Gun Vocabulary Words
ACP - Automatic Colt Pistol. Colt's proprietary designation for a type of rimless cartridge design for reliable feeding from the magazine in a semi-automatic handgun. Example: .45 ACP
Action - The receiver of a gun containing the breech-locking and firing mechanism. The serially-numbered, legal soul of a firearm. Major types are: Boxlock, Sidelock, Blitz, Falling Block and Bolt
Ambidextrous Safety - A safety catch that can be operated by either hand. Of benefit to left-handed shooters and in the event of an injury to the right hand.
Automatic [Action] - A type of firearm which, utilizing some of the recoil or some of the expanding-gas energy from the firing cartridge, cycles the action to eject the spent shell, to chamber a fresh one from a magazine, to cock the mainspring and to fire again. Such a firearm will fire continuously as long as the trigger is held back, until the magazine is empty. A machine gun.A firearm thus activated, but which shoots only one bullet with each separate pull of the trigger, while often erroneously referred to as "automatic" is more properly termed Semi-Automatic.
Automatic Safety - A safety catch on a break-open gun that resets to the "safe" position each time the gun is opened, usually via a limb attached to the toplever spindle
Backstrap - Rear, metal, part of a handgun---which together with the frontstrap, provides a mounting frame for the grips
Ballistics - The study of the action of propellant powders upon projectiles, their speeds, energies and trajectories. Ballistics can be categorized into three phases: Interior (the projectile's behavior inside the bore), Exterior (the projectile's behavior in flight), and Terminal (the projectile's behavior upon contact with the target).
Barrel - An essential component of a firearm; a tube, sealed at one end (the breech) in which a propellant is ignited, whose rapidly expanding gasses create powerful pressure to force a single or multiple projectiles through its bore, out the open end (the muzzle) and down range towards a target.
Barrel Length - The length of a barrel as measured from the muzzle to the standing breech in a break-open gun or to the bolt face in a closed bolt-action rifle, including the chamber. A revolver barrel measurement, by convention, does not include the cylinder, only the barrel itself.
[In] Battery - A condition of a firearm where it is loaded, with the action closed, cocked and (with the possible exception of the safety catch) ready to fire
Bayonet - A knife, optionally mountable to the muzzle-end of a rifle or musket to add the function of a spear. For close-range combat and as a last resort when the ammunition is exhausted
Benchrest - (1) A stout table from which to fire a rifle, removing as much human error as possible in the interest of testing rifles, loads and/or adjusting sights. (2) Both a type of rifle and the competition in which it is used. A heavy, invariably single shot rifle, made for stationary target shooting. The rifle often having a flat underside for unaided stability on the bench. An exercise for ultimate accuracy of rifle and load with the variables of human marksmanship purged from the formula.
Bipod - A two-legged stand, usually hinged and attached to the forend of a rifle, for use as a rest in the interest of increased stability in aiming
Black Powder- The first successful propellant harnessed for use in firearms. Composed, generally of 3 parts potassium nitrate, 2 parts powdered charcoal and 1 part sulphur. Black powder explodes---expending its energy in an instant of time, produces volumes of vision-impairing smoke, its residue promotes rust in gun bores and it is unpredictably dangerous to handle. Black powder was replaced in the marketplace by nitro-glycerin-based powders around the turn of the last century because they burned more slowly (maintaining pressure on the projectile longer during its travel through the bore, allowing higher velocities), did not blind shooters with the smoke, did not promote rust in bores and was much safer to store and to handle. For these reasons, it is dangerous to shoot modern nitro powders in vintage guns (such as those with barrels of damascus steel) originally designed and contoured for the pressure curve of Black Powder
Blue - A chemical rust process that produces a very dark, almost black, blue finish to the steel parts of a firearm which enhances the appearance and provides some protection from unwanted rust. Sometimes it can have a slight brownish undertone. The percentage of blue finish remaining on a gun can be a proxy for describing its condition
Bolt - A cylindrical shaft, controlled by an attached lever, which rotates a partial revolution engaging locking lugs in complementary recesses, contains an internal spring-loaded firing pin, and becomes the breech-block of a bolt-action firearm
Bolt Action - An action type, most frequently used on rifles, perfected by Peter Paul Mauser in 1898, whereby a cylindrical shaft, controlled by an attached lever, manually feeds a cartridge into the chamber, rotates a partial revolution engaging locking lugs in complementary recesses in the front receiver ring, allows firing by the fall of an internal spring-loaded pin, opening, extraction, re-cocking and ejection with the same lever in preparation for the next shot
