Frequently Asked Questions > Terminology

There are a variety of terms that you will hear if you take up shooting. Below is a list of common words and a brief explanation of their meaning.

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Action : Used to describe the firearm's mechanism, by which it is loaded, locked, fired and unloaded. Screwed to the stock, it contains all the parts necessary to fire the cartridge, and to attach the barrels.

Air Gun : A gun that uses air or compressed gas to fire its projectile.

Anvil : Referring to primers. It is a fixed metallic point which the priming compound is crushed against when struck by the firing pin.

Automatic Ball Trap : Clay pigeon shooting discipline.

Ball : Projectile fired from muzzle loaders.

Ballistic co-efficient (BC) : This is a measurement of a body's ability to overcome air resistance in flight, a bullet with a high BC number will meet less air resistance than one with a lower number, and will therefore travel further.

Ballistics : The science that deals with the motion and behaviour of projectiles. Internal/ interior ballistics looks at the initial processes that accelerate the projectile, from primer ignition to the bullet exiting the barrel. External ballistics is the study of the projectile as it travels through the air. Terminal ballistics studies the interaction of the projectile with its target.

Barrel : Tube through which bullet is projected.

Battue : Type of Clay Pigeon. (See Shotguns).

Bedding : The way that the barrel and action are fixed to the stock.

Bench Rest : This refers to the use of a table or bench to support a gun. This is either when testing the gun's accuracy, or as a form of competition.

Berdan : Centre fire primer type. It can be recognised by having three off-centre flash holes. The anvil in a Berdan primer is part of the cartridge case. Berdan primed cases are not easily reloadable, and are found commonly in military ammunition.

Bipod : Attached to the fore-end of the rifle, a two legged support which is used mainly in long range rifle shooting.

Bird : Refers to clay target.

Black Powder : This is the oldest form of gun powder, used in muzzle loaders and early cartridges. It is a mixture of potassium nitrate (otherwise known as saltpetre), sulphur and charcoal.

Bolt : The bolt is used to push forward and extract the cartridge. Acting in line with the bore it locks the cartridge into place ready for firing. The bolt contains the firing pin and extractor.

Bore : This refers to the inside of the gun's barrel. Referring to rifled barrels it is the diameter of the barrel before the rifling has been cut. Additionally the term when referring to shotguns is used instead of Gauge.

Bore Sight : To roughly align the gun's sights with the target by looking through the bore of the barrel.

Boxer : Centre fire primer type. It has a large central flash hole. The anvil in a Boxer primer is part of the primer itself. Cases using these primers are easily reloaded.

Brass : Often used as a term to refer to empty cartridge cases.

Breech : The rear part of the gun's bore. This is the opening where the bullet is inserted into the the bore.

Breech Face : Part of the action which contacts the rear of the cartridge.

Breech Flag : Small flag inserted into the breech of the gun to show that it is not loaded.

Bull : Centre ring of a target. Usually the highest possible scoring shot.

Bullet : The missile that is fired from the gun.

Butt : The end of the rifle / shotgun stock.

Butt Plate : Protective plate on the butt.

Calibre : Refers to the diameter of either a projectile or the bore of a gun. It is the approximate bore/ groove diameter measured in hundredths of an inch. e.g. a 0.30 calibre gun has a bore diameter of approximately 0.30 inches.

Cap : A primer

Cartridge : The assembled round of ammunition containing case, propellant powder, primer, and projectile.

Case : This is the container that holds the components of a round of ammunition. There are various types of case.

Case Trimming : Removing metal at the mouth of a case to shorten it. (See "Reloading Rifle Ammunition" slide show in Multimedia).

Centre Fire : A metallic cartridge case with a central primer.

Chamber : Located at the breech end of the barrel this part of the gun accepts and supports the cartridge.

Choke : Used in a shotgun, these cause a constriction in the muzzle of the barrel's bore. This changes the spread of the shot, which in turn alters its pattern. Choke is measured in thousandths of an inch, and varies between 3 and 40 thousandths of an inch. Every thousandth is called a point of choke. A gun has a "full choke" of 40 points, (i.e. fullest constriction) "half choke" of 20 points, and no choke at approximately 3 points. Choke can be added at the production stage or after manufacture, with choke tubes.

Choke Tubes : These are screwed into the bore of the gun at the muzzle end, and are used to vary the choke of a shotgun.

Chronograph : Used to measure the muzzle velocity of a projectile.

Clay : Refers to the clay target shot at using a shotgun.

Cross hairs : Aiming mark on a telescopic sight. Consisting of two crossed lines perpendicular to each other.

