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Shooting Glossary


The mechanism by which the rifle is loaded and fired, also covering the withdrawal and expulsion of the fired round. Top

A weapon which will continue to load and fire so long as the trigger is pressed and there is ammunition available in the feed system. Top

Noted as C, this term is a mathematical ratio between the bullet’s sectional density and its coefficient of form, a construct originally designed around a "standard" bullet form. Top

The study of projectiles in motion, to include many aspects, such as extreme range and trajectory, as well as energy ratings from muzzle to termination of flight. Exterior (also external) ballistics treats the bullet after it leaves the muzzle. Interior or internal ballistics deals with the bullet in the rifle from primer detonation to bore travel. Top

For our purposes, the mortise in the rifle stock which contains the barrel and action of the rifle. Top

The cartridge case which has a band ahead of the extractor groove is a belted case. The band or belt is generally a feature of the so-called magnum cartridge. The band is used as the headspace gauge in the belted round. Also, the wise reloader uses the belt as a gauge to measure pressure, miking the belt after one firing and then miking again after consequent loads to inspect for further expansion. Expansion across the belt indicates a condition of high pressure (as well as possible brass fatigue. Top

A notch cut in the weapon’s firing pin, striker or other component, into which the sear engages to hold the component ready to fire. Top

System of operation analogous to blow-back but in which the bolt is fixed and the inertia of the barrel at the moment of firing, the cartridge in place. Breech pressure then forces the barrel forward to open the breech. Top

Also boat-tail, or BT. A bullet with a tapered heel. The shape of the boattail bullet aids its flight in the atmosphere, and boattails will usually show a higher retained velocity at long range over flatbase bullets of the same caliber and weight, all other things, such as profile, being equal. However, in many practical aspects, the boattail is not a distinct advantage, such as in the short- to modest- range hunting rifle. Top

That part of a weapon which closes the breech; it may also perform the functions of loading and extracting, and often carries the firing pin or striker. Top

Breech closure of a small arm by means of a hand-operated bolt moving in prolongation of the weapon’s axis. May be a ‘turnbolt’ in which the bolt is pushed forward and then turned down to lock, by means of a handle; or a ‘straight pull’ in which the manual action is a simple to-and-from movement and the bolt is turned and locked by cam action. Top

A component which supports the bolt in its movement and generally contains the means of rotating or otherwise locking it. Top

The interior of a weapon’s barrel, from the face of the bolt to the muzzle, including both the chamber and the rifled portion. Top

A means of matching the sight picture with alignment of the bore. This is accomplished by securing the rifle, looking through the bore, "aiming the bore" at a target, and then adjusting the sights until they are "looking" in the same place. In addition, a bore sighter (also called a collimator) may be used, which is an optical device that attaches to the muzzle of the rifle. Again, the sights are adjusted to match the direction the bore is pointing to. Bore sighting aids in getting that first shot "on the paper." By firing first rounds from an unsighted rifle at very close range, much the same advantage is realized. Top

A method of ammunition supply in the form of a metal or plastic box, either detachable from the weapon or integral with it, below, above, or to one side of the weapon. The cartridges are held inside the box and impelled to the magazine mouth by a spring. Top

That portion of the rifle barrel which will contain the load, be that load a cartridge or, in the case of a muzzle-loader, a powder charge and projectile. Top

A resilient component at the rear of an automatic weapon against which the bolt or breech-block comes to rest after recoil. It absorbs some of the recoil energy and assists in controlling the rate of fire. The resilience may be due to springs, rubber, oil, or pneumatic media. Top

Colloquial term for a rifle in which the mechanism is set well back in the stock so that the end of the receiver is against the firer’s shoulder. This design permits the use of a full-length barrel in a weapon which is shorter overall than one of conventional stocked shape. Top

That part of a shoulder arm which rests against the firer’s shoulder and transfers the recoil force to his body. Top

