Gun terms and glossary
Pronounced “nineteen-eleven,” this refers to the popular semi-automatic pistol (and all clones) designed by John Moses Browning and adopted by the US army in the year 1911.
The mechanism of a firearm that allows the introduction of a new cartridge for firing and removal of the spent casing. Common action types include bolt-action, lever-action, pump-action, break-action, and semi-automatic (recoil, inertia, or gas-operated).
A type of (usually rear) iron sight that contains one or more apertures or openings through which the shooter looks to align the front sight and the target. More common on rifles than on other types of firearms.
A general term used to describe the various clones of the AK-47, AKM, AK-74 rifle and variants. AK stands for Avtomat Kalashnikova, Russian for “automatic (firearm) Kalashnikov,” for its designer, Mikhail Kalashnikov, who designed the first accepted version of the weapon in 1947.
A general term used to describe the AR-15 type rifle and clones, originally designed and developed by Eugene Stoner and Jim Sullivan. Often incorrectly defined to mean “Assault Rifle,” the AR in the name originally came from “ArmaLite Rifle.”
Automatic, autoloader, auto
This term may refer informally to any semi-automatic firearm, or it may refer to fully automatic machine guns that are capable of firing multiple rounds with a single pull of the trigger. Usually the latter are called “full-auto” or “fully automatic” for clarity.
The barrel is the tube-shaped part of a firearm through which the projectile travels. A firearm may have more than one barrel.
Until the end of the 19th century, all firearms burned the same type of gunpowder or “black powder” in different granulations. Today, antique or replica black powder firearms are used for fun, hunting, and competition, but almost all modern firearms designs use “smokeless powder” which is more stable, powerful, and clean-burning than black powder, in addition to being less corrosive. “Blackpowder substitutes” are modern powders that can safely be used in black powder firearms.
In common usage, a bead or bead sight is a basic type of front sight, usually on a shotgun barrel, comprising a simple metal or polymer sphere brazed or screwed into the barrel or sight rib. You might hear old-timers say phrases like, “I drew a bead on him,” which means to aim carefully.
The interior of the firearm’s barrel, as in “be sure to clean the bore” or “inspect the bore for copper fouling.”
Basepad, base pad, baseplate
Typically used to describe the removable bottom portion of a detachable box magazine.
Shotguns can fire a wide range of ammunition types. Birdshot is composed of very small lead (or bismuth, or tungsten, or steel) pellets that, when fired, create a cloud of tiny projectiles suitable for hitting flying birds or airborne targets.
Brake, muzzle brake
A device fitted or integral to a firearm’s muzzle is intended to reduce the amount of recoil the shooter feels by redirecting the expanding gases to the side. Sometimes incorrectly spelled “muzzle break.”
Commonly used to describe empty cartridge casings. Traditionally, most cartridge casings are made of brass or contain brass.
The part of the barrel/action that is opened to allow insertion of ammunition, usually at the rear of the barrel. In basic orientation terms, the breech is the opposite of the muzzle.
Much larger than birdshot, buckshot is so named because it is composed of pellets suitable for hunting larger animals like “bucks”/deer. Sizes of common buckshot pellets range from 000 or “triple-aught” buck (at .36” in diameter), through 00 “double-aught” (at .32”), and down to #4 buck at .24” per pellet. Buckshot is often used for self-defense or tactical purposes.
Bullet trap or bullet stop
Often used in indoor shooting ranges, a backstop that safely catches and contains fired projectiles.
This term refers to the capability of some submachine guns or machine guns to fire 2, 3, or 4-round “bursts” with each press of the trigger. An internal mechanical device limits the burst to the specified number of rounds.
Butt, buttstock, buttpad, buttplate
On a rifle or shotgun, the butt is the rear of the gun where it meets the shooter’s shoulder. The buttstock is the entire portion of the stock to the rear of the firing grip. This may be a separate piece, or it may be integral with a one-piece stock. The buttpad or buttplate is a separate piece at the back of the buttstock, which protects the shooter from excessive recoil or protects the buttstock when placed on the ground, or both.
