated in fractions of an inch or millimeters, although a stated caliber may not be an exact figure. 

CANNELURE The groove around the circumference of a bullet or case.

CANT: The tilt of a barrel to the right or left while sighting. The effect of cant means that the bullet strikes to the right of the point of aim if the barrel is canted to the left and vice versa.

CARBINE: A sporting or military rifle that has a shorter barrel (generally 22` or less) and consequently is lighter weight than the average weapon.

CARTRIDGE: A complete round of ammunition containing bullet, powder, case, and primer.

CARTRIDGE CASE: A brass, steel, polymer, or aluminum tube that is used to house the bullet, powder, and primer.

CASE HARDENING: The process used to harden the surface metal while leaving the core soft. Usually applied to parts such as triggers, sears, and occasionally to frames and receivers.

CEASE FIRE: The command given to cause all firing to stop immediately.

CENTERFIRE: A form of cartridge case in which the primer is placed directly in the center of the base of the cartridge.

CHAMBER: (a) The compartment at the rear of the gun barrel that holds a charge or cartridge. (b) One of the compartments in the cylinder of a revolver. (c) To insert a round of ammunition into the chamber of a firearm.

CHAMBER PRESSURE: Pressure created by the rapid burning of a propellant (powder) within the chamber of a weapon during the instant after firing. Pressure is expressed in pounds per square inch (PSI), copper units of pressure (CUP), or megapascals (MPa) in the metric system.

CHARGE: (a) A given quantity of explosive. (b) The propellant for a bullet or shell. (c) To operate the action so as to chamber a round of ammunition, i.e. charge a weapon.

CHECKERING: A diamond-like pattern that is cut into the material of a firearm to improve grip or for appearance.

CHOKE: A constriction at the muzzle end of a shotgun barrel that changes the shot pattern, density, and dispersion. Choke is generally expressed as cylinder bore, improved cylinder, skeet modified, and full, in order of the most open to the most constricted. The greater the amount of choke. the tighter the shot pattern will be.

CLEAR: The act of removing all ammunition from a firearm.

CLIP: A device for holding cartridges together, usually to facilitate loading. The term clip is often used incorrectly to denote a magazine. However, magazines have feeding springs and clips do not. Magazines may sometimes be charged with clips.

COCK: To draw the hammer or cocking piece back into the firing position, either manually or by pressure on the trigger.

COCKED AND LOCKED: The condition of readiness of a self loading pistol wherein the round is chambered, the hammer is cocked, and the safety is engaged. Also known as Condition One.

COLOR CODE: Popularized by Jeff Cooper as an aid to understanding the mental conditioning needed for combat. The color code consists of the following four colors:

• White – Relaxed, unaware
• Yellow – Relaxed, alert
• Orange – Specific alert
• Red – Mental trigger

COMPENSATOR: A device used on the barrel of a firearm to reduce recoil or muzzle flip, or both.

CONDITIONS OF CARRY: A system devised by Jeff Cooper for describing the carry modes of semiautomatic pistols

• CONDITION ONE is cocked and locked, meaning that there is a round in the chamber, the hammer is cocked, and the safety is engaged.
• CONDITION TWO is hammer down with a round in the chamber, typically used for double action semi automatic firearms. 
• CONDITION THREE is carrying with a loaded magazine inserted in the pistol and no round in the chamber, also known as “Israeli Carry.”
• CONDITION FOUR is with the chamber empty and the magazine kept separate from the weapon.
• CONDITION ZERO is with a round in the chamber, the hammer cocked, and the safety disengaged.

CONTROLLED EXPANSION BULLET: Synonymous with hollow point bullet in police usage.

CONTROLLED PAIR: Two sighted shots fired as quickly and accurately as sight picture and trigger control will allow. 

COOK OFF: The unexpected discharge of a cartridge due to high barrel heat.

CORE: The internal part of a bullet that is covered by a jacket.

CRANE: The swinging unit which hinges the cylinder of a revolver with the frame.

CREEP: Trigger movement prior to sear release.

CRIMP: To mechanically fold inward the mouth of a cartridge case around the base of a bullet, holding it in place. 

CROSSHAIR: A type of reticle used in telescopic sights.

CROWN: The angled cut made at the muzzle end of a barrel to eliminate burrs, improve accuracy, and protect the rifling.

