Gun Terms Glossary

In bullet terms, ACP stands for Automatic Colt Pistol, a designation used for several cartridges designed by John Browning for Colt semi-automatic pistols. Examples include .45 ACP and .380 ACP, with each cartridge offering specific ballistic properties suited for use in handguns.

The action of a firearm refers to its functional components that directly affect the cartrdige once inside the weapon; The parts that load, fire, and eject a cartridge. This term can also refer to the method of operation of a certain firearm - I.E. Bolt-action, lever-action, auto-loading, etc.

The "AK" in AK-47 stands for Avtomat Kalashnikova, named after its designer, Mikhail Kalashnikov. It translates to "Kalashnikov's Automatic Rifle," with the "47" referring to the year 1947, when the rifle was first developed.

The successor to the AK-47, the AKM or Avtomat Kalashnikova Moderna (AK Modernized) introduced stamped components for the receiver's construction. This is the most common version of the AK.

Ambidextrous refers to the ability to use both the right and left hands equally well. In the context of tools or firearms, ambidextrous designs allow for easy use by both right- and left-handed individuals, providing flexibility and comfort for all users.

A catch-all term for cartridges or projectiles intended to be launched from a weapon system.

Anodized refers to a process in which a metal, typically aluminum, is coated with a protective oxide layer through an electrochemical process. This enhances the metal's durability, corrosion resistance, and appearance, while often allowing for color customization.

Anti-walk pins are components designed to prevent the trigger and hammer pins in firearms, like the AR-15, from shifting out of place during use. They provide added security by locking the pins in position, ensuring consistent performance and reliability under heavy use or recoil.

An AR firearm is a lightweight, gas-operated, magazine-fed rifle originally developed for military use, with "AR" standing for ArmaLite Rifle, the company that designed it. Known for its modularity and customization options, the AR platform is popular in both military and civilian applications, including the AR-15 and AR-10 models.

The AR-10 is a semi-automatic, gas-operated rifle chambered in larger calibers like .308 Winchester, designed for long-range precision and increased stopping power. As the predecessor to the AR-15, the AR-10 offers a robust platform suited for hunting, target shooting, and military applications.

The AR-15 is a lightweight, semi-automatic rifle known for its versatility and modular design, chambered typically in .223 Remington or 5.56 NATO. Popular for civilian use in hunting, sport shooting, and home defense, it is highly customizable with a wide range of aftermarket parts and accessories.

(Bureau of Alcohol, Tobacco, Firearms and Explosives) is a federal agency responsible for regulating firearms, enforcing gun laws, and overseeing the sale and ownership of NFA-regulated items in the United States.

In the world of firearms, auto-loading guns are those which chamber or "load" the next round after firing automatically.

In modern parlance, automatic firearms are those that are functionally machineguns. Historically, the term automatic referred to auto-loading firearms like semi-automatic handguns.

The ballistic coefficient (BC) is a measure of a projectile's ability to overcome air resistance in flight, directly influencing its speed, trajectory, and retained energy. A higher BC indicates better aerodynamic efficiency, allowing the bullet to maintain velocity and accuracy over longer distances.

Ballistics is the study of the motion, behavior, and effects of projectiles, such as bullets or shells, in flight. It encompasses the analysis of the forces acting on a projectile from the moment it is fired to its impact, including internal, external, and terminal ballistics.

A banana magazine is a curved, detachable magazine typically used in rifles, such as AK-47s, designed to hold and feed ammunition. Its distinctive curved shape allows for a higher capacity while facilitating smoother feeding of rounds into the firearm.

A barrel is the cylindrical component of a firearm through which a bullet is fired, featuring spiral grooves known as rifling that impart spin to stabilize the projectile. The length, material, and rifling of the barrel directly affect the rifle's accuracy, velocity, and range.

A barrel band is a metal clamp or ring that secures the barrel of a rifle to the stock, often found in older or military-style firearms. It helps maintain the structural integrity of the rifle by keeping the barrel and stock aligned, contributing to the firearm's overall stability and accuracy.

A barrel nut is a fastening component used to secure the barrel of a firearm, particularly in AR-15 rifles, to the upper receiver. It plays a crucial role in maintaining the stability of the barrel and providing a mounting point for handguards or other accessories.

A shotgun bead is a small, spherical sight positioned at the front of a shotgun's barrel, serving as a visual aid for aiming. It helps the shooter quickly align the shotgun with the target, making it ideal for fast-moving shots in activities like hunting or trap shooting.

Billet refers to a solid block of metal, typically aluminum or steel, that is machined or milled into a specific component, such as a firearm receiver. Billet construction is known for its strength and precision, as the part is carved from a single piece of metal rather than being forged or cast.

A binary trigger is a specialized firearm trigger that fires a round on both the pull and release of the trigger, effectively doubling the rate of fire compared to standard triggers. This allows for faster shooting without converting the firearm into a fully automatic weapon, making it popular for both recreational shooting and certain tactical scenarios.

Black powder is a traditional firearm propellant composed of potassium nitrate, charcoal, and sulfur, used historically in early firearms and cannons. It produces significant smoke and residue upon ignition, making it less efficient and dirtier compared to modern smokeless powder.