In common usage, “caliber” refers to the dimensions of the firearm’s ammunition and barrel diameter. This may be designated in metric or “standard” units. A pistol in caliber 9x19 (also known as 9mm, 9mm Para, 9mm Parabellum) has a bore/projectile diameter of ~9mm, with a case length of 19mm. Similarly, a pistol chambered in .45 ACP has a bore/projectile diameter of ~.45” and the case dimensions specified by the .45 Automatic Colt Pistol cartridge designer.
This term may be used specifically (as above) or generally, as in “I prefer .30-caliber rifles”—referring to all rifles that fire a projectile of ~.30” in diameter, regardless of their case dimensions.
Technically, a carbine is a shortened version of a military service rifle, or historically, a shortened version of the infantryman’s musket or rifle suitable for use by cavalry. Informally, any short rifle may be called a carbine. Both pronunciations—CAR-bean, like a can of beans, and CAR-bine, which rhymes with “line”—are considered correct.
In common, non-military usage, a cartridge is a complete unit of ammunition, composed of the case, primer, gunpowder, and projectile/s in a single, self-contained unit. See: Round.
Case, casing, shell casing
In common usage, a “shell casing” or cartridge case is what contains the primer, gunpowder, and projectile/s in a self-contained unit. Modern casings are typically metal (usually brass, steel, or aluminum) for handguns and rifles, and plastic with a steel or brass base/rim for shotguns.
The rear portion of the barrel (or cylinder, in revolvers) where the cartridge is inserted in preparation for firing.
A tapered internal constriction near the end of a barrel. Most are typically used on shotguns (to improve shot pattern and increase effective range), but some target-grade muzzleloading rifles and pistols may also have a similar feature. Common shotgun choke designations include Cylinder, Skeet, Improved Cylinder, Modified, and Full.
The process of completely unloading a firearm and demonstrating that it is safe. “Clear” may also refer to a “safe range” in certain shooting competitions.
Clip, stripper clip, en bloc clip
Archaically, the term “clip” was often used to refer to a removable box magazine, even by militaries and manufacturers. However, modern usage dictates that a clip is a device for holding cartridges together for ready insertion into a firearm’s magazine. A stripper clip is used to strip fresh rounds into an internal or detachable magazine and is then discarded, while an “en bloc” clip is inserted fully into the magazine (example: M1 Garand rifle) and is ejected with the empty casing when the firearm runs empty.
The act of manually pulling back the hammer, slide, or cocking piece of a gun, preparing it to be fired. The “cock” is also the part of a flintlock firearm that holds the flint and which falls when the trigger is pulled.
A range command or condition indicating it’s safe to walk down range, replace targets, etc. Usually, no firearms may be handled while the range is cold.
Similar to a muzzle brake, a compensator is a device attached or integral to a barrel’s muzzle, designed to reduce muzzle “flip” or climb by redirecting the expanding gases upward.
Traditional telescopic sights (or scopes) contain physical or etched-on vertical and horizontal lines to aid with aiming. They are known as crosshairs due to their intersecting, cross-shaped design and thin profile.
In a revolver, a rotating cylinder contains multiple chambers. As the mechanism rotates each chamber into alignment with the barrel, the next projectile can be fired.
A shotgun term designating that there is no choke or restriction at the front of the barrel.
The action or part that safely lowers the hammer or removes tension on the striker when the shooter doesn’t wish to immediately fire a shot. Common on many double-action semi-automatic pistols.
This acronym is used to describe “traditional” double action/single action semi-automatic pistols, such as the Beretta 92 series, the SIG P220 series, and the CZ75 series. These pistols have two trigger modes: 1. Double action (meaning the trigger performs both the function of cocking the hammer and firing the firearm) for the first shot; and 2. Single action for subsequent shots (meaning the trigger, once the hammer is cocked by the user or by the reciprocating slide after firing a shot, performs the single action of firing the next shot until the pistol is decocked or returned to double-action mode).
