Welcome to our Comprehensive Firearms Glossary, your go-to resource for understanding the essential terms and concepts in the world of firearms. Whether you’re a seasoned enthusiast or a beginner just starting your journey, this glossary is designed to provide clear and concise definitions of key terminology related to various firearms, including AR-10, AR-15, and many more.

In this glossary, you’ll find detailed explanations of AR components, mechanisms, and terminology used in the firearms industry. Each term is carefully defined to enhance your knowledge and help you navigate the complex language of firearms with confidence. Additionally, we’ve included images and internal links to related articles, allowing you to dive deeper into specific topics and expand your understanding further.

Explore our glossary to familiarize yourself with the language of firearms, improve your expertise, and become a more informed member of the firearms community.

Alphabetical Index

To make it easy for you to find specific terms, we've organized our glossary alphabetically. Click on a letter to jump to that section of the glossary.

Glossary Entries

A

Accurize, Accurizing
The process of modifying a firearm to improve its accuracy. This can include adjustments to the barrel, trigger, sights, and other components.
Ackley Improved
A series of wildcat cartridges designed by P.O. Ackley to improve the performance of standard cartridges by increasing case capacity and improving ballistics. Ackley Improved cartridges often have steeper shoulder angles and reduced body taper.
ACP (Automatic Colt Pistol)
A designation for a series of cartridges designed by John Browning for Colt semi-automatic pistols. Examples include the .45 ACP, .380 ACP, and .25 ACP.
Action
The mechanism of a firearm that handles the ammunition (loading, firing, and ejection). Common types of actions include bolt action, lever action, pump action, and semi-automatic action.
Adjustable Sight
A type of sight that can be adjusted for elevation (up and down) and windage (left and right) to improve shooting accuracy at various distances.
Ammunition
The projectiles and propelling charges used in firearms. Ammunition or ammo consists of cartridges, which include a bullet, casing, powder, and primer.
AR
Stands for ArmaLite Rifle, after the company that developed the original design in the 1950s. Commonly associated with AR-15 style rifles.
AR-10
AR-10 rifles, designed by Eugene Stoner in the 1950s, feature a larger caliber than AR-15.
AR-15
A lightweight, magazine-fed, gas-operated rifle, also designed by Eugene Stoner.
Assault Rifle
A selective-fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are capable of both semi-automatic and automatic fire.
Assault Weapon
A term used in some laws to describe semi-automatic firearms with certain features that are similar to those found on military weapons. The definition of an assault weapon can vary by jurisdiction.
Automatic
A firearm capable of firing continuously while the trigger is held down, as opposed to semi-automatic firearms, which fire one shot per trigger pull.
Automatic Fire
A mode of firearm operation where the firearm continues to fire as long as the trigger is held down, automatically cycling the action to load and fire subsequent rounds.
Automatic Pistol
A type of semi-automatic handgun that uses the energy of the fired cartridge to cycle the action and load the next round into the chamber.
Automatic Rifle
A rifle capable of automatic fire, meaning it can continuously fire rounds as long as the trigger is held down. These are typically used in military applications.

B

Back Bore, Backbored Barrel
A shotgun barrel that has been machined to a larger internal diameter than standard, which can reduce recoil and improve shot patterns.
Ballistic Coefficient (BC)
A measure of a bullet’s ability to overcome air resistance in flight. A higher BC indicates a more aerodynamically efficient bullet.
Ballistics
The science of the motion of projectiles in flight, including the behavior of bullets, rockets, and other projectiles. Ballistics can be divided into internal, external, and terminal ballistics.
Bandolier or Bandoleer
A shoulder-belt with loops or pockets for carrying ammunition.
Barrel
The long metal tube through which a projectile is fired. The barrel guides the projectile and imparts spin to stabilize it in flight.
Barrel Nut
A component used to secure the barrel to the receiver in certain firearms, particularly AR-style rifles.
Barrel Twist Rate
The rate at which the rifling inside the barrel twists, expressed in inches per turn (e.g., 1:7).
Battle Rifle
A military service rifle that fires a full-power rifle cartridge, such as the 7.62x51mm NATO, and is typically semi-automatic or fully automatic.
Bayonet Lug
A mounting point on a firearm, usually near the muzzle, to which a bayonet can be attached.
Belt
A series of linked ammunition, typically used in machine guns, allowing for continuous feeding of rounds.
Belted Magnum or Belt
A type of cartridge case design featuring a belt around its base, providing headspacing and allowing for more reliable feeding and extraction.
Bipod
A two-legged support device attached to a firearm, used to stabilize the weapon during firing.
Black Powder
A traditional gunpowder made from a mixture of saltpeter, sulfur, and charcoal. It was used as a propellant in firearms and fireworks before being largely replaced by smokeless powder.
Black Powder Substitute
Modern propellants designed to mimic the performance of traditional black powder but with less fouling and smoke. Examples include Pyrodex and Triple Seven.
Blank
A type of cartridge that contains gunpowder but no bullet. Blanks are used for training, signaling, and ceremonial purposes.
Blank-Firing Adapter
A device attached to the muzzle of a firearm to allow it to cycle properly when firing blank ammunition.
Blowback
A type of firearm action where the pressure from the fired cartridge is used to push the bolt or slide backward, ejecting the spent case and chambering a new round.
Blow-Forward
A less common type of firearm action where the barrel moves forward as the bullet is fired, rather than the bolt moving backward.
Bluing or Blueing
A chemical process used to create a corrosion-resistant, bluish-black oxide coating on steel firearms, providing both protection and aesthetic appeal.
Bolt Action
A type of firearm mechanism where the bolt is manually operated by the shooter to load and unload cartridges. Bolt action rifles are known for their accuracy and reliability.
Bolt Bore Rope
A cleaning tool consisting of a flexible, pull-through rope used to clean the bore of a firearm. Ripcord® is a well-regarded brand for bolt bore ropes, also known as bore snakes.
Bolt Carrier Group (BCG)
The assembly of parts that facilitates the firing of a round in AR-style rifles known as the bolt carrier group.
Bolt Thrust
The rearward force exerted on the bolt of a firearm when a cartridge is fired, caused by the pressure of the expanding gases.
Bore
The interior of the barrel of a firearm through which the projectile travels when fired. The diameter of the bore is referred to as the caliber.
Boresight
A method of aligning the firearm’s sights with the bore of the barrel to ensure accurate shooting. Boresighting is typically done before fine-tuning with live fire.
Box Magazine
A detachable magazine that holds cartridges in a rectangular or square box shape, commonly used in rifles and pistols.
Brass
Empty cartridge cases, often collected for reloading. Brass is also the material commonly used for cartridge cases due to its durability and corrosion resistance.
Break-Action
A type of firearm action where the barrel(s) are hinged and can be “broken” open to expose the chamber(s) for loading and unloading. Commonly found in shotguns and some rifles.
Breech
The rear part of the firearm’s barrel where the cartridge is inserted. Breech-loading firearms load ammunition at the rear end of the barrel.
Breech Pressure
The pressure exerted by the burning propellant within the chamber of a firearm when a round is fired. High breech pressure is essential for proper bullet propulsion but must be managed to prevent damage or injury.
Browning
A process for treating metal surfaces to improve corrosion resistance and aesthetic appearance, also a term used to refer to firearms designed by John Browning.
Buckshot
A type of shotgun ammunition that contains multiple large lead pellets. Buckshot is commonly used for hunting and self-defense.
Buffer
A component in a firearm, particularly in semi-automatic and automatic rifles, such as the buffer in AR-style rifles, that absorbs recoil and reduces the impact of moving parts to ensure smooth cycling.
Bullet
The projectile that is fired from a firearm. Bullets are typically made of lead, often with a copper jacket, and come in various shapes and sizes to suit different purposes.
Bullpup
A firearm design in which the action and magazine are located behind the trigger group, resulting in a shorter overall length without sacrificing barrel length.
Burst Mode
A firing mode on some automatic firearms that allows the shooter to fire a predetermined number of rounds (usually two or three) with a single trigger pull.
Button Rifling
A method of creating rifling in a barrel by pressing or pulling a hardened steel button with the rifling pattern through the barrel to imprint the grooves.