Bolt Stop - A displaceable flange, usually towards the rear of a bolt action firearm which in normal position, either detented or under spring tension, prevents the bolt from falling completely out the rear when cycling the action. It is readily moved aside by the bolt stop release to allow removal of the bolt for cleaning or disassembly
Bore Sight(v) - A process by which sights are adjusted to converge on the same line as the bore. Accomplished by placing a rifle in a rest, sighting down the open bore on a prominent distant point at an appropriate range, then aligning the sights to superimpose on the same point. Alternatively, may be accomplished with a device known as a collimator. The process should conserve ammunition when sighting-in a rifle by approaching proper sight adjustment before actually firing the rifle with live ammunition
Butt - The end of a gun stock; the part that rests on the shoulder when the gun is mounted
Cal. orCalibre - System of measurement for the internal bore diameter of a rifled-barreled firearm (rifle or pistol) based on the decimal part of an inch. For example, .25 calibre and .250 calibre both signify a bore size of 1/4 inch. American calibre designations refer to the distance from land to land, not groove to groove. Ammunition companies' marketing departments occasionally take liberties with exact measurements. For example, a .270 Winchester bullet actually measures .277 inch in diameter
Cant(v)- To tilt a gun to one side or the other, complicating sighting considerably. Can cause material loss of accuracy, particularly with a rifle at longer ranges. Some better long range target rifles are equipped with Spirit Level sights to help the marksman control canting
Carbine - A general term referring to relatively short-barreled, quick-handling rifle, often intended for use on horseback.In Winchester lever-action terminology, a carbine has a single barrel band.In German, a Stutzen.
Cartridge - In its definition valid from circa 1870 to the present: a small usually cylindrical packet, containing a detonating primer, a powder charge, a load---either a single projectile for a rifle or a quantity of small pellets for a shotgun---and possibly some attendant wadding. The cartridge is placed into the breech of a firearm, comprising all required consumables for the firing of the weapon
Chamber - An area at the breech end of a barrel, of about the diameter of the cartridge for which the gun was intended, and into which the cartridge is inserted. The nominal length of a shotgun chamber will accommodate the loaded cartridge for which it was intended and allow for its crimp to open fully when the cartridge is fired. Although one can easily insert a longer-than-nominal-length loaded cartridge in a shotgun chamber, it is not advisable to do so because when it is fired the crimp will open into the forcing cone. Because of the taper of the forcing cone, the crimp will not be able to open fully and the gun will develop far greater pressure than it was designed to handle.
Choke - A carefully measured constriction of the bore of a shotgun at the muzzle, designed to control the spread of the shot as it leaves the barrel.
Choke tubes - Short, interchangeable cylinders, of subtly different internal tapers, that screw into a threaded recess at the muzzle of a shotgun. By inserting different choke tubes, one can alter the shot pattern thrown by the gun. Choke tubes should be tightened until snug. Guns fitted for choke tubes should never be fired without tubes in place.
Clip - A simple, disposable narrow spring-lined channel-rail in which cartridges are supplied for military weapons. The shooter positions the clip vertically above the firearm's magazine, then pressing down with the thumb, slides the cartridges from the clip and down into the magazine. Also: Stripper Clip or Charger (THIS IS DIFFERENT THEN A MAGAZINE THAT HOLDS BULLETS)
Cock (n) - A firearm's exposed hammer.
Cock (v) - To tension the mainspring of a gun in preparation for firing, such as by pulling back the external hammer, pulling back the slide of a pistol, or opening and closing the barrel(s) of a break-open gun.
Cocker/De-Cocker - A type of action on a break-open gun or rifle where, in place of a traditional top tang safety, a somewhat more robust tab is fitted. Normally such a gun is carried in the field loaded, but with the action not cocked---an exceedingly safe condition. Then, when ready to fire, the shooter, instead of pushing a safety tab forward, pushes this larger tab forward, cocking the mainspring, making the gun ready to fire. Then, if the shot is not taken, he may simply slide this tab rearwards again, de-cocking the gun and returning it to the still-loaded, but very safe position. Or, in German: Handspanner.
Cocking Indicators - Small devices attached to the internal hammers of a break-open gun and visible from the exterior of the gun to show when each lock is cocked and when it has been fired. These are usually in the form of protruding pins on a boxlock gun or in the form of engraved or gold inlaid lines on the tumbler pins of a sidelock gun
Crosshairs - Basic form of telescopic sightreticle, having one fine vertical line and one fine horizontal line with which to establish the point of aim.
Cylinder - That part of a modern revolver that holds cartridges in separate chambers radially around a central hingepin. The cylinder revolves as the handgun is cocked, bringing each successive cartridge into position, and locked into alignment with the barrel for firing.