Double action, DA
This term refers to a firearm with a trigger system in which the trigger performs two functions: 1. Cocking the hammer (or striker), and 2. Releasing the hammer/firing a shot. Almost all modern defensive revolvers are double-action. However, on a traditional double-action revolver, the hammer may also be manually cocked by the shooter to fire a “single action” shot if desired.
Double action only, DAO
A firearm (usually a revolver or semi-automatic handgun) with a trigger that returns fully forward, and a hammer or striker that returns to its down/forward or rested, uncocked position after each shot. The hammer or striker may not be manually cocked for a “single action” shot in this design.
When a shooter fires two shots in rapid succession.
Down range, downrange
The area of a formal or informal shooting range in front of the firing line, where shooters may place targets and safely discharge their firearms.
Dram, dram equivalent
Shotgun projectile weights are typically measured in ounces in the US, and shotgun powder weights are often listed in drams or (usually) smokeless powder “dram equivalents” on commercial shotgun ammunition packaging. (A dram is an archaic weight measure left over from the days of black powder shotgun cartridges, but is still used today. Using that measure, 16 drams of black powder equal one ounce of weight, and 256 drams of black powder weigh one pound.)
Firing a firearm when it’s “dry” means “unloaded.” For checking proper function or for training purposes, dry firing can be a useful practice. Certain competitions also require you to dry fire your firearm in a safe direction after unloading and showing “clear” to the Safety Officer. Always remove all ammo from the area and triple-check that the gun is unloaded before dry firing. Also, refer to your owner’s manual: some firearms cannot safely be dry-fired without damaging the gun.
A round of ammunition that does not fire when the primer is struck by the striker or firing pin. A dud may be caused by deterioration (or absence) of the priming compound, a faulty primer, a weak hammer/striker spring, contaminated powder, or other factors.
Dummy, dummy round
A training or action-proving round that contains no primer or powder.
A gun-culture term for proper hearing protection. Often used by Safety Officers or trainers in the phrase “eyes and ears.”
A solid or spring-assisted firearm part that applies pressure to (usually) the left part of the rear surface of the fired cartridge case and pushes it out of the ejection port.
The extractor is a claw-like part that grabs onto the rim of the case and helps pull the spent case from the chamber.
A gun-culture term for proper protective eyewear. Often used by Safety Officers or trainers in the phrase “eyes and ears.”
Failure to eject (FTE), stovepipe
A type of malfunction in automatic or semi-automatic firearms where the fired/empty case is not completely ejected from the firearm, and may remain in the chamber or stuck partially in the ejection port. In pistol training, this may be referred to as a “stovepipe” when the empty brass is stuck between the slide/ejection port and the rear of the barrel, and it looks similar to an old stovepipe on top of a wood-burning stove.
Failure to feed (FTF)
A type of malfunction where the cartridge fails to properly enter the chamber for firing.
Failure to fire
A type of malfunction when the trigger is pulled and the hammer, cock, or striker falls, but the primer, percussion cap, or flintlock charge fails to ignite the primary powder charge, and no projectile is fired.
For modern cartridge-firing guns, the NRA recommends waiting 60 seconds after a failure to fire before opening the action, with the muzzle pointed in a safe direction, and 2 minutes for a muzzleloader.
At a range, the line or area that shooters stay behind to safely fire their guns down range.
This part is what impacts the primer, causing the powder to ignite, and fire the gun.
This type of ignition system (for muzzleloaders) employs a piece of sharp flint to strike a metal surface, making sparks that ignite the priming charge of black powder, which then ignite the main charge and fire the gun. Sometimes informally called a “rock lock.” (Flint is a type of rock.)
The integral or separate part of a firearm’s stock where the shooter’s “support hand” grasps the firearm, usually below the barrel.