C

Caliber
The diameter of the bore of a firearm or the diameter of the cartridge used in the firearm. Caliber is usually measured in inches or millimeters.
Caplock
An ignition system for muzzleloading firearms that uses percussion caps to ignite the powder charge, replacing the earlier flintlock mechanism.
Carbine
A short-barreled rifle that is typically lighter and more compact than a standard rifle, often used by cavalry, paratroopers, and special forces.
Carbon Buildup
A common issue in firearms where carbon deposits accumulate in the barrel, gas system, and other parts of the firearm as a result of firing. These deposits can affect the performance and reliability of the firearm if not regularly cleaned and maintained. Proper cleaning and maintenance procedures are essential to prevent and remove carbon buildup. For more detailed information, read our article Unmasking the Hidden Dangers: The Truth About Carbon Buildup in Firearms.
Cartridge
A complete unit of ammunition consisting of a case, primer, powder, and bullet. Cartridges are used in both firearms and artillery.
Caseless Ammunition
A type of ammunition that does not have a separate cartridge case. The propellant and projectile are combined into a single unit, reducing weight and potentially increasing the rate of fire.
Casing
The container that holds all the components of a cartridge together: the bullet, powder, and primer. Casings are typically made of brass, steel, or aluminum.
Casket Magazine
A high-capacity magazine designed to hold more rounds than standard box magazines, often featuring a unique shape to accommodate the extra ammunition.
Centerfire
A type of cartridge that has the primer located in the center of the cartridge base. Centerfire cartridges are more common in modern firearms due to their reliability and ability to handle higher pressures.
Chain Gun
A type of machine gun that uses an external power source, typically an electric motor, to cycle the action and feed ammunition. Chain guns are known for their reliability and consistent rate of fire.
Chamber
The part of the firearm’s barrel or cylinder where the cartridge is placed before being fired. In a revolver, the chamber is located in the cylinder.
Chambering
The process of loading a cartridge into the chamber of a firearm, ready for firing.
Charger
A device used to quickly load multiple rounds into a firearm’s magazine or internal magazine. Chargers are commonly used with bolt-action rifles.
Charging Handle
A component used to manually cycle the bolt carrier group of a firearm. Shop Charging Handles
Choke
A constriction at the muzzle end of a shotgun barrel that shapes the spread of the shot to improve accuracy and range. Different choke types include full, modified, and improved cylinder.
Chrome Lining
A type of barrel coating that increases durability and ease of cleaning.
Clip
A device used to store multiple rounds of ammunition together as a unit, ready for insertion into the magazine or chamber of a firearm. Clips are often used for fast reloading.
Cock
The action of preparing a firearm to fire by moving the hammer or striker to the rear, usually accomplished by pulling back on the slide, bolt, or hammer.
COL (Cartridge Overall Length)
The total length of a loaded cartridge from the base of the case to the tip of the bullet. COL is an important specification for ensuring proper feeding and chambering in firearms.
Collimator Sight
A type of non-magnifying reflector sight that allows the shooter to aim by looking through a lens and aligning a reticle with the target. Collimator sights are often used in military and competitive shooting.
Combination Gun
A firearm that has more than one type of barrel, typically a rifle barrel and a shotgun barrel, allowing the shooter to use different types of ammunition in the same gun.
Cooking Off
A dangerous condition where a cartridge is ignited by the heat of a firearm’s barrel or chamber rather than by the firing mechanism, typically occurring after sustained rapid fire.
Cordite
An early type of smokeless propellant used in firearms and artillery, composed of nitroglycerin, nitrocellulose, and petroleum jelly. Cordite was widely used by the British military in the early 20th century.
CQB (Close Quarters Battle)
Combat that takes place in confined spaces, such as buildings or urban environments, where engagements occur at very short ranges. CQB tactics often emphasize speed, surprise, and aggressive action.
Cylinder
The rotating part of a revolver that contains multiple chambers, each holding a cartridge. The cylinder advances each time the hammer is cocked, aligning a new chamber with the barrel.
Cylindro-conoidal Bullet
A type of bullet with a cylindrical body and a conical point, designed to improve aerodynamics and stability in flight. These bullets are commonly used in rifled firearms.