CRUISER READY (HOT STANDBY): The Condition 3 loading of a shotgun, so called because it is often used by many police departments to store a shotgun inside a police cruiser. The chamber is empty, the hammer is down, the magazine is full, the safety is off, and the action is unlocked. All that is required to ready the shotgun for firing is cycling the action.

C.U.P. (CUP) Copper Units of Pressure. The units by which cartridge breech pressures are measured through compression of a copper crusher gauge. Similar, but not identical, to the Pounds Per Square Inch (PSI) or megapascals (MPa) methods of measurement.

CYLINDER: A round steel block into which multiple chambers are bored to hold the cartridges in a revolver. 

D

DA: Double action. A term describing those pistol and revolver mechanisms where the hammer may be cocked, either by the trigger or by manually pulling it to the rear. In some pistols the action cocks the hammer after the first shot is fired using the trigger cocking mode.

DECAPPING: The act of removing a primer from a cartridge case during reloading.

DECOCKING LEVER: A frame or side mounted device on a double action pistol that is designed to safely lower the hammer when activated. On some pistols the decocking lever also acts as a safety, requiring that the device be decreased to lower the hammer then pushed back up to prepare for firing. 

DEDICATED PAIR: Two shots fired as fast as a sight picture can be obtained for each shot.

DISCONNECTOR: A safety device used to prevent a firearm from firing until the breech is completely closed. Also used to prevent fully automatic fire in a semi-automatic firearm.

DOUBLE FEED: A stoppage caused by a case failing to extract from the chamber and a round from the magazine is forced into the case head by the slide or bolt. Clearing this malfunction usually involves locking the slide or bolt to the rear, removing the magazine, clearing the chamber by racking the action several times, inserting a magazine, and sending the slide or bolt forward to chamber a fresh round. 

DRAM EQUlVALENT: The smokeless powder content of a modern shotshell, which is designated in terms of the equivalence of the archaic weight of black powder measured in drams.

DROP: (a) The vertical drop of a projectile in flight. (b) The distance measured from the line of sight to the top of the heel and comb of a gunstock.

DRY FIRE: Practice with an unloaded firearm.

DUD: A cartridge that has failed to function.

DUMMY CARTRIDGE: A cartridge without powder or primer.

E

EAR PLUG: Device used to protect the ear from damage caused by the sound of weapons firing. Also known as ear muffs or ear protection.

EFFECTIVE RANGE: The distance at which a shooter can reliably place hits on a target.

EJECTION: The process whereby a case or cartridge is thrown from a firearm by the ejector.

EJECTOR: A part in a firearm for throwing out spent shells or cartridges.

EJECTION PORT LOADING: Loading one round into an empty shotgun through the ejection port.

EXTRACTION: The process of removing a cartridge or case from the chamber of a firearm.

EXTRACTOR: A part in a firearm for removing a cartridge or case from the chamber.

EXTREME RANGE: The maximum distance a projectile will travel.

EYE RELIEF: The distance from the aiming eye to the rear sight or telescopic sight.

F

FEEDING: The process of driving live cartridges from the magazine into the path of the bolt or slide prior to chambering.

FEET PER SECOND: (fps) A unit of measure to express the velocity of a bullet.

FFL: Federal Firearms License, used to designate a firearms dealer.

FIELD STRIP: To disassemble the major components of a firearm for cleaning or inspection.

FIRING LINE: A line at which shooters are positioned for firing. Also used to describe the shooters on said line.

FIRING PIN: A rod or plunger in a firearm that strikes and thereby detonates a sensitive explosive (found in the primer or cartridge rim) to fire the propelling charge of powder.

FIRING POINT: A firing station on a firing line.

FLASH HOLE: A hole in the head of a cartridge case where the flash from the primer ignites the powder.

FLASH SIGHT PICTURE: Seeing the sights, specifically the front sight, in the center of the target for a brief period of time. Used to verify that the shooting stance and presentation have correctly aligned the firearm.

FLAT BASE: A type of base used on a bullet. Other types of bullet bases include Hollow Base, Bevel Base, and Boat Tail.

FLINCH: A sharp physical reaction that can cause shots to miss. A flinch is caused by anticipating the report or recoil of a firearm and is usually characterized by a sudden clenching of the hand.

FLOOR PLATE: The base or bottom of a magazine.

FMJ: Full Metal Jacket. A bullet usually completely enclosed in a hard metal jacket usually made of some form of copper or similar metal.

FOLLOWER: The part of a magazine where the cartridges rest for feeding .

FOLLOWER SPRING: The spring that elevates or functions the follower in a magazine. Also known as a magazine spring.