The diameter of the interior of a gun barrel, defined as the diameter of a cylinder which will fit inside the lands of the rifling. More commonly, the diameter as measured from the top of one land to the top of the opposite land. Top

Simply, a short rifle. The Model 94 carbine, for example, wears the 20-inch barrel, while the original rifle had a 26-inch barrel. It is not incorrect to call a short-barreled rifle a rifle, however. But when a reference to "carbine" is made, one knows that a shorter rifle is being spoken of. Top

A unit of ammunition, consisting of a cap, cartridge case, propelling charge and bullet. Also called a ‘round’ of ammunition. Top

Distance between the face of the bolt and the rear of the chamber when the breech is closed. A critical dimension, since if it is insufficient the bolt will not close and if it is too great the cartridge may set back on firing and burst. Top

The rearward portion of the barrel which has been reamed, using a specific reamer to create a specific cartridge dimension. The cartridge itself fits into this section of the barrel for firing, held there by the breech. That portion which lies ahead of the neck portion of the chamber is called the leade or throat. Free-bored chambers have more leade than standard chambers. Top

A lever or switch which allows the firer to select single shots or automatic fire in certain types of weapon. Also called a ‘selector’; may be combined with the safety catch. Top

A metal or plastic frame in which cartridges are held and from which they can be loaded into the magazine of a weapon. The loaded charger is positioned opposite the magazine and the cartridges are swept from the charger into the magazine by thumb pressure. Common on bolt-action rifles, occasionally found on automatic pistols and rifles. Top

A device used to calculate the velocity of a projectile. Modern chronographs also allow the gathering of other data, such as standard deviation from the mean velocity, extreme spread, highest velocity in the string, lowest velocity in the string, and an average velocity, rather than one simple velocity statement. Top

A metal frame in which cartridges are held and from which they are loaded into the weapon’s breech. Differs from a charger in that the loaded clip is inserted into the magazine, the cartridges are removed from it one at a time as they are loaded, and the empty clip is usually ejected as the last cartridge is removed. The clip forms an integral part of the feed system; without it, the weapon cannot be used. Found on bolt-action rifles, notably the Garand. Top

Device attached to, or forming part of, the muzzle of a weapon and which diverts some of the escaping gas upwards or to one side so as to counter the tendency of the gun muzzle to rise or swing during automatic fire. Top

The slack which must be taken up before the trigger disengages the sear is called creep. A military-type or two-stage trigger may have intentional slack and this slack is not generally referred to as creep, whereas a trigger which is supposed to activate directly following pressure from the pad of the finger but which has slack is known as a trigger with creep in it. Top

The very last portion of the muzzle of the rifle, sometimes indented or recessed to protect the rifling. Top

The theoretical rate of fire of an automatic weapon assuming a continuous and infinite supply of ammunition – i.e., disregarding the need to change magazines or belts. Top

The series of operations necessary to cause a weapon to fire on round and return to a state of readiness. May be performed by hand or by an automatic mechanism. It consists of:

1 Chambering the round
2 Closing and possibly locking the breech
3 Firing
4 Unlocking and opening the breech
5 Extracting the spent case
6 Ejecting the spent case
7 Cocking the firing mechanism
8 Feeding the next cartridge into place

Not all of these functions may be present; e.g., a blowback weapon does not perform unlocking and locking, a caseless weapon does not perform extraction and ejection, and they may not be in the order given - e.g., cocking can take place before extraction – but the entire cycle must be followed by any small arm. Top

A mechanism in self-loading weapons which disconnects the trigger from the firing mechanism after each shot. It can only be reconnected by the firer releasing the trigger. It prevents a semi-automatic weapon firing in the automatic mode. In selective-fire weapons it is thrown out of action by the selector or change-lever. Top

A pistol firing mechanism which permits firing in either of two ways; either by manually cocking the hammer and then releasing it by trigger pressure, or by pulling through on the trigger so as to cock and release the hammer. Top