Blowback in firearms refers to a simple operating mechanism where the force from the expanding gases of a fired cartridge pushes the slide or bolt backward, cycling the action. This system is commonly used in semi-automatic pistols and submachine guns, relying on the rearward force to eject the spent casing and chamber a new round.

Bluing is a metal treatment process used on firearms to provide a thin protective layer that resists rust and corrosion while giving the metal a dark blue or black finish. It works by inducing a controlled oxidation process on the steel surface, enhancing durability and offering a classic aesthetic commonly associated with firearms.

A boat tail refers to a bullet design where the rear of the bullet tapers to a point, resembling the shape of a boat's hull. This aerodynamic shape reduces drag during flight, improving the bullet’s accuracy and retaining velocity over long distances, making it popular for long-range shooting and precision applications.

The bolt in firearms is a mechanical component that moves back and forth to load, chamber, and eject cartridges in bolt-action or semi-automatic rifles. It plays a crucial role in the firing process by locking the cartridge in place and ensuring proper ignition and cycling of the firearm.

A bolt-action rifle is a firearm where the shooter manually operates a bolt to chamber a round, eject the spent casing, and reset the firing mechanism after each shot. Known for its reliability and precision, this type of rifle is widely used in hunting, long-range shooting, and sniper applications.

A bolt carrier group (BCG) is a critical assembly in a firearm, particularly in AR-style rifles, responsible for cycling the action, chambering rounds, and ejecting spent casings. It includes components such as the bolt, firing pin, and extractor, working together to ensure proper functioning during semi-automatic or fully automatic fire.

A bolt hold open is a mechanism in a semi-automatic firearm that locks the bolt in the rear position after the last round is fired. This feature allows the shooter to quickly reload and know when the magazine is empty without having to manually check the chamber.

The bore in firearms is the interior of the barrel through which the bullet or projectile travels when the gun is fired. It can be smooth or rifled, with rifling consisting of spiral grooves that impart spin to the projectile for improved accuracy and stability.

A bore snake is a flexible, pull-through cleaning tool designed to quickly and efficiently clean the inside of a firearm's barrel. It features integrated brushes and cloth material that removes residue, fouling, and debris, simplifying the cleaning process without the need for traditional rods and patches.

A boresight is a tool or method used to align a firearm's barrel (bore) with its sights or optic before actual live firing, ensuring the point of aim is close to the point of impact. This process helps reduce the amount of live ammunition needed to zero the firearm, making sighting in faster and more efficient.

The outer shell of a cartridge, typically made from brass, that houses the primer, powder, and bullet in a firearm. Known for its durability and corrosion resistance, brass casings are widely used because they can be reloaded and reused multiple times, making them popular among shooters and reloaders.

A break-action firearm is one where the barrel is hinged and can be "broken" open to expose the chamber, allowing for manual loading and unloading of ammunition. Common in shotguns and some rifles and pistols, this simple mechanism is prized for its reliability and ease of use in single or double-barrel configurations.

The breech is the rear part of a firearm’s barrel where the ammunition is loaded and fired from, as opposed to the muzzle at the front. In modern firearms, breech mechanisms are designed to securely close and contain the pressure from the fired cartridge, ensuring safe and efficient operation.

Buckshot refers to a type of shotgun ammunition that contains multiple large pellets, typically used for hunting larger game like deer or for self-defense. When fired, the pellets spread out in a pattern, increasing the chances of hitting the target at close to medium ranges.

A buffer in firearms is a component typically found in semi-automatic and automatic rifles, such as the AR-15, that helps absorb recoil and control the cycling of the bolt carrier group. It works in conjunction with the buffer spring to reduce felt recoil and ensure smooth operation of the firearm by managing the rearward motion after firing.

A buffer tube, also known as a receiver extension, is a cylindrical housing in AR-style rifles that contains the buffer and buffer spring, essential for the firearm's recoil management and cycling system. It also provides a mounting point for the rifle's stock and plays a key role in absorbing and controlling the rearward motion of the bolt carrier group after firing.

A bug out gun is a firearm specifically chosen for emergency situations where quick evacuation, survival, or self-defense is necessary. It is typically reliable, lightweight, and versatile, intended for use in unpredictable or dangerous scenarios during a "bug out" or escape from a disaster.

Bulk ammo refers to large quantities of ammunition sold together, often packaged in boxes, cans, or loose rounds for cost-effective purchasing. It is popular among shooters for range practice, training, or stockpiling, offering lower prices per round compared to smaller packaging.

A bullet is the projectile fired from a firearm and is a component of an ammunition cartridge. Traditionally bullets are made of lead, but can be built from any suitably dense or durable material.

A bullet base is the bottom portion of a bullet, opposite the tip, which is the last part to exit the barrel when fired. The design of the bullet base, whether flat, boat-tail, or hollow, affects the bullet's aerodynamics, stability, and overall performance in flight.

Bullet weight refers to the mass of a bullet, typically measured in grains, which affects its velocity, trajectory, and impact on the target. Heavier bullets tend to retain energy over longer distances, while lighter bullets typically travel faster but may lose energy more quickly.

The butt of a firearm is the rear part of the stock that rests against the shooter’s shoulder when firing. It provides stability, helps absorb recoil, and is often made from wood, polymer, or metal, depending on the firearm's design and purpose.