D

Damascus Barrel or Damascus Twist
A type of barrel made by twisting and welding strips of iron and steel together, resulting in a distinctive pattern. Damascus barrels were commonly used in older firearms, especially shotguns.
Delayed Blowback
A type of firearm action that delays the opening of the breech until the pressure has dropped to a safe level. This is typically achieved through mechanical means such as rollers or levers.
Derringer
A small, easily concealable handgun with one or two barrels. Derringers are typically single-shot or double-barreled and are known for their compact size.
Direct Impingement
A gas-operated system used in some semi-automatic and automatic firearms where the propellant gases are directed from the barrel directly to the bolt carrier to cycle the action. The AR-15 rifle is a well-known example.
Disassembly
The process of taking apart a firearm for cleaning, maintenance, or repair.
Discharge
The act of firing a firearm. Discharge can also refer to the release of gas or powder from a cartridge or propellant.
Doglock
A type of lock mechanism used in early flintlock firearms that features an external catch or “dog” to secure the cock (hammer) and prevent accidental discharge.
Double Action (DA)
A type of firearm action where pulling the trigger both cocks and releases the hammer, resulting in a longer and heavier trigger pull compared to single action. Double action is commonly found in revolvers and some semi-automatic pistols.
Double Action Revolver
A type of revolver where pulling the trigger both cocks and releases the hammer, resulting in a longer and heavier trigger pull compared to single action. This allows for faster follow-up shots.
Double-Barreled Shotgun
A shotgun with two parallel barrels, allowing for two shots to be fired in quick succession. Double-barreled shotguns can be side-by-side or over-and-under configurations.
Double Rifle
A type of rifle with two parallel barrels, typically used for hunting large game. Double rifles can be either side-by-side or over-and-under configurations.
Double Stack
A magazine design where the cartridges are staggered in two columns, allowing for a higher capacity compared to a single stack magazine. Double stack magazines are commonly used in semi-automatic pistols.
Double Tap
A shooting technique where two shots are fired in rapid succession at the same target, aiming to increase the likelihood of hitting the target and causing more damage.
Drilling
A type of combination gun with three barrels, usually two shotgun barrels and one rifle barrel. Drillings are versatile firearms often used for hunting.
Drop-In Trigger
A pre-assembled trigger unit that can be easily installed in a firearm.
Drum Magazine
A type of magazine that holds a large number of rounds in a cylindrical or drum-like shape, allowing for extended firing without reloading.
Dry Fire
The practice of firing a firearm without live ammunition. Dry firing can be used for training and practice but should be done with caution as it can potentially damage some firearms.
Dum-Dum
A type of expanding bullet designed to inflict greater damage upon impact. Dum-dum bullets have a hollow point or soft point that causes them to expand on contact with a target.
Dummy
A non-functional replica of a cartridge used for training, practice, or testing the action of a firearm without the risk of accidental discharge. Dummy rounds are also used for function checking and dry firing.
Dust Cover
A cover designed to protect the action of a firearm from dirt, dust, and debris. Dust covers are commonly found on AR-15 rifles and other firearms to ensure reliable operation in harsh conditions.

E

Ear Protection
Devices such as earplugs or earmuffs designed to protect the shooter’s hearing from the loud noise produced by firing firearms. Ear protection is essential for preventing hearing damage.
Effective Range
The maximum distance at which a firearm or projectile can achieve the desired effect, such as hitting a target with sufficient accuracy and power. Effective range varies based on the firearm, ammunition, and shooting conditions.
Ejector
A component that expels spent cartridges from the firearm’s chamber.
Electronic Firing
A method of firearm ignition that uses an electric current to ignite the primer or propellant, rather than a mechanical firing pin. Electronic firing can provide faster lock times and potentially improve accuracy.
Eye Relief
The distance between the shooter’s eye and the rear lens of a scope or other optical sight at which the shooter can see a full, clear image. Proper eye relief is important for comfort and to avoid injury from recoil.
Expanding Bullet
A type of bullet designed to expand upon impact, increasing its diameter and creating a larger wound channel. Expanding bullets, such as hollow points, are commonly used in hunting and self-defense to maximize stopping power.
Extractor
A component that pulls the spent cartridge from the chamber after firing.

F

Fail-to-Fire
A malfunction where the firearm does not discharge when the trigger is pulled, often due to a problem with the primer or firing mechanism.
Falling Block Action (also known as Sliding-Block Action)
A type of single-shot firearm action where the breechblock slides vertically to open and close the breech, allowing for the loading and unloading of cartridges.
Ferritic Nitrocarburizing
A surface hardening process that enhances the wear and corrosion resistance of steel parts, commonly used in firearm components such as barrels and slides.
Feed Ramp
A sloped surface that guides a cartridge from the magazine into the chamber of a firearm during the loading process.
Field Strip
The process of disassembling a firearm into its major components for cleaning, maintenance, or inspection, typically without the use of tools.
Fire Forming
The process of reshaping a cartridge case to fit a specific chamber by firing it in the chamber. This technique is often used in custom or wildcat cartridge creation.
Firearm
A weapon that launches one or more projectiles at high velocity through the confined burning of a propellant. Firearms include handguns, rifles, shotguns, and other guns.
Firing Pin
A part of the firearm that strikes the primer of a cartridge to ignite the propellant. Shop Firing Pins
Flash Suppressor
A device attached to the muzzle of a firearm that reduces the visible signature of the muzzle flash when a round is fired, helping to conceal the shooter’s position and preserving night vision.
Forcing Cone
The tapered section of a firearm barrel just ahead of the chamber that guides the bullet into the rifling, ensuring proper alignment and sealing.
Flintlock
An ignition system for muzzleloading firearms that uses a piece of flint to strike a steel frizzen, creating sparks that ignite the powder charge. Flintlocks were commonly used in the 17th to 19th centuries.
Fluted Barrel
A barrel with longitudinal grooves cut into its surface to reduce weight, increase surface area for cooling, and potentially improve rigidity.
Fluted Chamber
A chamber with longitudinal grooves cut into its walls, typically found in some blowback-operated firearms to aid in extraction by reducing the surface area in contact with the cartridge case.
Fouling
The accumulation of unwanted material on the surface of the firearm’s bore and action, typically consisting of residues from burnt powder, lead, copper, and carbon. Fouling can affect the performance and accuracy of a firearm and requires regular cleaning.
Fouling Shot
The first shot fired from a clean firearm, which can help settle the barrel and improve accuracy for subsequent shots by leaving a thin layer of fouling in the bore.
Forward Assist
A device on some firearms, particularly AR-15 style rifles, that allows the shooter to manually close the bolt and ensure it is fully locked in place.
Frangible
A type of bullet designed to disintegrate into small fragments upon impact, reducing the risk of over-penetration and ricochets. Frangible bullets are often used in training and close-quarters environments.
Free Gun
A firearm, typically a machine gun, that is mounted in such a way that it can be moved freely in any direction by the operator.
Frizzen
A component of a flintlock ignition system that serves as both a steel striking surface for the flint and a cover for the priming powder in the pan. When struck by the flint, the frizzen creates sparks to ignite the powder.