FORCING CONE: (a) The area on the breech of a revolver barrel that tapers into the rifling. (b) The constriction at the end of the chamber of a shotgun barrel that forces the load down from chamber to bore size.

FOREND: The part of the stock lying under the barrel in front of the action.

FRAME: A receiver. The part of a firearm that contains the action.

FOOT POUNDS: A measurement of energy commonly used to express the “power” of bullets. 

G

GAS OPERATED: An automatic or semi automatic firearm that uses part of the expanding gases upon firing to operate for the loading cycle. 

GAS PORT: A small hole in the barrel of a gas operated firearm through which powder gases escape to furnish power for the loading cycle.

GAUGE (or GAGE): The size of the bore of a firearm, especially a shotgun, determined by the number of spherical lead projectiles that fit into the bore from a pound of lead. 12 gauge means “twelve balls to the pound.”

GHOST RING: A type of aperture sight characterized by a large opening in a thin ring. Named this way because focusing on the front sight makes the rear aperture seem to disappear.

GRAIN (gr): A unit of weight. 7.000 grains to 1 pound. Bullets and propellant powder are commonly weighed in grains.

GRIP SAFETY: A device that prevents a firearm from being discharged unless depressed when the firearm is gripped properly.

GROUP: A cluster of shots on a target.

GUN: A mechanism consisting essentially of a barrel. receiver, and breech mechanism, using controlled explosives to shoot projectiles. Also known as a firearm. 

H

HAMMER: (a) The mechanism that strikes the firing pin or percussion cap in a firearm. (b) Firing two shots as quickly as possible with one sight picture.

HAND: (revolver) The operating lever that turns the cylinder. Also, PAWL.

HANDGUARD: A cover that encloses a rifle barrel to protect the hands from the heat generated during firing. 

HARDBALL: A term used to describe full metal jacket ammunition.

HARRIES TECHNIQUE: A low light shooting technique developed by Mike Harries that allows a flashlight to be easily incorporated into the Weaver shooting stance.

HEAD: Portion of a cartridge case that includes the rim, primer pocket, and primer.

HEAD STAMP: Markings on the head of a cartridge case that may indicate caliber, source, and date of manufacture.

HOLLOW POINT: A bullet with a cavity at the point.

I

IMPACT: The striking of a projectile on a target or surface.

IRON SIGHTS: Another word for metallic non-magnifying sights.

ISOSCELES STANCE: A handgun shooting stance generally characterized by standing facing the target squarely with both hands grasping the pistol and both arms straight, either with the elbows locked or slightly bent. Named because the position of the arms and chest resemble an isosceles triangle.

J

JACKET: The metal coating on the outside of a bullet.

JAM: A stoppage of the firing sequence due to improper loading, ejection, or similar malfunction.

JERK: The effort by the shooter to fire at the precise time the sights align with the target, usually resulting in a bad hit or a miss.

JEWEL: A process whereby certain parts of a firearm are polished in a circular pattern to give a high metallic luster.

JHC: Jacketed Hollow Cavity, another term for Jacketed Hollow Point bullets.

JHP: Jacketed Hollow Point (or hollowpoint). A partially jacketed bullet with an exposed lead point that is hollowed out in order to produce greater bullet expansion.

JSP: Jacketed Soft Point. A partially jacketed bullet with an exposed lead point designed to cause bullet expansion when it hits the target. 

K

KENTUCKY WINDAGE: A form of sighting and aiming usually employed when a firearm has non-adjustable sights or when the shooter does not have the time to make sight adjustments. Usually includes guessing elevation or windage and holding off the target as needed.

KEYHOLING: The tumbling of a bullet in flight. So named because of the easily identifiable ‘keyhole’ shaped hole a tumbling bullet often makes in a paper target.

KICK: A term used to describe the recoil of a firearm at the moment of firing.

KINETIC ENERGY: Energy inherent in a moving body due to motion. Also known in physics as the capacity of the moving object to perform work. Kinetic energy is frequently used as a comparative measure of the ‘power’ of various cartridges.

L

LAND: One of the raised ridges inside the bore of a rifled gun barrel. 

LEAD: (a) The action of aiming ahead of a moving target. (b) The distance between the moving target and the point at which the gun is aimed.

LEADING: Excessive lead deposits inside the grooves of a barrel. 

LEVER: (a) The moving handle that locks or unloads the actions in shotguns and double rifles. (b) The moving handle under the stock of lever action rifles that operates the action. 