To fire the rifle without ammo, as in practice. Insure that no damage is done during dry-firing by using a snap cap to protect the firing pin, bolt face, etc. Top

Device, generally spring-loaded, which expels the cartridge or the fired cartridge case from the action after it has been extracted. Top

A claw-like device which removes the empty cartridge case from the chamber of a weapon and presents it to the ejector. Top

That portion of the operating cycle of a weapon in which the cartridge is removed from the ammunition supply and loaded into the chamber. Top

The expansion of a cartridge case, upon firing in the chamber, to a dimension different from the original. For example, a standard 30-30 round fired in the 30-30 Improved chamber expands the walls of the case so that they are much straighter, also creating a sharper shoulder. Top

Attachment to the muzzle of a weapon which cools the emergent propellant gas so that it does not cause flash or flame when meeting the outside air. Top

Muzzle attachment intended to conceal the muzzle flash from the firer when firing in poor light to maintain pupil dialation for night vision. It can also act as a flash eliminator but is not so efficient in this role. Top

(1) The spring-driven platform in a weapon magazine upon which the cartridges rest. (2) A spring or mechanically driven arm in the magazine of a clip-loaded weapon which forces the rounds up in the clip and presents them to the loading mechanism. Top

Removing material from the stock so that the barrel isn't touching any part of the gun except for the receiver. Top

The use of a synthetic substance to form a barrel channel and/or a seat in the stock for the action. New compounds are stronger than ever, and easier to use. Also good for repair and strengthening of specific areas of the stock. Top

Spiral cuts in the bore of a weapon which form the rifling and so impart spin t the cullet. The uncut portion between grooves are the ‘lands’. The number and form of the grooves, and the degree of curvature, depend on the weapon, the ammunition, and the designer’s preferences. Top

A delay in ignition. Unlike a misfire, the hangfire does go off; however, the rifle does not fire immediately. Associated primarily with muzzle-loaders, especially flint-locks, but can occur in a cartridge as well. Top

That distance as measured from the bolt face of the rifle to that point in the chamber where forward progress of the cartridge is halted. In a rimmed cartridge, this distance is taken from the bolt face to the end of the rim itself. In a belted magnum, the belt is used to gauge headspace. On a rimless cartridge, the shoulder is used to mark headspace distance. Gauges are used by the gunsmith to check the headspace in a rifle. These are Go and No-Go gauges, sometimes a "field gauge" as well. The Go gauge should allow the bolt to close down easily. The bold should not close on a No-Go gauge. It will close snugly on a field gauge. If the bolt of the action (and this applies to lever action, semiauto, and pump guns, as well as bolt-action rifles) will close on a No-Go gauge, that indicates excessive headspace and the condition must be corrected. Top

The vertical movement of a gun barrel at the instant of firing. It is related to the rigidity and mounting of the barrel and is not generated by recoil; it is a constant value for any given charge and projectile combination and can be compensated for in the sights. Top

Loss of bullet stabilization, causing the bullet to tumble end over end, all gyroscopic effect in keeping the bullet point-on having been dissipated. Top

The interior surface of a gun barrel between the grooves. Top

LEAD (pronounced ‘led’)
Metal used in the manufacture of small arms bullets and bullet cores. Usually mixed with a small amount of antimony to give the correct hardness. Top

A deposit of lead left in the rifling grooves of a firearm after prolonged firing of lead bullets. Eventually has a deleterious effect upon accuracy if not removed and is the reason for the adoption of jacketed compound bullets. Top

Term referring to a condition arising when the chamber of a revolver is not perfectly aligned behind the barrel. As the bullet passes from the chamber to the barrel, one side will strike the edge of the barrel which will ‘shave’ a thin layer of metal from the bullet. This affects balance and therefore accuracy; the metal shaving also tends to jam the revolver mechanism. Top