De-burr : Removing burring around the mouth of a case. (See "Reloading Rifle Ammunition " slide show in Multimedia).

De-cap / De-prime : Removing the primer from a case. (See "Reloading Rifle Ammunition" slide show in Multimedia).

Die : A tool used in loading ammunition, either to reform cases, or to seat bullets. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Down-the-line (DTL) : Clay pigeon shooting discipline. (See Shotguns).

Drag : Air Resistance

Drift : Referring to the effect of bullet spin / rotation causing a projectile to deviate from its path.

Drop : The distance a projectile falls due to gravity as it travels down range.

Ear Defenders : Prevent damage to hearing while shooting or on a shooting range.

Elevation : Vertical adjustment of the sights to cause the bullet to hit the desired target. (See "Approximate Wind Allowances & Elevation" slide show in Multimedia).

Firing Pin : Part of the gun that strikes the primer.

Flash Hole : Hole between the primer pocket, and the body of the cartridge case.

Flintlock : Type of mechanism used in a muzzle-loading rifle, which is fired by the striking of a hammer carrying a piece of flint upon a frizzen. This in turn causes sparks to hit the pan below, primed with gunpowder. THis ignites the powder within the barrel which in turn fires the projectile. It was developed in the early 17th Century, and superceded the wheel-lock.

Fore-end : Also known as the forearm, this is the part of the rifle's stock, which extends under the barrel, and forward of the receiver.

Full Metal Jacket (FMJ) : Bullet type where the core is cased in jacket material, apart for an opening on its base.

Free Bore : The distance the bullet travels upon firing before it engages with the rifling.

Frizzen : Strike plate for the flint attached to the hammer of a flintlock rifle.

Fullbore : Refers to any type of firearm that is not smallbore. Fullbore firearms use a centre-fire cartridge.

Gauge : Size of a shotgun bore. The way of determining this is the number of spherical pure lead balls the same diameter as the barrel's bore, that weigh one pound. e.g. a 20 bore gun will need the weight of 20 lead balls per pound. If the bore is less than 32 it is measured in decimals of an inch.

Gauge In : Refers to scoring targets. If a bullet breaks the line divining the scoring rings, the higher score is taken.

Gauge Out : Refers to scoring targets. If a bullet breaks the line divining the scoring rings, the lower score is taken. Usually used in smallbore prone shooting.

Grain : Measure of powder - 7000 grains equal one pound, 437.5 grains equal one ounce.

Granulation : A reference to powder grain size and type.

Grooves : Rifling in a barrel.

Group : The pattern made on a target by the bullets fired at it. This is usually measured centre to centre of the holes furthest apart.

Gun Powder : Substance used as a propellant. This can refer to either smokeless powder or blackpowder.

Hand loading : Reloading ammunition by hand. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Hangfire : A delayed firing after pulling the trigger.

Head space : Distance between the closed breech face and the part of the gun's barrel/ chamber preventing the cartridge from moving forwards.

Holdover : Vertical distance that the shooter must aim above the target to obtain a hit when the range is further than the gun's scope allows.

Hollow point : a hole in the tip of the bullet.

Jacket : "Skin" of a bullet.

Keyhole : Elongated bullet imprint on a target- this shows that the bullet did not hit the target point-on.

Leading : Deposits of lead in the bore of the gun, this is a form of metal fouling.

Lever Action : This is a rifle action, where rather than pulling the bolt back to cock the gun and feed the cartridge, the breech bolt and carrier are operated by a finger lever trigger guard.

Line of Departure : Straight line with which the bullet leaves the rifle barrel, equal to the axis of the bore extended into space. Gravity means that the bullet does not follow this imaginary line.

Line of Sight : Straight line from the sights to the point of aim.

Locking Lugs : A feature which prevents the bolt from moving, using protrusions to engage with the receiver when the bolt is closed.

Lubricant : Case sizing lubricant reduces friction when sizing cartridge cases. Bullet lubricant helps reduce leading. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Magnum : Refers to a cartridge of high power or size.

Magazine : Container which holds cartridges, that can be inserted into a firearm for continual feeding of the ammunition into the chamber.

Martini Action : Type of rifle action.

Matchlock : Type of mechanism used in a muzzle-loading rifle, which is fired by the lowering of a slow-burning wick into a hole in the breech of the rifle, which ignites the charge in the pan, which in turn ignites the powder within the barrel, and fire the projectile. It was developed in the late 14th Century.

Metal Fouling : Deposits of metal from jacketed bullets in the bore of the gun.

Midi : Type of Clay Pigeon. (See Shotguns).

Mini : Type of Clay Pigeon. (See Shotguns).