G

Gas Bleed
A system in firearms where a portion of the propellant gases is diverted from the barrel to operate the action, usually found in gas-operated firearms.
Gas Block
A component that regulates the flow of gas from the barrel to the gas tube in a gas-operated firearm. Shop Gas Blocks
Gas Check
A metal cup or disc placed at the base of a lead bullet to prevent gas cutting and improve accuracy, especially in high-velocity loads.
Gas Key
A part of the bolt carrier group that interfaces with the gas tube to cycle the firearm.
Gas-Operated Reloading
A method of firearm operation where the energy from the propellant gases is used to cycle the action, eject the spent cartridge, and load a new round. Examples include the AR-15 and AK-47 rifles.
Gatling Gun
A type of early machine gun invented by Richard Gatling, featuring multiple rotating barrels that are manually operated by a crank to achieve a high rate of fire.
Gauge
A measurement used to describe the bore diameter of a shotgun. The gauge number is determined by the number of lead balls of that diameter that equal one pound. For example, a 12-gauge shotgun has a bore diameter such that 12 lead balls of that size weigh one pound.
General Purpose Machine Gun (GPMG)
A versatile machine gun designed for various roles, including infantry support, vehicle mounting, and aircraft armament. Examples include the M240 and the FN MAG.
Glock
A popular brand of polymer-framed, semi-automatic pistols known for their reliability, durability, and simplicity. Glocks are widely used by law enforcement and civilians around the world.
Grain
A unit of measurement for the weight of bullets and powder, where 1 grain is equal to 1/7000th of a pound. Bullet weights are commonly expressed in grains.
Grip
The part of a firearm that is held by the shooter’s hand. Grips can be made of various materials and may feature texturing or ergonomic designs to improve control and comfort.
Grip Safety
A safety mechanism on some firearms, typically located on the backstrap of the grip, which must be depressed by the shooter’s hand to allow the firearm to discharge. This feature is common on the M1911 pistol.
Gun Serial Number
A unique identifier assigned to a firearm by the manufacturer. Serial numbers are used for record-keeping, tracing, and identification purposes.
Gunpowder
A chemical mixture used as a propellant in firearms. Traditional gunpowder, also known as black powder, has largely been replaced by smokeless powder, which produces less smoke and residue.

H

Hair Trigger
A trigger mechanism that requires very little pressure to release the sear and fire the firearm. Hair triggers are often used in competitive shooting to enhance accuracy by minimizing trigger pull effort.
Hammer
A component that strikes the firing pin or cartridge primer in a firearm.
Hammer Bite
An injury caused when the hammer of a firearm pinches or cuts the shooter’s hand, usually occurring in semi-automatic pistols when the slide cycles backward.
Hang Fire
A delay between the pulling of the trigger and the ignition of the propellant in a cartridge, caused by slow-burning primer or other ignition issues. Hang fires can be dangerous as the firearm may discharge unexpectedly.
Half-Cock
A safety position on a firearm’s hammer where the hammer is partially cocked and cannot strike the firing pin or primer. This feature is common on older lever-action and single-action revolvers.
Handgun
A firearm designed to be held and fired with one hand. Handguns include pistols and revolvers, and are typically used for self-defense, law enforcement, and sport shooting.
Headspace
The distance between the base of the cartridge and the part of the firearm that stops its forward motion (usually the bolt face or breech face). Proper headspace is crucial for the safe and reliable functioning of a firearm.
Headstamp
Markings on the base of a cartridge case that provide information about the manufacturer, caliber, and sometimes the year of production. Headstamps are used for identification and quality control.
Heavy Machine Gun
A machine gun designed to fire large-caliber rounds, typically 12.7mm or larger, used for anti-material and heavy support roles. Examples include the M2 Browning .50 caliber machine gun.
High Brass
Shotgun shells with a taller brass base, indicating a higher-powered load. High brass shells are often used for hunting and shooting heavier loads.
Hollow Point
A type of bullet with a hollowed-out tip designed to expand upon impact, increasing its diameter and creating a larger wound channel. Hollow point bullets are commonly used for self-defense and hunting.
Holographic Weapon Sight
An advanced optical sight that uses a holographic reticle to provide fast target acquisition and accuracy. Unlike traditional red dot sights, holographic sights project the reticle onto a holographic film, offering advantages in parallax and target engagement.

I

Improved Cartridge
A cartridge that has been modified to enhance its performance, usually by increasing case capacity, altering the shoulder angle, or optimizing the overall dimensions for better ballistics. Examples include Ackley Improved cartridges.
IMR Powder (Improved Military Rifle)
A brand of smokeless powder used in reloading ammunition, known for its consistent burn rates and performance in a wide range of rifle calibers. IMR powders are commonly used by reloaders for both military and civilian applications.
Improvised Firearm
A homemade or crudely manufactured firearm, often constructed from readily available materials. Improvised firearms are typically made in environments where access to conventional firearms is restricted.
Internal Ballistics
The study of the processes occurring inside a firearm from the moment the primer is struck until the bullet exits the barrel. Internal ballistics examines the ignition of the propellant, the pressure generated, and the bullet’s movement through the barrel.
Iron Sights
A set of simple, non-optical sighting devices typically used on firearms.

J

Jacket
A metal covering on a bullet, usually made of copper, that reduces lead fouling in the barrel.
Jam
A malfunction in which a firearm fails to cycle properly, often resulting in a cartridge or spent case becoming stuck in the action. Common causes of jams include improper loading, dirt, or mechanical failure.
Jeweling
A decorative machining process that creates a pattern of overlapping circles on metal surfaces, often applied to the bolts and other visible parts of firearms to enhance their appearance and reduce friction.