A butt plate is a protective cover attached to the rear end of a rifle or shotgun stock, providing a surface for the shooter to rest against their shoulder. It helps absorb recoil and can be made of various materials like rubber, metal, or plastic, enhancing comfort and stability during firing.

Caliber refers to the internal diameter of a firearm's barrel or the diameter of the bullet it is designed to fire, typically measured in inches or millimeters. It determines the size, power, and compatibility of ammunition, making it a critical factor in a firearm's performance and intended use.

A precision measuring tool used to gauge distances between objects. Especially useful for measuring small distances like barrel inner diameters.

Can is a slang term for sound suppressor based on the can-like appearance of most suppressors.

A cannelure is a groove or series of grooves around the bullet or case of a cartridge, often used to crimp the bullet securely in place or reduce friction when fired. It can also help control bullet expansion or fragmentation upon impact, enhancing performance in specific applications like hunting or defense.

In firearms, cant refers to the tilt or angle of the firearm away from being perfectly vertical when aiming or shooting. Properly managing cant is important for accuracy, particularly in long-range shooting, as an incorrect angle can cause the bullet's trajectory to deviate from the intended target.

In firearms, a cantilever refers to a mounting system where an accessory, such as a scope or optic, is supported by a bracket that extends forward from its attachment point. This design allows for better weight distribution, increased flexibility in positioning the optic, and compatibility with firearms lacking traditional rail space.

A carbine is a lightweight, compact rifle with a shorter barrel than a standard rifle, designed for improved handling and maneuverability, especially in close-quarters situations. Carbines are often chambered in the same calibers as full-sized rifles, making them popular for tactical use, home defense, and some hunting applications.

Carbine length refers to a shorter barrel length typically around 16 inches, often used in compact rifles for increased maneuverability and reduced weight. In the AR-15 platform, it also describes a gas system configuration where the gas port is positioned closer to the chamber for faster cycling, making it ideal for tactical and close-quarters applications.

Case trimming is the process of shortening and reshaping the brass casing of a cartridge to a uniform length after it has been fired and resized. This ensures consistent chambering, optimal performance, and safety when reloading ammunition, as repeated firings can cause the brass to stretch.

A casing in firearms is the cylindrical shell that holds the bullet, gunpowder, and primer together, forming a complete cartridge. After firing, the casing is typically ejected from the firearm, leaving the projectile to travel downrange, while the casing may be reloaded or discarded depending on the type of ammunition.

Centerfire refers to a type of ammunition in which the primer is located in the center of the cartridge base, allowing the firing pin to strike and ignite the primer for firing. This design, used in most modern rifle and handgun cartridges, is more reliable and capable of handling higher pressures than rimfire ammunition.

The chamber in firearms is the part of the barrel or frame where a cartridge is loaded and held in place before firing. It is precisely machined to match the dimensions of the specific cartridge being used, ensuring proper fit, alignment, and safe firing.

Chamfer refers to the process of cutting or beveling the sharp edges of a material, typically at a 45-degree angle, to create a smoother transition between surfaces. In firearms, chamfering is often applied to the edges of a barrel, chamber, or cylinder to ease reloading and reduce wear on ammunition.

A charging handle is a manual device on a firearm, often found in rifles like the AR-15, used to pull the bolt carrier group back, chamber a round, or clear the chamber. It plays a critical role in loading the firearm, resetting it after firing, or handling malfunctions.

A pattern of small, raised ridges or grooves carved into the surface of a firearm's grip, stock, or forearm. This textured design enhances grip and control, providing better handling and preventing slippage during shooting, especially in adverse conditions.

A constriction at the end of a shotgun barrel designed to control the spread of the shot pattern as it exits the barrel. Different choke types, such as full, modified, or improved cylinder, allow shooters to adjust the tightness of the shot spread for various ranges and shooting applications.

In the world of guns, a firearm is considered "clear" when its action is locked open, safety selector is engaged, magazine emptied and removed, its chamber empty (no cartridge) and there is no ammunition in the direct vicinity of it. This designates the firearm as safe to handle.

Stands for "Chief Law Enforcement Officer". A CLEO must be notified when you purchase a suppressor or silencer.

Often incorrectly used interchangably with the term magazine, a clip holds ammunition rounds together to be loaded into a firearm's magazine or cylinder. It differs from a magazine in that it is not spring-loaded.

CLP stands for Cleaner, Lubricant, and Protectant, a multi-purpose solution used for firearm maintenance. It cleans away fouling and debris, lubricates moving parts to ensure smooth operation, and provides a protective coating to prevent rust and corrosion.

Co-witness refers to the alignment of a firearm's iron sights with an attached optic, such as a red dot sight, allowing both sighting systems to be used simultaneously. This setup provides redundancy, ensuring that if the optic fails, the shooter can still use the iron sights without adjusting their shooting stance or sight picture.

In the world of firearms, the term cock refers to the action of pulling back the hammer to its locked rearward position where it is ready (or primted) to be dropped on a firing pin to detonate a cartridige.

Combloc, short for Communist Bloc, refers to the group of Eastern European and Soviet-aligned countries during the Cold War era that produced standardized military equipment and firearms, such as the AK-47 and SKS rifles. Firearms and ammunition from Combloc countries are often characterized by their rugged design, reliability, and use of common calibers like 7.62x39mm.