LINE OF SIGHT: The straight line between an observer’s eye and a target.

LOAD: (a) To place ammunition in a gun. (b) A way to describe the combination of components that comprise a loaded cartridge.

LONGARM: A firearm that is not a handgun. such as a rifle. shotgun, or carbine. Also known as a long gun.

LR: An abbreviation for Long Rifle, as in .22LR ammunition.

M

MACHINE GUN: A firearm that continuously fires ammunition at a high rate when the trigger is pulled only once. The gun will continue to fire until the trigger is released or the ammunition supply is used up. A machine gun fires rifle ammunition, while a machine pistol or submachine gun fires pistol ammunition.

MAGAZINE: The part of a firearm that holds the ammunition ready for chambering and which may be detachable or non-detachable from the rest of the gun. A magazine has an internal spring, a clip does not.

MAGNUM: A term used for a firearm or cartridge with greater than normal power.

MAINSPRING: The part of a firearm that furnishes energy to the hammer or striker.

MAKE READY: A preparatory firing command meaning to load and protect the eyes and ears.

MAKE SAFE: A range command to instruct the student to render the firearm safe by applying the safety and removing the finger from the trigger or performing other firearm-specific functions such as decocking.

MALFUNCTION: The improper operation of any part of a firearm that may or may not stop it from firing.

MATCH GRADE: Firearms, ammunition, or equipment manufactured to shoot more accurately than similar standard or unaltered ammunition or firearms.

MINUTE OF ANGLE (MOA): The sixtieth part of a degree (1/60), which comes out to approximately one inch per 100 yards of distance. Commonly used calibration for gun sights and scopes.

MISFIRE: A momentary or permanent failure of a round of ammunition to fire after the igniting action has occurred.

MISS: Failing to hit what one is aiming at.

MODERN TECHNIQUE: A firearms training system developed by Jeff Cooper. The five elements of the Modem Technique are the Weaver Stance, the Flash Sight Picture, the Compressed Surprise Break, the Presentation, and a Heavy-Duty Pistol.

MOUTH: The open end of a cartridge case. 

MUSHROOM: The shape of a bullet that has expanded inside tissue.

MUZZLE: The forward end of a barrel.

MUZZLE BLAST: Sudden air pressure exerted at the muzzle of a weapon by the rush of hot gases and air when a gun is fired. 

MUZZLE VELOCITY: The speed of a bullet relative to the gun at the moment it leaves the barrel, usually expressed in feet per second (FPS).

N

NATURAL POINT OF AIM: The correct position of the body in relationship to the target. 

NEGLIGENT DISCHARGE The inadvertent firing of a weapon through improper handling or ignoring of safety rules. Often referred to as an Accidental Discharge or an Unintentional Discharge.

O

OPEN SIGHT A rear gunsight that has a notch.

OVER AND UNDER: A shotgun or rifle that has the barrels placed vertically, one on top of the other.

P

PARKERIZE: A dull gray colored firearms finish often used on military weapons. 

PATTERN: The distribution of shotgun pellets.

PEEP SIGHT: A rear gunsight that has a small hole into which the front sight is centered during aiming.

PENETRATION: The distance a projectile travels from the point of entry to the point where it stops.

PEPPER POPPER: A falling steel target created by John Pepper. Somewhat humanoid in shape and size, it may be adjusted so as to fall only after having received a sufficiently powerful blow.

PISTOL (also HANDGUN) (a) In popular usage, a firearm, usually short barreled, which is designed to be held and fired in one hand.. (b) More precisely, a firearm where the chamber is an integral part of the barrel, especially a semiautomatic pistol. (c) A Machine Pistol is a short barreled weapon firing pistol ammunition, which may be fired in the fully automatic mode.

POINT BLANK RANGE: This is the distance a projectile will travel before it drops to where a sight adjustment is required.

POST SIGHT: A vertical front sight. It may be metallic, open, or hooded. It may also be incorporated in several manners and shapes within telescopic sights.

POWDER: Short for gunpowder. Often found in the shape of flakes, cords, or balls, it can be used as a propellant in a cartridge.

POWER: The number of times the image of an object is magnified by use of a telescope. For example, 20X is a 20 times magnification and would be referred to as 20 power.

PRESENTATION The action by which a pistol is delivered from a holster to alignment with the target. Commonly referred to as the DRAW or DRAW STROKE.