K

Keyhole or Keyholing
A term used to describe a bullet that tumbles in flight and strikes the target sideways, creating a keyhole-shaped entry hole. Keyholing can indicate issues with barrel rifling, bullet stability, or improper ammunition.
KeyMod
A universal interface system for firearm accessory attachment.
Khyber Pass Copy
A term for crude, handmade firearms produced in the Khyber Pass region of Pakistan and Afghanistan. These copies often imitate popular firearm designs but are made with lower quality materials and craftsmanship.
Kick
A colloquial term for the recoil or backward movement of a firearm when it is discharged. The kick can vary in intensity depending on the caliber of the ammunition, the weight of the firearm, and other factors.

L

Lands
The raised portions of rifling in a barrel.
Laser Sight
An aiming device that projects a laser beam onto the target, providing a visual indicator of where the bullet is likely to impact. Laser sights are commonly used for quick target acquisition and in low-light conditions.
Leading
The accumulation of lead residue in the barrel of a firearm, usually from firing lead bullets. Leading can affect accuracy and requires regular cleaning to prevent buildup.
Length of Pull
The distance from the trigger to the end of the buttstock on a rifle or shotgun. Proper length of pull is important for shooter comfort and control.
Lever Action
A type of firearm action in which the operation of a lever located around the trigger guard area cycles the action, ejects a spent cartridge, and chambers a new one. Lever action firearms are commonly associated with rifles and are known for their reliability and ease of use.
Light Machine Gun
A type of machine gun designed to be carried and operated by a single soldier, typically firing intermediate or full-power cartridges. Light machine guns provide sustained fire support for infantry units. Examples include the M249 SAW.
Live Fire Exercise (LFX)
A training exercise where participants use live ammunition to practice real-world combat scenarios. Live fire exercises help improve marksmanship, tactical skills, and overall readiness.
Lock
The mechanism in a firearm that holds the hammer or firing pin at full cock and releases it when the trigger is pulled. The lock can include components such as the trigger, sear, and hammer.
Lug
A projection on a firearm component, such as the bolt or barrel, that engages with a corresponding recess to lock parts together securely. Lugs are essential for maintaining the structural integrity of the firearm during firing.

M

Machine Gun
A fully automatic firearm designed to fire bullets in rapid succession from a magazine or belt feed. Machine guns are capable of sustained fire as long as the trigger is held down.
Machine Pistol
A type of handgun capable of fully automatic fire. Machine pistols are often compact and can be difficult to control due to their high rate of fire. Examples include the Glock 18 and the Beretta 93R.
Magazine
A device that holds and feeds ammunition into a firearm.
Magnum
A designation for a firearm cartridge that has increased power compared to standard cartridges of the same caliber. Magnum cartridges generate higher velocity and energy, often used for hunting and long-range shooting.
Match Grade
A term used to describe firearms, ammunition, or components that meet high standards of accuracy and performance, suitable for competitive shooting. Match grade products are often precision-manufactured to tight tolerances.
Matchlock
An early type of firearm ignition system where a burning match cord is brought into contact with the priming powder to ignite the main charge. Matchlocks were used before the development of flintlock and percussion cap systems.
Medium Machine Gun
A type of machine gun that is heavier than a light machine gun but lighter than a heavy machine gun, typically firing full-power rifle cartridges. Medium machine guns are used for sustained fire support. Examples include the M240 and PKM.
Mine Shell
A type of shell used in anti-aircraft and anti-personnel roles, designed to explode and release a large number of fragments or submunitions upon detonation.
Misfire
A failure of a firearm to discharge when the trigger is pulled, usually due to a problem with the primer or the firing mechanism. Misfires can occur with both cartridges and percussion caps.
Muzzle
The end of the barrel from which the projectile exits a firearm. The muzzle is often threaded to accommodate attachments such as suppressors, flash suppressors, or muzzle brakes.
Muzzle Brake
A device attached to the muzzle of a firearm to redirect propellant gases and reduce recoil. Shop Muzzle Brakes
Muzzle Energy
The kinetic energy of a bullet as it exits the muzzle of a firearm, usually measured in foot-pounds or joules. Muzzle energy is a key factor in determining the potential impact and stopping power of a bullet.
Muzzle Velocity
The speed at which a projectile leaves the barrel of a firearm, typically measured in feet per second (fps) or meters per second (m/s). Muzzle velocity is influenced by factors such as barrel length, ammunition type, and propellant charge.

N

NATO
An abbreviation for the North Atlantic Treaty Organization, often used in the context of ammunition standardized by NATO countries.
Neck
The tapered section of a cartridge case that holds the bullet in place. The neck transitions from the wider body of the case to the narrower mouth, which grips the bullet.
Necking Down or Necking Up
The process of resizing the neck of a cartridge case to accept a smaller (necking down) or larger (necking up) diameter bullet. This is commonly done to create custom or wildcat cartridges with specific performance characteristics.
Nitroglycerin
A highly explosive compound used as a propellant in smokeless powders and other explosives. Nitroglycerin is more stable and powerful than traditional black powder, making it a key ingredient in modern ammunition.
NRA (National Rifle Association)
A U.S. organization dedicated to advocating for the rights of gun owners, promoting firearm safety, and providing training and education. The NRA is one of the most influential pro-gun advocacy groups in the United States.

O

Obturate
The sealing of the bore to prevent the escape of gases around the projectile, ensuring maximum efficiency and pressure. This can be achieved by the expansion of the bullet base or through the use of gas checks and seals.
Offset Mount
A mounting system that allows an optic or accessory to be positioned off to the side of the firearm’s bore axis, often used to provide an alternate sighting option or to clear other mounted accessories.
Open Bolt
A firing mechanism where the bolt remains open and to the rear when the firearm is ready to fire. Upon pulling the trigger, the bolt moves forward, chambers a round, and fires it. Open bolt designs are common in submachine guns and some light machine guns.
Open Sight
A type of iron sight that consists of a rear notch and a front post or bead, allowing the shooter to align the sights and aim at the target. Open sights are simple, durable, and commonly found on rifles and shotguns.
Open Tip Match
A type of match-grade bullet designed for precision shooting. Open tip match bullets have a small opening at the tip, created during the manufacturing process, to ensure uniform weight and balance. Despite the opening, they are not designed to expand upon impact.
Optics
Devices such as scopes or red dot sights used to enhance target acquisition.
Out-of-Battery
A condition where the firearm’s action is not fully closed or locked, preventing the firearm from firing safely. Firing out-of-battery can cause malfunctions or catastrophic failure.
Over and Under (O/U)
A type of double-barreled shotgun where the barrels are arranged vertically, one above the other. Over and under shotguns are popular for sporting and hunting due to their balance and accuracy.
Over-Bore
A condition in which a cartridge has a relatively large case capacity for the diameter of the bore, often resulting in higher velocities and increased barrel wear. Over-bore cartridges require careful load development and barrel maintenance.