A compensator is a muzzle device attached to the end of a firearm's barrel designed to reduce muzzle rise by redirecting gas upward when a shot is fired. This allows the shooter to maintain better control and faster follow-up shots by minimizing the upward movement caused by recoil.

In the world of firearms, Concealed Carry is the act of lawfully carrying a firearm on one's person hidden from plain sight. It can also refer to firearms or tools designed specifically to be easily concealed on an individual's body.

A concentricity gauge is a precision tool used to measure the uniformity of a cartridge or bullet's alignment, specifically checking if the bullet is seated evenly within the case. It ensures that the ammunition is balanced and aligned properly, which can improve accuracy and consistency, particularly in long-range shooting.

Is the rotating component of a revolver that holds multiple chambers for cartridges. As the cylinder rotates, each chamber aligns with the barrel and firing mechanism, allowing successive shots to be fired without reloading.

Deburring is the process of removing sharp edges, rough spots, or excess material (burrs) left behind on metal parts after machining or cutting. In firearms manufacturing, deburring is essential to ensure smooth operation, improve the fit of components, and enhance safety by eliminating imperfections that could affect performance.

Decapping is the process of removing the spent primer from a used cartridge case during the reloading process. This step is essential before inserting a new primer to prepare the case for reloading and firing again.

A decapping die is a reloading tool designed to remove spent primers from cartridge cases by pushing them out through the primer pocket. It is used in the initial stage of the reloading process, ensuring the case is ready to receive a new primer for subsequent reloading.

A decocking lever is a firearm mechanism that safely lowers the hammer or firing pin from a cocked position without firing the weapon. It allows the shooter to disengage the firing mechanism, typically in double-action pistols, reducing the chance of an accidental discharge.

A suppressor attachment method screws directly onto a firearm’s threaded barrel, providing a secure and stable fit for improved sound suppression and accuracy.

A disconnector is a small device which breaks the mechanical connection between the trigger and the hammer/striker. When the trigger is pulled, the disconnector releases the hammer to the sear preventing the firearm from firing until the trigger is pulled again.

An AK-47 "dong" refers to a distinctive wooden foregrip attached to some AK-47 rifles, characterized by its curved, downward extension resembling a "dong" shape. This grip provides better control and stability when firing, particularly during rapid fire or in full-auto mode, and is commonly seen on certain Eastern European or Vietnamese AK variants.

A double-action firearm is one in which pulling the trigger performs two functions: cocking the hammer and releasing it to fire the round, all in a single trigger pull. This mechanism is commonly found in revolvers and some semi-automatic pistols, allowing for faster firing without manually cocking the hammer between shots.

A double feed is a firearm malfunction where two cartridges attempt to enter the chamber simultaneously, causing a jam. This often occurs due to issues with the magazine or extractor, and it prevents the firearm from cycling properly until cleared.

Refers to a magazine design where the ammunition is staggered in two vertical columns, allowing for a higher capacity compared to single-stack magazines. This design is commonly used in semi-automatic pistols and some rifles, enabling the firearm to hold more rounds without significantly increasing the magazine's length.

A double tap in firearms refers to the technique of quickly firing two consecutive shots at a target with minimal time between them, typically to increase the chances of stopping a threat. This method is often practiced in defensive shooting and competition to improve accuracy and speed under pressure.

Doubling in firearms refers to the unintentional discharge of two rounds with a single pull of the trigger, often due to a malfunction or mechanical issue. This can occur in semi-automatic firearms when the trigger mechanism or sear fails to reset properly between shots, leading to a safety concern.

A type of machined, angled groove or notch used to securely mount components such as sights or scope bases onto a firearm. The design allows for a tight, friction-based fit, ensuring that the attached part remains stable under recoil and use.

Dram equivalent is a measurement used in shotgun ammunition to represent the power or velocity of modern smokeless powder compared to the older black powder loads, originally measured in drams. It provides shooters with a way to gauge the relative performance of the ammunition, even though modern shells use different propellants.

Drop refers to how far a round falls vertically from gravity while in flight. While gravity may be constant, velocity is not. Rounds with higher velocity suffer from less drop than slower ones and thus require less vertical adjustment to hit an intended target.

A drum magazine is a cylindrical-shaped firearm magazine that stores rounds in a spiral around the center, facing the barrel. Drum magazines are used to feed cartridges to light machine guns or submachine guns. They are considered a better feed than belt systems for flexible guns.

Dry firing is the act of pulling the trigger on an unloaded firearm, causing the firing mechanism to function without discharging a live round. It is often used for training and practice to improve trigger control, but can potentially cause wear on certain firearms, particularly those with rimfire designs.

Refers to a cartridge that fails to fire when the primer is struck, often due to a defective primer or improper storage. This malfunction requires the shooter to safely clear the misfired round from the chamber before continuing to use the firearm.

Is a non-functional replica of a real cartridge, typically used for training, practice, or testing firearm mechanics without the risk of firing. It lacks gunpowder and an active primer, making it safe for handling, loading drills, and malfunction clearing exercises.