In modern terminology, the elapsed time from the release of the sear due to activation of the trigger to the actual impact of the firing pin upon the primer. A fast lock time is desirable. Top

A feed system for a firearm in which cartridges are stored in an integral or attachable carrier, from which they are fed into the weapon by spring or other agency. Top

MRT is the highest point in the parabola that the bullet reaches from muzzle to point of impact at the target. Since the bullet must arc upward from the muzzle in order to strike a distant target, it does climb above the line of sight. How high it must climb to reach a given distance is the MRT. Top

Specifically, one sixtieth of one degree, but for shooting purposes a minute of angel consists of an inch at 100 yards, two inches at 200 yards, three at 300, and so forth. A rifle capable of minute-of-angle accuracy will group its bullets into an inch center to center at 100 yards, two inches center to center at 200, three at 300, etc. Top

In the misfire, as opposed to the hangfire, the round does not go off at all after the trigger is pulled. Sometimes a dead primer is the cause. In muzzle-loaders, misfires often result from lack of flame reaching the main charge in the breech. Top

The front end of the gun barrel, from which the projectile emerges. Top

A device fitted to the muzzle of a weapon and designed to deflect some of the emergent gas and direct it against surfaces so as to produce a pull on the muzzle and thus reduce the recoil force. Not widely used on small arms, since the gas diverts sideways and increases the blast and noise level to the firer and his companions. Top

A device which generally slips onto the shaft of the cleaning rod, its function being to keep the rod centered in the rifle bore so that the rifling, especially at the muzzle, is not scraped. Top

The speed at which the bullet leaves the muzzle of the gun. Also referred to as ‘Vo’, the Velocity at zero distance from the weapon. Top

Expansion of the projectile in the bore due to reaction of gas pressure and inertia of the bullet. Also used to designate the expansion of the cartridge case as gases exert pressures which force the case to meet with the walls of the chamber. Also known as "bullet upset" in internal ballistics. Top

In reloading, the dent which appears in a cartridge case due to excessive lubrication being trapped between the case and the walls of the resize die. Top

A bullet which has a band between the rear and forward parts of the projectile. This band prevents mushrooming of the projectile past a given point. It also prevents separation of bullet core from bullet jacket upon impact and during penetration of the missile. Top

The deterioration of the metal of a rifle due to rust. Used rifles may have "pitted bores," meaning the bore is pockmarked with erosion caused by metal deterioration. Top

The body of a weapon; the casing inside which the bolt operates and to which the magazine and barrel are attached. Top

Rearward movement of the barrel or weapon due to reaction against the forward ejection of the bullet. Recoil is a phenomenon explained by Newton’s Third Law of Motion—every action has an opposite and equal reaction. If the rifle and the bullet were of the same mass, both would gain the same velocity after firing. Since the rifle is far heavier than the bullet, it is the bullet which speeds away from the rifle. However, the rifle does come back toward the shooter, "kicking" him. The attributes of recoil include, aside from rifle weight, the weight of the powder charge, weight of the bullet, and velocity of the bullet. Top

Spring in an automatic or self-loading weapon which cushions the rearward movement of the bolt and returns it to the forward position. Top

Spiral grooves cut into the interior of a gun barrel so as to spin the bullet and thus impart gyroscopic stabilization to it. The degree of curvature depends upon the weight and length of the bullet fired from the weapon. Top

A cartridge with priming mixture distributed around the rim of the case. The 22 rimfire is a good example. Top

The Sporting Arms and Ammunition Manufacturer’s Institute, an organization responsible for the standardization of measurements in the industry, including chamber dimension and other important specifications in shooting. Top