P

Paramilitary Ammunition
Ammunition designed for use by military or paramilitary forces, often characterized by its ruggedness, reliability, and compliance with military specifications.
Paramilitary Firearm
Firearms designed for use by paramilitary forces, which may include police tactical units, security forces, and militias. These firearms often share characteristics with military weapons but are intended for non-military use.
Parkerizing
A method of protecting steel surfaces from corrosion and wear by applying a phosphate coating. Parkerizing provides a durable, matte finish and is commonly used on military firearms.
Parts Kit
A collection of firearm parts that can be assembled into a complete firearm. Parts kits are often sold without the receiver, which is legally considered the firearm under U.S. law.
Percussion Cap
A small, metal cap containing a shock-sensitive explosive compound. Percussion caps are placed on a nipple and struck by the hammer to ignite the powder charge in early firearms, such as caplock muskets and pistols.
Picatinny Rail
A standardized mounting platform used for attaching accessories to firearms.
Pinfire
An early type of cartridge ignition system where a small pin protrudes from the cartridge base. When struck by the hammer, the pin ignites the primer inside the cartridge. Pinfire ammunition was popular in the mid-19th century.
Pistol
A type of handgun designed to be held and fired with one hand. Pistols typically have a chamber that is integral with the barrel and include both semi-automatic and single-shot designs.
Pistol Grip
A handle that allows the shooter to hold and control the firearm more effectively. Pistol grips are commonly found on handguns and some rifles and shotguns.
Plinking
Informal target shooting, often at non-standard targets such as cans, bottles, or reactive targets. Plinking is typically done for fun and practice, using inexpensive ammunition.
Point Blank
The distance at which a firearm can be aimed directly at a target without needing to compensate for bullet drop. Point blank range varies depending on the firearm and ammunition used, generally referring to very close range.
POA (Point of Aim)
The specific point at which a shooter aims their firearm. The point of aim is used as a reference for adjusting sights and aligning with the intended target.
Point of Impact
The location where a bullet or projectile strikes the target. The point of impact can differ from the point of aim due to factors such as bullet drop, wind, and sight alignment.
Ported Chamber
A chamber design that includes small ports or holes to vent gases, reducing recoil and muzzle rise. Ported chambers are often found in competition and high-performance firearms.
Powerhead or Bang Stick
A specialized firearm used underwater to kill large fish or aquatic animals. Powerheads are mounted on spears or poles and are fired by direct contact with the target.
Primer Residue
Residue left behind after a cartridge’s primer is ignited. This residue can accumulate in the firearm’s action and barrel, potentially affecting performance and reliability. Regular cleaning is essential to manage primer residue and ensure optimal firearm function. For more detailed information, read our article Understanding Primer Residue and its Impact on AR-15 Performance.
Propellant
The chemical substance in a cartridge that burns to produce gas, driving the bullet or projectile out of the barrel. Common propellants include smokeless powder and black powder.
Pump-Action
A type of firearm action where the shooter manually cycles the action by moving a forearm piece (pump) backward and forward. Pump-action firearms are commonly found in shotguns and some rifles.

Q

Quick-Detach Mount
A type of mount that allows for rapid attachment and detachment of firearm accessories.

R

Ramrod
A long, straight rod used to push a projectile and powder charge down the barrel of a muzzleloading firearm. Ramrods are essential tools for loading and cleaning such firearms.
Rate of Fire
The number of rounds a firearm can fire in a given period, typically measured in rounds per minute (RPM). Rate of fire can vary between semi-automatic, burst, and fully automatic modes.
Receiver
The part of a firearm that houses the operating parts, typically considered the core of the firearm.
Recoil
The backward movement or kick of a firearm when it is discharged. Recoil is caused by the momentum of the bullet and the expanding gases pushing back against the firearm.
Recoil Operation
A type of firearm action that uses the energy of recoil to cycle the action, eject the spent cartridge, and chamber a new round. Recoil-operated firearms include many semi-automatic pistols and some shotguns.
Red Dot Magnifier
An optical device used in conjunction with a red dot sight to provide magnification, allowing for greater accuracy at longer distances. Red dot magnifiers can be quickly flipped to the side when not in use.
Red Dot Sight
A non-magnifying reflector sight that uses a red LED to project a dot onto a lens, providing a point of aim. Red dot sights are popular for their fast target acquisition and ease of use.
Reflector (Reflex) Sight
An optical sight that uses a partially reflecting lens to project an illuminated reticle, such as a dot or crosshair, onto the shooter’s field of view. Reflex sights are commonly used for rapid target acquisition.
Reversed Bullet
A bullet that is loaded backward in a cartridge case, either intentionally or accidentally. Reversed bullets can cause dangerous pressure spikes and are not recommended for use.
Reload
The process of manually assembling a cartridge by combining a case, primer, powder, and bullet. Reloading allows shooters to customize ammunition and reduce costs.
Revolver
A type of handgun that has a revolving cylinder with multiple chambers, each holding a cartridge. As the hammer is cocked or the trigger is pulled, the cylinder rotates to align a new chamber with the barrel.
Ricochet
The deflection of a bullet or projectile off a surface, causing it to change direction. Ricochets can be dangerous as they can result in unintended impacts.
Rifle
A long-barreled firearm designed for precision shooting, typically fired from the shoulder. Rifles have spiral grooves (rifling) inside the barrel to stabilize the bullet in flight.
Rifle Bedding
The process of fitting the rifle action to the stock to ensure a stable and consistent interface. Proper bedding can improve accuracy by reducing movement and stress on the action during firing.
Rifling
The spiral grooves cut into the bore of a firearm’s barrel that impart a spin to the projectile, stabilizing it in flight and improving accuracy.
Rimfire
A type of cartridge ignition where the primer compound is located in the rim of the cartridge case. Rimfire cartridges, such as the .22 LR, are typically used in small-caliber firearms and are known for their simplicity and cost-effectiveness.
Riot Gun
A type of shotgun designed for crowd control and close-quarters combat, often used by law enforcement and military personnel. Riot guns typically have short barrels and are designed to fire a variety of ammunition types, including less-lethal rounds.
Rolling Block
A type of firearm action where the breechblock rotates around a pin to open and close the breech. Rolling block actions are known for their simplicity and strength and were widely used in 19th-century rifles.
Rotary Cannon
A type of multi-barrel firearm, similar to a Gatling gun, that uses a rotating barrel assembly to achieve high rates of fire. Rotary cannons are typically used in aircraft and military vehicles. Examples include the M61 Vulcan.
Round
A complete unit of ammunition, consisting of a cartridge case, primer, powder, and bullet. The term “round” is often used interchangeably with “cartridge.”
RPM (Rounds Per Minute)
A measurement of the rate of fire of a firearm, indicating the number of rounds it can fire in one minute. RPM is an important factor in evaluating the performance of automatic and semi-automatic weapons.