PRESS CHECK: A method of determining if there is a round of ammunition in the chamber of a firearm. The action is opened slightly and the chamber is examined by sight or touch.

PRESSURE: The force exerted by burning gases against the cartridge case base of the bullet and chamber measured in PSI (pounds per square inch), CUP (copper units of pressure), or megapascals (MPa) in the metric system.

PRIMER: A sensitive explosive device that responds to percussion or some other disturbance to set off a propellant or an explosive. Composed of the primer compound, cup, and anvil.

PROJECTILE: A bullet of shot in flight after discharge from a firearm.

PRONE: Describes a number of shooting positions, all of which involve some form of lying down to shoot. Prone positions are used to add stability because they offer a lower profile. 

PROOF MARK: A stamp used by gun manufacturers to identify all weapons having met the standard prescribed pressure test.

PROPELLANT or PROPELLENT: Provides the energy for propelling a bullet. The propellant for most small arms ammunition is some form of gunpowder.

POINT SHOOTING: Firing without the aid of sights.

POUNDS PER SQUARE INCH: (PSI) A unit of measure used to evaluate the pressure in a chamber or cylinder. 

R

RAMP: An inclined plane designed to give proper elevation of front or rear sights.

RANGE: (a) A prescribed area where weapons firing is conducted. (b) The distance traveled by a projectile from the firearm to the target.

RECEIVER The basic unit of a firearm to which the barrel and other components are attached. Since the Gun Control Act of 1968, all receivers must be serial numbered.

RECOIL: The backward movement of a gun when fired, caused by the pressure of the propellant gas. Also the distance that a gun or part travels in this backward movement. A common term for recoil is “kick.”

RECOIL ENERGY: The force, measured in foot pounds or kilograms meters in the metric system, exerted rearward by a firearm when fired.

RECOIL PAD: A cushion attached to the butt of a shotgun or rifle to help absorb recoil.

RELOADING: Re-manufacturing fired ammunition.

RELOADING DIES: Tools used in reloading ammunition, such as the resizing, decapping, seating, and crimping dies.

RELOADING PRESS: A machine or device used in the reloading of ammunition.

REST: A support for a gun while firing.

RETICLE or RETICULE: A system of lines in the eyepiece of an optical instrument like a telescopic sight or scope. In a scope the reticle defines the line of sight for aiming. May also be referred to as crosshairs.

REVOLVER: A handgun with a rotating cylinder that carries several rounds of ammunition, each round being in a chamber that comes into line with the barrel before the round is fired. There are two types of revolvers, which are defined by how the cylinder is rotated and the firearm is cocked:
(a) DOUBLE ACTION revolvers may be hammer cocked by drawing the hammer manually to the rear (called single action tiring), or they may be trigger cocked by pressing the trigger to the rear thus rotating the cylinder, cocking. and releasing the hammer (called double action firing).
(b) SINGLE ACTION revolvers may only be fired by hammer cocking, which rotates the cylinder, and by then pressing the trigger.

RIB:  A piece of metal attached to the uppermost part of the slide or barrel. Used to raise the sighting plane, improve appearance, reduce barrel vibration, cool the sighting plane (ventilated rib), or provide a raised surface on which to mount a sight.

RICOCHET: The tendency of a bullet to skip, bounce, or fly off at an angle after striking an object or surface.

RIFLED SLUG: A spiral grooved, single ball projectile used in shotgun ammunition. 

RIFLING: The spiral longitudinal grooves cut in the bore of a barrel. Identified as being in two parts, the GROOVES and LANDS (the raised appearing sections between the grooves). Rifling is used to impart spin to a projectile, thus stabilizing it in flight.

RIM: The outer or extreme circumference on the head of a cartridge. Used for extracting or headspacing a cartridge. 

RIMFIRE: A cartridge design in which the priming mixture is placed in a fold in the head of the cartridge case, as in .22 Long Rifle ammunition.

RIMLESS: A cartridge case design in which the case bears no rim about the head.

S

SAFETY: A mechanical device on a firearm that locks all or part of the firing mechanism in order to keep it from firing.

SCOPE: Short for telescope or telescopic sight.

SEAR: The part of the action of a firearm that engages the hammer or striker to hold it in a cocked position.

SECTIONAL DENSITY: The weight of a bullet in grams, divided by its diameter.

SEMIAUTOMATIC: A firearm that uses part of the force of the exploding cartridge to extract the empty case and chamber the next round, but requires a separate press on the trigger to fire each round.