This term describes any type of firing debris, carbon, lead, wax, or plastic in a firearm’s action or bore which can impede regular function, impair accuracy, and damage the gun if not removed through cleaning.
Four rules, or the four rules of firearm safety
The four rules of firearm safety were initially developed by Colonel Jeff Cooper, the father of the Modern Technique of handgun shooting. There are many variations in wording, but the main points are:
- 1. Always treat firearms as if they are loaded;
- 2. Never let the muzzle cover anything you are not willing to destroy (in other words, always keep guns pointed in a safe direction);
- 3. Keep your finger off the trigger until your sights are on the target and you’re ready to shoot,; and
- 4. Be sure of your target and what’s behind it.
In gun speak, furniture refers to the buttstock and forend on a shotgun or rifle, usually when discussing wood parts, but also may refer to the buttstock, forend, and grip set of a modular rifle like the AR-15.
In firearm terms, “gauge” refers to the size of a shotgun’s bore diameter or caliber. The smaller the gauge, the larger the bore diameter. A shotgun’s gauge was originally determined by the number of pure lead balls of bore diameter that would weigh one pound. The larger the gauge/ball, the fewer balls would weigh one pound. So, a 20-gauge shotgun (where 20 lead balls of bore diameter weigh one pound) has a smaller bore diameter than a 12-gauge shotgun (where only 12, larger, lead balls weigh one pound).
The term “gauge” may also refer to a measuring device to check cartridge headspace in reloading, or timing in a semi-automatic or automatic firearm, or headspace when setting barrel/chamber dimensions, or for other uses.
Any of various semi-automatic, short recoil-operated handguns designed and produced by the Austrian company, Glock Ges.m.b.H (trademarked as GLOCK). Glocks are now made in both Austria and the USA.
Bullet weights and powder charges for rifles and shotguns are typically measured in grains in most western countries. Grain is not an individual flake or granule of gunpowder, but rather a grain is a measurement of weight equal to 1/7,000th of a pound (there are 7,000 grains in one pound).
The part of a firearm held by the firing hand (which manipulates the trigger). A grip can be a separate, removable piece, as on most revolvers or AR-15s, or it can simply describe the area of the wood or polymer buttstock of a rifle or shotgun where you grip it. A pistol’s grip may be integral to the frame, like on many polymer handguns, or it may have removable “grip panels” that the user can remove, replace, and customize as desired.
A semi-archaic term describing a very sensitive trigger that will fire the gun with very little pressure. The term derives from the hyperbolic statement that the weight of a single hair is enough to fire the shot.
The (usually external) part of some firearms is manually or mechanically “cocked,” or retracted against spring tension, and which is released when the trigger is pulled. The hammer then falls and strikes the firing pin or percussion cap, firing the gun.
In common usage, a handgun is a firearm designed and intended to be used by one or both hands, rather than resting a portion of the firearm against the shooter’s shoulder or cheek.
Hangfire or hang fire
More common in black powder firearms, or when using surplus cartridges of questionable quality and age, a hangfire is a momentary delay between the press of the trigger and the ignition of the primary powder charge. This can be a fraction of a second, or up to several seconds in extreme cases, and can be very dangerous if the shooter moves the gun off target or (worse) opens the action before the round discharges.
Hollow point, hollowpoint, JHP
A bullet with a hollowed-out nose causes the bullet to expand on impact, delivering more energy to the target and controlling penetration. “Jacketed hollow point” or JHP is a common acronym used in defensive or hunting ammunition. The “jacket” is a copper (or similar) metal sleeve swaged or plated onto the exterior of a lead bullet.
The means for carrying a firearm when not in the shooter’s hand. Usually, this term relates to a handgun, typically on the user’s belt, though there are pocket holsters and other holsters intended for mounting to tactical vests or in automobiles, etc. Most holsters today are made of polymer/Kydex, leather, or nylon.
Hot range, “range is hot”
This term describes an informal or formal shooting range that is being used or approved for live fire. It is not safe to walk downrange because firearms may be loaded and fired at any time.