S

Sabot
A lightweight carrier used to encase a smaller projectile, allowing it to be fired from a larger caliber barrel. The sabot falls away after exiting the barrel, leaving the projectile to continue toward the target.
Safety
A mechanism that prevents the firearm from firing unintentionally.
Sawed-Off Shotgun / Sawn-Off Shotgun / Short-Barreled Shotgun (SBS)
A shotgun with a barrel length shorter than the legal minimum, typically resulting in a compact, concealable weapon. Short-barreled shotguns are regulated and restricted in many jurisdictions.
Scope
An optical sighting device mounted on a firearm to aid in accurate aiming, typically featuring magnification to help the shooter see targets at a distance.
Selective Fire
A feature on some firearms that allows the shooter to select between different firing modes, such as semi-automatic, burst, or fully automatic fire.
Selector
A switch or lever on a selective-fire firearm that allows the shooter to choose the desired firing mode.
Semi-Automatic
A type of firearm that fires one round with each pull of the trigger, automatically cycling the action to eject the spent cartridge and chamber a new one.
Semi-Automatic Pistol
A handgun that fires one round per trigger pull and uses the energy from the fired cartridge to cycle the action, eject the spent case, and load a new round.
Semi-Wadcutter (SWC)
A type of bullet with a flat nose and a sharp shoulder, designed to cut clean holes in targets for easy scoring. SWC bullets are commonly used in target shooting and self-defense.
Shells
A term commonly used to refer to shotgun ammunition, consisting of a case filled with shot or a slug, powder, and a primer. The term can also refer to the casing of any type of ammunition.
Shooting Range
A facility designed for the safe practice of shooting firearms. Shooting ranges can be indoor or outdoor and are often equipped with targets, backstops, and safety features.
Shooting Sticks
Portable supports used by hunters to stabilize their firearms while aiming and shooting. Shooting sticks can be monopods, bipods, or tripods.
Short-Barreled Rifle (SBR)
A rifle with a barrel length shorter than the legal minimum, typically less than 16 inches in the U.S. Short-barreled rifles are regulated and restricted in many jurisdictions.
Shotgun
A firearm designed to shoot a spread of shot or a single slug, typically used for hunting and sport shooting. Shotguns come in various action types, including pump action, semi-automatic, and break action.
Side by Side (SxS)
A type of double-barreled shotgun where the barrels are arranged horizontally, side by side. Side by side shotguns are popular for hunting and sport shooting.
Silencer
A device attached to the muzzle of a firearm to reduce the noise and muzzle flash generated by firing. Also known as a suppressor.
Single-Action
A type of firearm action where the hammer must be manually cocked before the trigger can be pulled to fire a shot. Single-action mechanisms are commonly found in revolvers and some semi-automatic pistols.
Single-Shot
A firearm that holds only one round of ammunition at a time and must be manually reloaded after each shot. Single-shot firearms are known for their simplicity and reliability.
Slamfire
An unintended discharge that occurs when the bolt or slide of a firearm closes and the firing pin strikes the primer without the trigger being pulled. Slamfires can be caused by mechanical issues or improper handling.
Sleeving
A process of inserting a new barrel liner or sleeve into a worn or damaged barrel to restore its accuracy and functionality.
Slide Bite or Snake Bite
An injury caused when the slide of a semi-automatic pistol pinches or cuts the shooter’s hand, usually during recoil.
Sling
A strap attached to a firearm to aid in carrying and stabilize the firearm while shooting. Slings come in various styles, including single-point, two-point, and three-point configurations.
Smokeless Powder
A type of modern gunpowder that produces minimal smoke when burned, offering a cleaner and more efficient propellant compared to traditional black powder.
Snubnosed Revolver
A compact revolver with a short barrel, typically 3 inches or less, designed for concealed carry and close-quarters defense.
Speedloader
A device used to quickly load multiple rounds into a revolver’s cylinder or a magazine, speeding up the reloading process.
Spitzer Bullet
A type of bullet with a pointed, aerodynamic shape designed to reduce air resistance and improve ballistic performance. Spitzer bullets are commonly used in rifle cartridges.
Sporterizing, Sporterisation, or Sporterization
The process of modifying a military or surplus firearm to make it more suitable for sporting use, often involving changes to the stock, barrel, and sights.
Squib Load (also known as Squib Round, Pop and No Kick, or just Squib)
A malfunction where a cartridge does not develop enough pressure to propel the bullet out of the barrel, often resulting in a lodged bullet. Squib loads are dangerous because firing another round can cause a catastrophic failure.
Stock
The part of a firearm that provides structural support and is held against the shooter’s shoulder or hand. Stocks are made from various materials, including wood, plastic, and composite materials.
Stopping Power
The ability of a firearm or cartridge to incapacitate a target with a single shot. Stopping power is influenced by factors such as bullet caliber, velocity, and shot placement.
Stripper Clip
A device used to hold multiple rounds of ammunition together for rapid loading into a firearm’s internal magazine. Stripper clips are commonly used with bolt-action rifles.
Submachine Gun
A compact, fully automatic firearm that fires pistol-caliber cartridges. Submachine guns are designed for close-quarters combat and are commonly used by military and law enforcement.
Suppressor
A device attached to or integrated with the barrel of a firearm to reduce the noise and muzzle flash generated by firing.
Swage
The process of shaping metal under pressure, often used in bullet manufacturing to create precise shapes and sizes. Swaging can also refer to resizing cartridge cases.
Swaged Bullet
A bullet formed by compressing lead or another metal in a die to achieve a specific shape and size, resulting in a consistent and accurate projectile.
Swaged Choke
A type of shotgun choke that is formed by swaging, or pressing, the barrel to constrict the bore at the muzzle end, controlling the spread of the shot.
Swaged Rifling
A method of forming rifling in a barrel by pressing or swaging the rifling pattern into the bore, resulting in smooth and precise grooves that stabilize the bullet in flight.