Minute of Angle (MOA) : This is a measurement of angle which equates to 1/60th of a degree. It has the effect of moving the sight pattern approximately 1 inch every 100 yards of distance.

Misfire : Failure of cartridge to discharge.

Musket : A muzzle-loaded, smooth-bore long barrelled gun, fired from the shoulder.

Muzzle : Front end of barrel, point projectile leaves barrel.

Muzzle Blast : Compression of air caused by high power, hot powder gases venting from the muzzle.

Muzzle Brake : Fitted to a muzzle to deflect gases exiting the bore. It is used to reduce recoil by redirecting the muzzle blast.

Muzzle Loader : This is the term used to describe firearms which load from the muzzle end of a gun, for example black powder pistols or rifles (flintlocks, matchlocks etc). Muzzle loaders usually have rifled barrels.

Neck : Part of case that grips the bullet. With bottleneck cartridges this is the section forward of the shoulder.

Neck Down / Neck Up : Resizing the neck of the case during reloading. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Neck Expansion : Expanding the neck of a sized case. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Neck Size : Resizing the neck of a case whilst leaving the body unchanged. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Nipple : In blackpowder pistols or rifles, the nipple is a duct between the percussion cap and the powder within the chamber.

Olympic Trap : Clay pigeon shooting discipline.

Over-and-under : Refers to a type of shotgun where the barrels are adjacent vertically.

Pan : Refers to Muzzle loading firearms, the pan contains the charge of blackpowder that is ignited and in turn ignites the powder in the barrel, which fires the projectile.

Parallax : Occurring in telescopic sights parallax occurs when the image viewed through the lens does not lie exactly on the same plane as the cross hairs (reticule).

Patching : Covering bullet holes in target with adhesive circles to make the target re-useable.

Pattern : Generally used to refer to shotguns and refers to the spread of the cartridge load. (It is considered to be the number of shot pellets found in a circle of diameter 30 inches, using a 12 bore shotgun and firing a cartridge loaded with 1 1/10 ounces of Number 6 shot, and 33 grains of smokeless diamond powder, shot from a distance of 40 yards).

Plinking : Common term for casual non-competitive shooting at a target.

Powder: Ballistic chemical which is used to propel a projectile.

Powder Measure : A device that meters powder charges - used in reloading. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Powder Scale : Used for measuring the correct weight of powder used to reload cartridges. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Powder Trickler : An accessory that allows the measured powder to "trickle" a few grains at a time into the cartridge case. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Primer : A small metallic cup containing an amount of detonating ("priming") mixture used to ignite the propellant.

Primer Pocket : Space into which the primer fits on a centre fire cartridge. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Primer Punch : Tool to insert/ seat the primer. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Progressive Reloading Press : Reloading press where pulling the press handle will cause several different stages of reloading to take place simultaneously. This speeds up the reloading process. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Projectile : A bullet or object projected by force which continues in motion by its own inertia.

Prone: Shooting position whereby the shooter is laying down.

Propellant : The correct term for "Powder"; a ballistic chemical which is used to propel a projectile.

Pyrodex (R) : Brand name of a black powder replacement.

Rabbit : Type of clay pigeon. (See Shotguns).

Ramrod : Used to push the bullet fully down the bore of a muzzle loader.

Range : i) Place at which shooting is conducted. ii) The horizontal distance which the projectile travels - from gun to target.

Ream : The act of removing metal from a cavity by cutting with a rotary tool.

Receiver : The part of the firearm housing its operating parts.

Recoil : The backwards "kick" of the gun upon firing. This is caused by the gases pushing the projectile through the barrel and the jetting of these gases.

Reloading Press : Used in reloading cartridges. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Reticule : Aiming mark on a telescopic sight. Often cross hairs.

Rifling : Spiral grooves cut within the bore of a gun that causes the bullet to spin which in turn ensures that it flies with stability to the target. Also known as grooves.

Rim : Feature at the base of the cartridge which allows it to be easily extracted from the gun. (Also known as the Flange).

Rimfire : Cartridges which have the priming component at their base, not within a separate primer. the striker therefore does not have to hit the centre of the cartridge for it to explode. This is seen in smallbore (.22) rifle ammunition, and is not practically reloadable. (See Technical Diagrams).

Round : Term referring to one cartridge.

Round Nose : Referring to the shape of a bullet with a blunt spherical nose.

Seating Depth : Referring to the distance that the bullet in a cartridge sits below the mouth of the case.

Sectional Density : The weight of a bullet in pounds, divided by the square of its diameter in inches.