Is a protective component, often found on rifles like the AR-15, designed to shield the ejection port from dirt, dust, and debris when the firearm is not in use. It automatically opens when the firearm is fired, ensuring smooth ejection of spent cartridges while keeping the internal components clean during operation.

Refers to the maximum distance at which a firearm or ammunition can accurately and reliably hit a target while maintaining sufficient power to achieve the intended result. This range varies depending on the firearm, ammunition type, and environmental factors, such as wind and elevation.

The process of expelling a spent cartridge casing from the chamber after a round is fired, clearing the way for the next round to be chambered. This action is typically performed by the firearm's ejector mechanism and is crucial for the proper cycling of semi-automatic and automatic firearms.

Ejection port loading is the process of manually inserting a cartridge directly into the chamber of a firearm through the ejection port, bypassing the magazine. This method is often used in semi-automatic firearms when a quick reload is needed, allowing the shooter to chamber a round without fully loading the magazine.

Is a component that grips the rim of a spent cartridge and pulls it out of the chamber after firing. It works in conjunction with the ejector to remove the spent casing, ensuring proper cycling and preparing the firearm for the next round.

Refers to the maximum distance a bullet can travel under ideal conditions, beyond which accuracy, energy, and control are severely diminished. It is typically much farther than the effective range and varies depending on factors like the firearm, ammunition, and environmental conditions.

The distance between a shooter's eye and the eyepiece of an optic, such as a scope, at which a full, clear image is visible. Proper eye relief is crucial for comfort and safety, ensuring that the shooter can maintain a clear sight picture without risking injury from recoil.

A fire control group (FCG) is the collection of internal components in a firearm, typically including the trigger, hammer, and sear, that work together to initiate the firing sequence. These parts control the function of the firearm, determining whether it operates in semi-automatic, burst, or fully automatic modes, depending on the design.

A small, rod-like component that strikes the primer of a cartridge when the trigger is pulled, igniting the gunpowder and firing the round. It plays a critical role in the firing mechanism, converting the mechanical action of the trigger into the energy needed to discharge the bullet.

Flat Dark Earth (FDE) is a specific color finish, often a muted brown or tan, used on firearms and tactical gear to blend in with desert or arid environments. This color is popular for military and civilian use due to its camouflage properties and its non-reflective, matte appearance.

A flat trigger is simply a trigger whose face or forward surface that the index finger applies pressure to, is flat or perpendicular to the receiver.

A floor plate is the bottom portion of a magazine that retains the magazine spring and follower.

A follower is the portion of a magazine that rests on the magazine spring and directly interfaces with ammunition loaded into the magazine. The follower ensures positive, consistant spring tension is applied to rounds in a magazine to facilitate reliable feeding to the action.

A rifle foregrip is an accessory attached to the underside of a rifle's handguard, allowing the shooter to hold the firearm more securely and comfortably. It provides better control and stability, especially during rapid or sustained fire, improving overall handling and accuracy.

A forend, also known as a forearm or handguard, is the part of a firearm located beneath the barrel that provides a gripping surface for the shooter’s support hand. It helps protect the shooter from the heat of the barrel during firing and may feature rails or mounting points for accessories like bipods, lights, or grips.

The forward assist is a a small button on a firearm that allows a shooter to manually push a bolt forward into the locked position. The most common example is the found on the side of an AR-15/M-16 receiver that was developed in the 1960's in response to reliability issues with early M-16 rifles in the Vietnam War.

Fouling refers to the buildup of residue, such as carbon, lead, copper, or powder, inside a firearm's barrel and action as a result of firing rounds. Over time, this accumulation can reduce the firearm's accuracy, reliability, and performance, necessitating regular cleaning to maintain optimal function.

Frangible ammunition is designed to break apart upon impact with a hard surface, reducing the risk of ricochets or over-penetration. It is often used in training or close-quarter environments for safety purposes, as the bullet disintegrates into smaller, less harmful fragments.

A full metal jacket (FMJ) bullet has a soft core, usually made of lead, encased in a harder metal shell, typically copper. This design helps the bullet maintain its shape upon impact, improving penetration and reducing barrel fouling compared to unjacketed bullets.

The buttstock, forearm (handguard), or pistol grip of a firearm.

The Garand was the first semi-automatic firearm adopted by the US Military. Chambered in .30-06, it is renown for its power and reliability.

Controls the gas flow from the barrel to cycle the action in a direct impingement AR-15, affecting recoil, reliability, and compatibility with suppressors or specific ammo.

Small hole in the barrel of an AR-15 that directs gas into the gas system, enabling the cycling of the action for reliable semi-automatic or automatic fire.

A critical component in a direct impingement AR-15, channeling gas from the gas block to the bolt carrier group to cycle the action efficiently.

Gauge is a measurement used to describe the bore size of a shotgun, based on the number of lead balls of a specific diameter that equals one pound. For example, a 12-gauge shotgun means that 12 lead balls, each fitting the bore, would weigh one pound, with smaller numbers indicating larger bores.

The weight of a bullet, measured in grains (gr), which affects velocity, recoil, and performance for different shooting applications.

Refers to the pattern of bullet impacts on a target, indicating accuracy and consistency based on factors like shooter skill, firearm precision, and ammunition quality.