T

Tapering
The gradual reduction in diameter of a cartridge case or barrel. Tapering helps with feeding and extraction in firearms and can also influence the internal ballistics of a cartridge.
Taylor KO Factor
A formula developed by John “Pondoro” Taylor to estimate the effectiveness of hunting cartridges for big game. The formula considers bullet diameter, weight, and velocity to provide a comparative measure of stopping power.
Telescoping Stock or Collapsing Stock
A type of adjustable stock that can be shortened or lengthened to fit the shooter’s preference. Telescoping stocks are commonly found on modern rifles and shotguns, providing versatility and ease of transport.
Terminal Ballistics
The study of the behavior and effects of a projectile when it hits its target. Terminal ballistics examines factors such as penetration, expansion, and wound channel to assess the effectiveness of different ammunition types.
Throat Erosion (Firearms)
Wear and damage to the throat or leade of a firearm’s barrel, typically caused by the high-pressure and high-temperature gases produced when firing. Throat erosion can affect accuracy and is a common issue in high-volume shooting.
Trajectory
The path that a projectile follows after it is fired from a firearm. The trajectory is influenced by factors such as gravity, air resistance, and the projectile’s velocity and spin.
Trigger
The mechanism that initiates the firing of a firearm when pulled or pressed by the shooter. The trigger releases the hammer or striker, causing the firearm to discharge.
Trigger Pull Weight
The amount of force required to pull the trigger and discharge the firearm.
Trunnion
A pivot point or support used in firearms to allow movement and alignment of components. In many rifles and machine guns, trunnions provide a mounting point for the barrel and other key parts.
Turn Bolt
A type of bolt-action mechanism where the shooter rotates the bolt handle to unlock the bolt, cycles the action to load and eject cartridges, and then locks the bolt back into place. Turn bolt actions are known for their strength and reliability.

U

Upset Forging
A metalworking process in which a metal workpiece is compressed and deformed to increase its diameter. Upset forging is commonly used in the manufacturing of firearm components to enhance strength and durability.
Underlug
A projection on the underside of a firearm barrel, typically found on revolvers, that provides additional support and attachment points for components such as the ejector rod or cylinder crane.
Underwater Firearm
A firearm specifically designed or modified to be used underwater. These firearms often use specialized ammunition to function reliably in submerged conditions and are typically used by military divers and special operations forces.
Upper Receiver
The top part of the receiver that houses the barrel, bolt carrier group, and other critical components. Shop Upper Receivers

V

Varmint Rifle
A type of rifle specifically designed for hunting small, pest animals such as rodents and other small game. Varmint rifles are typically characterized by their high accuracy, flat trajectory, and use of lightweight, high-velocity cartridges.
Velocity
The speed at which a projectile travels after being fired from a firearm. Velocity is usually measured in feet per second (fps) or meters per second (m/s) and is a key factor in determining the ballistic performance and impact energy of a bullet.
Vertical Foregrip
A grip attached to the front of the firearm to improve control and stability.

W

Wadcutter
A type of bullet with a flat-front design, typically used in target shooting. Wadcutters create clean, round holes in paper targets, making them easy to score.
WCF (Winchester Center Fire)
A designation used by Winchester for a series of centerfire rifle cartridges developed in the late 19th and early 20th centuries. Examples include the .30-30 WCF and .32-20 WCF.
Weaver Rail
A mounting system similar to the Picatinny rail but with slightly different dimensions and spacing.
Wheellock
An early firearm ignition system that uses a rotating, spring-loaded wheel to generate sparks and ignite the priming powder. Wheellocks were used in the 16th and 17th centuries before being replaced by flintlock mechanisms.
Wildcat Cartridge or Wildcat
A custom cartridge created by modifying an existing commercial cartridge to achieve specific performance characteristics. Wildcat cartridges are often developed by enthusiasts and can offer improved velocity, accuracy, or terminal performance.
Windage
The horizontal adjustment of a firearm’s sights to compensate for the effect of wind on the bullet’s trajectory. Windage adjustments are essential for accurate long-range shooting.

X

X-Ring
The center ring on a target, often used as an aim point in competitive shooting.

Y

Yaw
The deviation of a bullet from its intended flight path due to instability.

Z

Zero-in or Zeroing
The process of adjusting sights or an optic to ensure the point of aim matches the point of impact.
Zero Stop
A feature in some rifle scopes that allows the shooter to quickly return to the zero setting of the elevation turret after making adjustments for distance. This ensures that the shooter can easily revert to the original zero without counting clicks or making further adjustments.

Conclusion

We hope this Comprehensive Firearms Glossary has been a valuable resource in enhancing your understanding of essential firearm terms and concepts. Whether you're a beginner or an experienced enthusiast, having a solid grasp of these terms is crucial for safe and effective firearm use.

Feel free to explore our firearms blog for more in-depth articles, including firearm guides, and firearm reviews that dive deeper into specific topics covered in this glossary. If you have any questions or need further clarification on any terms, don't hesitate to reach out to us or join our community discussions.

Happy shooting and stay safe!

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Elyssa McGregor

Elyssa is the Information Technology Manager at KAK Industry. She blends her tech expertise with a passion for the firearm industry. She thrives on crafting innovative ideas and conducting research for engaging blog posts and marketing materials. Elyssa's unique approach reflects her dedication to both technology and the firearms community.

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