DAor Double Action - An action type, typical on revolvers, where pulling the trigger through a long stroke revolves the cylinder, cocks the hammer and fires the gun---and alternatively, where manually cocking the hammer and then pulling the resulting single-stage trigger fires it also.
Deringer - A small, single-shot, percussion pistol designed and manufactured by Henry Deringer of Philadelphia.
Derringer - Spelled with two rs, any very small easily concealed handgun.
Double Action - An action type, typical on handguns, where the hammer may be cocked manually prior to each shot, OR, one may pull the trigger through a long throw which cocks the hammer (and in the case of a revolver, advances the cylinder) and fires the revolver in one complete motion
Dust Cover - A small hinged or sliding door covering the ejection port of a firearm to prevent detritus from clogging the works.
Ejectors - Fittings inset into the breech end of a pair of barrels of a break-open gun that kick out fired shells, while only raising unfired shells enough to be removed by hand. Recognizable at a glance on the breech end of a double gun because the fitting is split in two---one ejector for each barrel.
Elevation- Adjustment of the point of impact of a firearm in the vertical plane; the knob used on an iron sight or telescopic sight to raise or lower the point of impact.Photo
Energy - Capability to perform work. As measured in foot-pounds, the amount of force it takes to lift and object weighing one pound, one foot. To calculate the energy, in foot-pounds, of a bullet in flight at any point on its trajectory:
W = Weight of the bullet in grains. V = Velocity in feet per second
Erosion - Deterioration of the inner surface of a firearm's barrel due to the intense heat of a cartridge's discharge. High-velocity rifles are particularly susceptible to this wear, especially near the throat.
Extractors - A fitting inset into the breech end of a pair of barrels of a break-open gun. When the gun is opened the extractor lifts the cartridges so they may be removed by hand. Recognizable at a glance on the breech end of a double gun because the fitting is solid---one extractor taking care of both barrels together.
Eye Dominance - Although we have two eyes for depth perception and for spare parts, there is a natural tendency for one eye (the master eye) to take precedence over the other, regardless of the relative visual acuity of each eye. It is a fortunate condition when the eye on the side of the shoulder where one is comfortable mounting a gun is also the dominant eye.
To test for eye dominance, pick out a small object several feet away. With both eyes open, center your right index finger vertically over the object. Close your right eye. If your finger appears to jump to the right, you are right eye dominant. Then open your right eye and close your left eye. If your finger remains in position in front of the object, you have confirmed your right eye dominance. Alternatively, if in the above test, upon closing your right eye your finger remains in position covering the object, you are left eye dominant. If you close your left eye instead and your finger appears to jump to the left you have confirmed your left eye dominance.
Eye dominance problems can be treated with 1. A severely-cast, crossover stock to bring the dominant eye in line with the gun's line of sight, 2. A patch over the dominant eye, or just a small piece of frosty Scotch tape on shooting glasses intercepting the dominant eye's line of sight, 3. Fully or partially closing the dominant eye, or 4. Learning to shoot from the dominant-eye shoulder. While less convenient, methods that retain the use of both eyes better preserve the ability to perceive depth in three-dimensional space---a great benefit in wingshooting.
Eye Relief - The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.
Feed Ramp - An inclined, polished area on a repeating firearm, just behind the chamber, that helps guide a cartridge into the chamber when pushed forward by the closing bolt
FFL - Federal Firearms [Dealer's] License. Under federal law, to ship a firearm, a selling dealer must have in his possession a copy of the receiving dealer's license
Firearm- A device which, on demand by activating some sort of switch like a trigger, ignites a very-rapidly burning propellant or an explosive, expels a projectile such as a bullet, or projectiles such as shot, from a tubular barrel (or barrels) with sufficient force as to cause acute bodily harm to the target, animal, or person which it hits.
Flinch (v) - To jerk a firearm off target inadvertently at the instant of firing in timid anticipation of recoil.
Fluid Steel barrels - Barrels made of homogeneous steel (not damascus steel) --- standard practice for over a century
Fluted Barrel - A rifle or pistol barrel, into which longitudinal grooves have been milled. Fluted barrels, while more expensive to make than round barrels, dissipate heat more rapidly and they provide a better stiffness-to-weight ratio.
Follower - A smooth, sometimes contoured plate, within a magazine, at the top of a spring, across which cartridges slide when being loaded into a chamber
Frontstrap - Front, metal, part of a handgun's grip---which together with the backstrap, provides a mounting frame for the grip panels
Gauge - System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight equals one pound. The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.) The Gauge/Bore system is also used, by convention, to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel rifles