Gunpowder, in modern parlance, refers to smokeless powder or powdered nitrocellulose with additives to reduce flash and increase stability. This powder rapidly oxidises when ignited by a primer, and the expanding hot gases propel a bullet down a barrel and toward a target.

Gunsmithing is the craft and practice of repairing, modifying, customizing, and maintaining firearms to ensure their proper function, safety, and performance. Gunsmiths are skilled professionals who perform tasks such as barrel threading, trigger adjustments, stock refinishing, and creating custom builds to meet the needs of firearm owners.

The hammer is the metal part that strikes the firing pin or percussion cap to ignite the propellant and fire the bullet on a firearm.

Hammerless firearms are those with a concealed hammer. This term is normally reserved for revolvers designed for concealed carry where a protruding hammer can snag on clothing when drawing from a concealed holster.

A handguard is a protective component on a firearm, typically surrounding the barrel, that provides a safe gripping surface for the shooter’s support hand. It shields the user from barrel heat during firing and often features mounting points or rails for accessories such as optics, lights, grips, and bipods.

Headspacing refers to the precise distance between a firearm's breech face and a cartridge's shoulder or base when it is fully chambered. Proper headspacing is critical for safe and reliable operation, as incorrect spacing can lead to malfunctions, misfires, or even dangerous pressure issues during firing.

Hollow point ammo features bullets with a hollowed-out tip designed to expand on impact, delivering maximum stopping power and controlled penetration for self-defense and hunting applications.

A sound suppression system permanently built into a firearm’s barrel, offering enhanced noise reduction, improved balance, and a streamlined design compared to detachable suppressors.

The term iron sights refers to analog aiming devices on a firearm. Traditionally constructed from metal, some modern firearms like the Glock actually have iron sights made of poymer.

The isosceles stance is a shooting technique where the shooter's arms and chest form an isosceles triangle

Inside the waistband (IWB) refers to a holster style that is worn inside the waistband of a person's pants, providing better concealment of the firearm. This method of carry is favored for concealed carry, as it keeps the gun closer to the body and less visible under clothing.

A jacketed hollow point (JHP) bullet features a hollowed-out tip and is covered by a metal jacket, designed to expand upon impact. This expansion increases stopping power while reducing the risk of over-penetration, making it ideal for self-defense and hunting applications.

A jacketed soft point (JSP) bullet has a soft lead tip exposed at the nose, while the rest of the bullet is encased in a harder metal jacket. This design allows for controlled expansion upon impact, offering a balance between deep penetration and effective stopping power.

A lightweight, modular rail system for firearms that allows users to easily attach accessories like grips, lights, and bipods using a keyhole-shaped slot design for a secure and customizable setup.

A compact, short-barreled variant of the AK-series rifles, commonly referring to the AKS-74U, known for its lightweight design, maneuverability, and use in military and law enforcement applications.

A lever-action rifle is a type of firearm that uses a lever, located near the trigger guard, to cycle the action, chamber a round, and eject the spent casing. This iconic design, known for its smooth operation and rapid firing capability, is commonly associated with the Old West and is still popular for hunting and sport shooting today.

Line of sight refers to the straight, unobstructed path between an observer's eye and a specific object or point. It is commonly used in various fields, such as optics and navigation, to ensure clear visual alignment or communication without interference.

a firearm with an extended barrel, such as a rifle or shotgun, designed to be fired from the shoulder for greater accuracy and range compared to handguns.

A lower build kit refers to a group of parts bunched together that are necessary to complete a stripped AR-15 lower receiver. They include a lower parts kit, pistol grip, receiver extension (buffer tube) and butt stock.

A lower parts kit consists of all the small parts necessary to render a stripped AR-15 lower receiver functional except the pistol grip, stock, and the buffer tube (as well as the buffer spring and buffer.

An LPVO (Low Power Variable Optic) is a rifle scope that allows for variable magnification, typically ranging from 1x to around 6x or 10x. This versatility makes it ideal for both close-quarters and mid-range shooting, offering quick target acquisition at low magnification and enhanced precision at higher magnifications.

.22LR (Long Rifle) is a popular rimfire cartridge known for its low recoil, affordability, and versatility, making it ideal for target shooting, training, small game hunting, and plinking.

A modular firearm rail system developed by Magpul, featuring direct-attachment slots that provide a secure, lightweight, and customizable mounting solution for accessories like grips, lights, and bipods.

The M14 is a U.S. military battle rifle, introduced in the 1950s, chambered in 7.62x51mm NATO and capable of both semi-automatic and fully automatic fire. It was used as the standard-issue rifle before being replaced by the M16 and is still employed in certain roles, such as designated marksman duties, due to its long-range accuracy and powerful cartridge.

The M1A is a civilian version of the military M14 rifle, known for its semi-automatic action and chambered in 7.62x51mm NATO (.308 Winchester). It is popular for its reliability, accuracy, and classic design, making it favored for target shooting, hunting, and competition shooting.

A magazine is a spring-loaded container that holds ammunition and feeds it into the receiver.

Derived from the French term for extra large wine bottles, Magnum rounds are extra powerful cartridges.

A mainspring powers the hammer or striker in a firearm to strike a primer to detonate a round.