From the French, this term was used to denote a wooden shoe. In early shooting, the sabot was wooden. Today, the sabot is plastic. It is a heavy-duty device which fits around a bullet. Specifically, the sabot is used in modern ammo in order to fire a 22-caliber bullet from a 30-caliber bore. It can, and may, be used from many other calibers as well. Remington Accelerator 30-30, 308, and 30-06 caliber ammo uses the sabot, all three firing a 55-grain, 22-caliber bullet. The plastic sabot simply falls away from the bullet and the bullet speeds to the target. It is a good way of turning a larger-bore rifle into one capable of firing smaller projectiles. The above Accelerator for the 30-06 shoots a 55-grain, 22-caliber bullet at about 4,000 fps MV. Top

A bar or metal piece which translates the activation of the trigger into the dropping of the firing pin. The sear is disengaged by the trigger pull and then the hammer or plunger is allowed to fall, thus firing the rifle. Top

This is a ratio. It is the relationship between a bullet’s weight in pounds divided by the square of the bullet’s diameter in inches. The result is a number in decimal form. The higher the number, the greater the sectional density of the bullet. For example, a bullet of .226 sectional density compares poorly with a bullet of .286 sectional density, the latter handling the ravages of the atmosphere better, provided both bullets have similar profiles. Top

Descriptive of a weapon which, at the firer’s choice, can be set to fire single shots, automatic fire or specific-length burst, according to its mechanism. Top

A firearm which, for a single pressure of the trigger, fires a round and then reloads. The trigger must be released and pressed again to fire another round. Top

Weapon which fires one round, re-loads, and requires another pressure on the trigger to fire again. Synonymous with ‘self-loading’. Top

The distance between front sight and rear sight on a rifle wearing metallic sights. Open sights and aperture sights pertain. Top

Device attached to the barrel of a weapon and which traps the emergent gas and forces it to pass round a series of baffles, cooling it and thus reducing its volume, so that it emerges at low speed and does not, therefore, make much noise. The silencer also has holes bored in the gun barrel so as to bleed off propellant gas behind the bullet and reduced its speed to below that of sound, so avoiding a sonic crack due to the bullet’s flight. Top

A pointed bullet as opposed to a round- or flat-nosed bullet. Top

The channel in the bullet mold through which the molten lead is poured to form a projectile. Also the tiny projection of lead on the projectile left where the sprue plate cut the sprue away from the missile. This small projection is supposed to be loaded upward in the muzzle-loader for round-ball-shooting rifles. Top

Similar to a silencer insofar as it baffles the emergent gas, but does not bleed gas from behind the bullet. Therefore it only silences the muzzle discharge and not the bullet’s sonic wave. If used with subsonic ammunition is effectively a silencer. Top

Pistol-calibre selective-fire or automatic weapon, magazine fed, fired from the shoulder or hip, used for close-range combat. Top

Bullets, including round ball, made by forcing lead into a die which sizes the projectile—as opposed to creating bullets with a mold and molted lead. Round balls so created have no sprue. The round balls currently produced by Hornady and Speer are of the swaged type and are exceedingly uniform. Top

The arc described by the bullet from muzzle to destination. This arc is a parabola, a specific curve. The path the bullet takes is its trajectory. In sighting-in, the idea is to take best advantage of the bullet’s trajectory potential. Top

Effectively, an electrical means of calculating the pressure generated in the breech of the rifle. A specific quartz crystal is used. These crystals emit an electrical response to pressure. Pressure on the crystal results in more response for more pressure. A device transfers the chamber pressure to the crystal and a readout is translated into psi, pounds-per-square-inch pressure. Top

In rifle shooting, the speed of the projectile, measured in feet per second (fps). Derived from a chronograph. Top

The highest point of the bullet’s trajectory. Top

Adjustment of a weapon sight to right or left to compensate the effect of a cross-wind on the bullet. Horizontal movement of sights, as opposed to elevation. Also the space between the projectile and the bore in the muzzle-loader, which space is taken up by the patch. Top

That point at which the rifle is sighted-in to deliver its group. A rifle "zeroed" for 200 yards prints on the bull’s-eye at 200 yards. Zeroing is the adjustment of a weapon sight so that the bullet will strike the point of aim at some specified distance. Top