Semi - Automatic : Gun which is self loading from magazine. It is not necessary to manually feed the cartridge in after each shot as with a bolt-action, or with an over-and- under or side-by-side shotgun.

Shock Wave : This refers to a compression wave which is formed whenever the speed of a projectile relative to air or other medium is in excess of that at which the medium is able to transmit sound.

Shot : Small balls which are found in shotgun cartridges. These vary in size depending on the cartridges.

Shoulder : Refers to the sloping part of a bottle neck cartridge case that is between the body and the neck.

Side-by-side : Refers to a type of shotgun where the barrels are adjacent horizontally.

Sighting In : Setting up the sights on a gun.

Single Stage Reloading Press : Differs from a Progressive Reloading Press, as it only does one stage of the reloading at a time. Changing dies in the press will allow it to do other processes.

Sizing : Resizing a used cartridge case to ensure that it fits into the chamber of the gun. Bullets can also be sized by using a die and press. (See "Reloading Rifle Ammunition " slide show in Multimedia).

Skeet Shooting: Clay pigeon shooting discipline. (See Shotguns).

Sling : Strap support used with rifles.

Slug : A large single projectile. Used in shotguns, mainly for the purpose of hunting large game. (Also used as a slang term for a bullet).

Smallbore : Basically refers to .22 rimfire shooting.

Smokeless Powder : A nitrocellulose-based propellant. It is called "smokeless" as it produced much less smoke than the older black powder.

Snap Caps : Dummy cartridges with spring-loaded "primers". Usually found used with shotguns. The snap cap is intended to absorb the shock to the components when testing the firing mechanism, as dry firing can damage the gun's parts.

Spent : Fired / used cartridge.

Spin : The rotation of the projectile due to the rifling of the bore.

Spotting Disc : Used to mark targets at long range where the shot holes can not be seen. A brightly coloured marker is put in the hole in the target.

Spotting Scope : Telescopic lens used to see the and target.

Sporting Clay Pigeon Shooting : Discipline of clay shooting where the clays are variable. (See Shotguns).

Stabilise : The rotation of a bullet about its long axis to ensure it flies point-on (nose first).

Stock : The part of the rifle / shotgun which attaches the action, barrel, trigger etc.

Stripper Clip : Term for a device that holds several rounds of ammunition together in a single unit for easy loading. When the ammunition is loaded into the gun, the clip is "stripped" away.

Swage : Forming the desired size / shape by forcing through or into a die.

Throat : Part of the bore in front of the chamber, which tapers to the start of the rifling.

Trajectory : Path of the projectile in flight.

Trap : Device which throws clay pigeons.

Twist : This refers to the angle of the rifling in relation to the axis of the bore. This is usually measured by the length of barrel needed to rotate a bullet one complete turn. E.g. if a barrel is rifled with a 1 in 12" it takes 12 inches of barrel length to rotate the bullet once. If this is 1 in 10" it takes 10 inches etc. As such the 1 in 10" barrel has a "faster" twist rate as the bullet spins faster in this barrel. The smaller the second number the faster the bullet is spinning.

Velocity : Speed of the projectile.

Wad : Used mostly in reference to shotgun cartridges this is a disc made of of paper, felt, plastic etc. to separate the powder from the shot, and also to help hold the charge of shot together on its passage along the barrel.

Wad cutter : Type of bullet (or air gun pellet) that cuts a clean round hole in the target.

Wheel-Lock : Type of mechanism used in a muzzle-loading rifle, which is fired by sparks produced by holding pyrite against a rapidly revolving serrated wheel, which would in turn ignite the charge in the pan, which in turn would ignite the powder within the barrel, and fire the projectile. The wheel lock was a development of the early 16th C, and superceded the matchlock.

 

Wind Deflection / Drift : The change in the path of the bullet, to the left or right, caused by the wind.

Windage : The amount of sight correction- left or right- required to compensate for wind deflection. (See "Approximate Wind Allowances & Elevation" slide show in Multimedia).

Wind Flags : Flags by which the direction and the strength of wind can be estimated. Mostly useful for fullbore shooting.

Yaw : Upon leaving the barrel a bullet will often tip on its axis at a slight angle. The bullet's spin however should stabilise this fairly quickly. However, if the bullet travels too slowly, or at an insufficient twist rate it may not stabilise and can end up "tumbling".

Zero / Zero Sight Adjustment : This refers to the adjustment of a gun's sights in order to place a shot at the desired impact point on a certain range, using certain ammunition and with the absence of wind. It is from his setting that later adjustments are made with varying distance / ammunition and wind.

Zero Range : The distance at which the bullet path exactly coincides with the line of sight.

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