Match grade refers to firearms, components, or ammunition that are manufactured to the highest precision and quality standards, ensuring superior accuracy and performance. Commonly used in competitive shooting, match-grade products are designed to provide consistent and reliable results under demanding conditions.

In firearms, a micrometer is a precision measuring tool used to accurately measure small dimensions, such as barrel thickness, chamber dimensions, or bullet diameter. It is essential for gunsmithing and reloading, ensuring precise tolerances and optimal firearm or ammunition performance.

Mil-spec, short for military specification, refers to the standards set by the U.S. military for the design, performance, and durability of equipment and materials. In firearms and accessories, mil-spec indicates that a product meets these rigorous criteria, ensuring reliability and compatibility with military systems.

Minute of Angle (MOA) is a unit of angular measurement used in shooting to describe the accuracy or precision of firearms, optics, and sights. It represents a very small angle, equal to 1/60th of a degree. In shooting terms, 1 MOA corresponds to roughly 1.047 inches at 100 yards, which is typically rounded to 1 inch for convenience. When you hear that a rifle is "1 MOA accurate," it means that at 100 yards, the rifle can shoot within a 1-inch group. At 200 yards, this group would expand to approximately 2 inches, and at 300 yards, to about 3 inches, and so on. MOA is often used in scope adjustments, where adjusting by 1 MOA on a scope will move the point of impact by 1 inch at 100 yards. This system is popular because it provides a precise and easily understood way to make fine adjustments at different distances.

(Magpul Original Equipment) is a line of lightweight, durable firearm accessories from Magpul, offering enhanced ergonomics and modularity for grips, stocks, handguards, and more.

A muzzle device is anything mounted on the end of a barrel that affects the firearm. These include flash hiders, compensators, muzzle brakes, thread protectors and sound suppressors.

Muzzle rise, also known as muzzle flip, is the upward movement of a firearm's barrel when a shot is fired, caused by the recoil forces. This motion can affect accuracy during rapid fire, as it moves the sights off the target, requiring the shooter to re-align for subsequent shots.

NATO ammunition refers to standardized cartridges developed and used by NATO member countries to ensure compatibility across their firearms and military equipment. Common NATO rounds, such as 5.56x45mm and 9x19mm, are designed to meet specific performance criteria for reliability, accuracy, and consistency in various military environments.

A gear color known for its earthy green tone, offering effective camouflage and a classic military-inspired aesthetic.

Open tip bullets are projectiles with a small opening at the tip, created during the manufacturing process to improve accuracy by ensuring a more uniform distribution of the bullet's core material. Despite the hollow tip, open tip bullets are primarily designed for precision shooting rather than expansion, making them popular in long-range target and sniper applications.

Outside the waistband (OWB) refers to a style of holster that is worn on the outside of a person's pants or belt, typically allowing for easier access to the firearm. This method of carry is popular for open carry or range use, offering comfort and quicker draw compared to inside-the-waistband options.

PCC, or Pistol Caliber Carbine, is a firearm that combines the compactness and versatility of a carbine with the use of pistol-caliber ammunition, such as 9mm or .45 ACP. Popular for home defense, competition shooting, and training, PCCs offer reduced recoil, lower ammunition costs, and compatibility with pistol magazines for added convenience.

A Picatinny rail is a standardized mounting platform with a series of ridges and slots, used on firearms to attach accessories such as optics, lights, and grips. Its design allows for secure, adjustable placement of these accessories, providing versatility and modularity for a wide range of tactical and shooting applications.

Refers to the compact barrel length and gas system of an AR-style firearm, typically under 10.5 inches, designed for AR pistols or short-barreled rifles (SBRs) to enhance maneuverability.

Pointed soft tip bullets feature a pointed nose with a soft, exposed lead core at the tip, designed to offer better aerodynamics for improved accuracy and range. Upon impact, the soft tip expands, providing controlled expansion for deeper penetration and effective stopping power, making it useful for hunting.

A primer is a small, sensitive component in a firearm cartridge that ignites the gunpowder when struck by the firing pin, initiating the firing process. It is located at the base of the cartridge and comes in various types, such as boxer or berdan, depending on the design and intended use.

Priming in firearms refers to the process of preparing a cartridge by adding a primer, the component responsible for igniting the gunpowder when struck by the firing pin. This step is crucial in ammunition manufacturing or reloading, ensuring reliable ignition and proper functioning of the firearm.

The part of a cartridge that is fired from a firearm, typically a bullet or shot, designed to travel toward a target with precision and velocity.

Pump action is a type of firearm mechanism where the shooter manually slides a forearm or forend back and forth to eject a spent cartridge and chamber a new one. Commonly found in shotguns, pump-action firearms are known for their reliability, simplicity, and ability to function with a variety of ammunition types.

In firearms, QD stands for "Quick Detach," referring to a system that allows accessories such as slings, optics, or suppressors to be easily attached and removed from the firearm without tools. QD mounts and attachments enhance versatility and convenience, enabling users to quickly adapt their setup for different applications or environments.

Recoil, often referred to as "kick," is the backward force exerted on a firearm when it is discharged, caused by the explosion of gunpowder propelling the projectile forward. The intensity of recoil varies based on factors like the firearm's weight, caliber, and design, and managing it is essential for maintaining accuracy and shooter comfort.