SHELL: A cartridge case.

SHOT: The round projectiles used in the manufacture of shotgun ammunition.

SHOTSHELL: Multiple projectile cartridge commonly used with shotguns. Shotshells may also be used in handguns and rifles.

SIDE BY SIDE: A firearm with two barrels placed horizontal to each other. Usually a shotgun or double rifle.

SIGHT: A device through which the target is viewed to give proper elevation and direction.

SIGHT ALIGNMENT: When the front and rear sights are brought into correct adjustment with the shooter’s eye.

SIGHT PICTURE: Seeing the sights in proper alignment with the target.

SIGHT RADIUS: The distance from the front to the rear sight.

SILENCER (SUPPRESSOR): A device fixed to the muzzle that baffles the propelling gases from each shot, thus lowering the volume. A suppressor rarely, if ever, renders the firearm soundless.

SLACK: The amount of movement in a trigger mechanism before it engages the sear.

SLING: A leather, web, or nylon strap used to help support a rifle during firing.

SMOKELESS POWDER: A nitrocellulose base gunpowder sometimes compounded with nitroglycerin.

SMOOTHBORE: A firearm with no rifling in the barrel, such as a shotgun or musket.

SOLVENT: A liquid capable of dissolving powder residue and used in the cleaning of firearms.

SPEED RELOAD: The action taken to replace the ammunition supply of an empty or partially loaded weapon as quickly as possible in order to maintain the ability to fire.

SPITZER: A type of pointed bullet designed to give better stability during flight.

SPOTTING SCOPE: A telescope used by shooters or hunters to check hits or locate game.

STIPPLING: The roughing of metal to improve gripping surfaces.

STOCK: The pieces of wood, fiberglass, plastic, or rubber attached to a firearm to allow it to be grasped and aimed.

SWC (SEMI-WADCUTTER): A bullet with a flat ended nose section and a full caliber cutting shelf.

T

TACTICAL RELOAD: Reloading a firearm with a partially depleted ammunition supply in order to return it to full capacity while retaining the ammunition remaining. 

TAP-RACK-BANG: Immediate action taken when a stoppage has occurred in magazine fed weapons. The steps are TAP the magazine to insure it is seated, RACK the action to feed or replace a cartridge in the chamber, and, assuming it is appropriate, BANG means to fire the weapon. 

TARGET: The object at which the shooter is aiming.

TARGET READING: Examining the group of shots on a target so as to analyze the shooting stance, sight alignment, sight picture, and trigger control.

TRAJECTORY: The curve on the vertical plane traced by a bullet after firing.

TRIGGER: The part of the gun that releases another mechanism and causes firing to occur when pressed. 

TRIGGER GUARD: The part of a firearm that helps prevent trigger damage or accidental firing.

TRIGGER PRESS or TRIGGER CONTROL: Moving the trigger until the sear disengages, the hammer or striker goes forward, and the weapon fires, without disturbing the sight alignment or sight picture.

TRIGGER PULL: (a) The amount of weight necessary to activate the trigger. (b) The length of travel during a trigger press.

TRIGGER RESET: The action of holding the trigger to the rear after the sear breaks and during the cycling of the weapon, then releasing the trigger only to sear re-engagement.

TRIGGER TAKE-UP: (Or slack) is any motion of the trigger backwards or towards you which does not engage the mainspring or cause the sear to move.

TWIST: The distance in inches a bullet travels through the barrel to make one complete revolution. Expressed as a ratio such as 1:16, meaning one revolution in 16 inches.

U

UNLOAD: A range command given to remove all ammunition from the firearm, followed by visually inspecting to verify that the magazine and chamber are empty, followed by physically verifying the status of the gun by feeling into the action and chamber.

W

WAD: A material used in shot shells or in the loading of muzzleloading firearms to retain the powder or shot charge and to control gases.

WC (WADCUTTER): A flat pointed bullet designed to cut a clean hole through a target.

WEAVER STANCE: Developed by Jack Weaver, it is a two handed method used to aim and shoot a handgun. The Weaver Stance incorporates isometric tension to stabilize the firearm.

WINDAGE: (a) Moving the windage adjustment of the sights of a firearm to compensate for wide shots caused by either wind or misalignment. (b) The lateral drift of a bullet in flight caused by wind. 

Z

ZERO: (a) To adjust the sight settings of a gun by calibrating the results of firing. (b) Aligning the sights so that the bullet will strike the target at the point of aim.

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