A reloading die is a precision tool used in the reloading process to reshape, resize, and prepare spent cartridge cases for reloading with new bullets, powder, and primers. Dies come in various types, such as resizing, decapping, and seating dies, each performing a specific function to ensure the cartridge is properly reformed and ready for reuse.

Rimfire refers to a type of firearm ammunition in which the primer compound is located within the rim of the cartridge base. When struck by the firearm's firing pin, the rim ignites the primer, making rimfire cartridges, such as .22 LR, ideal for smaller calibers due to their lightweight, low cost, and simplicity.

Firearm safeties prevent a gun from firing while engaged.

A safety selector is a mechanism on a firearm that allows the user to engage or disengage the safety, preventing accidental discharge by blocking the trigger or firing mechanism. Often found as a switch, lever, or button, it is commonly used to toggle between "safe" and "fire" modes, and in some firearms, it may include additional settings for burst or fully automatic fire.

(Short-Barreled Rifle) is a rifle with a barrel length under 16 inches, regulated by the ATF under the NFA, requiring a tax stamp for legal ownership.

Semi-automatic firearms are those that automatically load the next round into the chamber after a shot is fired. They differ from fully-automatic weapons in that the trigger must be pulled each time to fire.

A Shepherd's Hook is a small, curved retaining spring used in AK-style firearms to secure the hammer and trigger pins in place within the receiver. It is a simple but effective component that prevents the pins from shifting during operation, ensuring reliable functionality of the fire control group.

Refers to a firearm trigger mechanism that performs only one function—releasing the hammer or striker—requiring the shooter to manually cock the hammer before each shot in non-semi-automatic models.

A single-stage trigger is a firearm trigger mechanism that has a consistent, smooth pull with no noticeable take-up or slack before the break, releasing the shot immediately when the required pressure is applied. This type of trigger is favored for its simplicity and predictability, often used in rifles for precision shooting and tactical applications.

A slide is the upper portion of an automatic pistol that moves back and forth during recoil. It's a key part of the gun that houses the barrel, firing pin, extractor, and guide rod.

A snub-nosed pistol is a handgun with a short barrel, typically 2 inches or less, designed for easy concealment and close-range use. Its compact size makes it ideal for concealed carry, but the shorter barrel can result in reduced accuracy and muzzle velocity compared to longer-barreled firearms.

In traditional terms, a stock is the part of a firearm that the barrel and lock are attached to. In modern terms, it normally refers to the portion of a gun at the rear that a shooter stabilizes with their shoulder.

A firearm ignition system that uses an internal striker, rather than a hammer, to strike the primer, providing a consistent trigger pull and enhanced reliability for handguns and rifles.

A stripper upper receiver is the portion of an AR-15 that the barrel attaches to. A stripped upper lacks any functional components including the barrel, bolt carrier group, dust cover or sights.

Subsonic ammunition refers to bullets designed to travel at a velocity below the speed of sound, typically under 1,125 feet per second (depending on atmospheric conditions). This reduces the loud crack associated with a sonic boom, making it ideal for use with suppressors and offering quieter operation for hunting, tactical, or recreational shooting.

Tannerite is a brand of binary explosive targets, made from a combination of ammonium nitrate and aluminum powder, that detonates upon impact from a high-velocity bullet. It is commonly used in shooting sports for long-range target practice, creating a visible explosion when hit.

Federally required approval and fee issued by the ATF for purchasing and owning NFA-regulated firearms, such as suppressors, short-barreled rifles, and machine guns.

A trigger is the mechanism on a firearm that a shooter actuates to drop a hammer or striker on a cartridge's primer to fire the weapon.

A small but essential component in a firearm’s lower receiver that secures the trigger assembly in place, ensuring proper function and stability during operation.

A firearm component, especially in AK-style rifles, that reinforces the receiver and provides a mounting point for the barrel and other essential parts.

Firearm trigger system that features a light initial take-up followed by a distinct second stage, allowing for greater control and precision before firing.

An AR-15 Upper Parts Kit includes a charging handle, dust cover, and forward assist.

An AR-15 upper receiver is the top half of an AR-15 rifle, which houses the barrel, bolt carrier group, charging handle, and other components like the gas block and handguard

A vertical grip is an accessory attached to the underside of a firearm's forend, providing a perpendicular handle for the shooter’s support hand. It enhances control, stability, and maneuverability, especially during rapid firing or while using heavier firearms.

A wadcutter is a type of bullet with a flat nose, designed for target shooting, which creates clean, round holes in paper targets for easier scoring. It is commonly used in revolvers and is typically made of soft lead for lower recoil and greater accuracy at short ranges.

Weaver normally refers to an alternative optics mounting rail system which is visually similar to the standard Picatinny rail, but are not compatible with each other. Generally considered obsolete.

Waver stance is a two-handed pistol shootin stance where the shooter slightly blades themselves to the target, and pushes outward with a straight shooting arm and pulls rearward with a bent suport arm. Still popular today, but overshadowed by the Isosceles stance.

Windage refers to the horizontal adjustment of a firearm's sights to compensate for the effect of wind or other factors that may cause the bullet to drift left or right during flight. It is also used to describe the lateral deviation of a projectile due to wind.