Effective Motion - a mechanism - the breech action of a firearm. The operating part that transmits power to the mechanism.

Ammunition is the consumable component of firearms system. Ammunition is required to fire a firearm. A single unit of ammunition in modern firearms is called a cartridge. The units of measure for quantity of ammunition are rounds. There are hundreds of sizes of ammunition; examples include .223 Remington, 9mm Luger, 30.06, .308 Winchester, .300 Winchester Magnums, and .50 Browning Machine Gun (BMG). The ammunition used must match the firearm.

A narrow hollow cylinder portion of a firearm through which the bullet travels during the acceleration phase of its journey to the target.

The mechanism of some firearms that holds the cartridge in place during the firing process. See also Bolt Action.

Bolt Action
A type of firearm, almost always a rifle, in which an empty shell casing (remnant of a cartridge) is removed from the firing chamber by the turning and retraction of a metal cylinder shaped mechanism called a bolt. A new, unfired, cartridge is inserted and secured into the chamber by reversing the action of the bolt. Bolt action firearms are typically the most accurate.

The hollow portion of a barrel through which the bullet travels during its acceleration phase.

The metal block at the base of the breech which retains the cartridge after it has entered the chamber. The bolt of a bolt action rifle is a breech-block.

A generally cylindrical shaped projectile that travels through the air after being fired from a firearm. This is only one component of a cartridge, which is a single piece of ammunition.

Butt (of a stock)
The stock of a rifle or shotgun is usually placed against the shoulder to fire. The contact point with the shoulder is the butt of the firearm.

A target range. An obstacle behind a target for stopping a shot. (

The portion of a barrel where a cartridge is placed just prior to being fired. This is a high-pressure containment area that is very precisely aligned with the bore of the barrel. A firearm cannot be fired when the chamber is empty.

The assembly of a bullet, shell casing, gunpowder, and primer that is put in the chamber of a firearm.

1) The diameter of the bore of a firearm. Typically in millimetres or a decimal fraction of an inch. 2) Common usage, but imprecise -- the name of the cartridge used in a firearm. Examples include .223 Remington, 220 Swift, 22-250 which all use the same bullet, but different cartridge, because they have the same diameter of bore.

Centrefire Cartridge
A cartridge that has a primer located in the centre of the base of the shell casing. This is as opposed to a rimfire cartridge.

In cartridge making, to fold the edge of (a cartridge case) inward so as to close the mouth partly and confine the charge. (

A state of readiness of a firearm. The hammer (or similar mechanism if there is no hammer) only needs to be released by the trigger to cause the firearm to fire.

A usually round pin (often wood) that fits tightly into a corresponding hole to fasten or align two adjacent pieces. (

1) The setting on the sights of a firearm that controls the vertical placement. 2) The altitude above mean sea level. This is important for  long range precision shooting because the air density changes with elevation and affects the path of the bullet.

A firearm which uses the combustion of some chemical mix, typically smokeless gunpowder, to propel a projectile (see the definition at the beginning of this manual).

Firing Line
A line, either imaginary or marked, from which people shoot their firearms down range.

Firing Pin
A needle-like metal part of a modern firearm that gives a vigorous strike to the primer initiating the firing of the cartridge.

Flush Game
To frighten from cover. To drive or force into the open. To excite, to animate. To stir. See also Game. (

Game animals are any kind or taxon of wildlife declared to be game by the Wildlife Act 1975

A chemical mixture or compound that burns rapidly with or without the presence of air to produce hot pressurised gases capable of propelling a bullet. There are two basic types of gunpowder - Black Powder and Smokeless Powder. Black Powder is composed of a mixture of charcoal, sulphur, and potassium nitrate and produces a cloud of white noxious smoke when it burns. Smokeless Powder burns much cleaner but may still produce a small puff of smoke. All modern firearms use smokeless powder, not only because there is less smoke, but also because the bullets can be made to exit the firearm faster. Hammer
Similar in function to the carpenter and mechanic’s tool, the hammer of a firearm is propelled by a spring to strike either directly or via a firing pin the primer of a cartridge causing the firearm to fire.

Heel (of a stock)
The top of the butt, when the firearm is in position on the shoulder to be fired, is called the heel.

Iron Sights
Sights made of metal with no optics.

Lever Action
A type of firearm that uses a lever operated mechanism to remove an empty shell casing and insert a new cartridge in the chamber of a rifle. Other types of mechanisms include bolt action and pump action.

An ammunition feeding device that holds the cartridges just prior to them being put in the chamber of the firearm by the operation of a mechanism on the firearm. This mechanism may be operated manually as in a bolt action or semi-automatically when the firearm fires after pulling the trigger. The magazine may be detachable or part of the firearm (as in a tubular magazine common with lever action rifles and most semi-auto and pump shotguns).

The end of the barrel where the bullet exits as it is being fired.

A bullet or piece of small shot. (

A small metal cup that contains a tiny explosive charge that is sensitive to impact. A primer is placed in the base of a shell casing to ignite the powder of the completed cartridge. It is detonated by the striking of a firing pin in the firearm.

An object given an initial velocity which proceeds on its own inertia through the air and perhaps solid objects in its path. A bullet fired from a firearm is a projectile.

Pistol Grip
1) A section of a rifle stock shaped like the grip of a pistol.
2) A variation of stock type that is often fitted to military-type firearms, and is not permitted on a sporting semi-automatic firearm.

See gunpowder.

Pump or Pump Action
A type of mechanism for removing a spent shell casing from the chamber of a firearm and inserting a fresh cartridge into the chamber. This type of mechanism is most commonly used in shotguns and rimfire rifles.

A rod used to force the charge into a muzzle-loading firearm. A rod used to clean the barrel of a firearm. (

The portion of a rifle that has the serial number on it. The stock, barrel and other components such as the bolt are typically attached to the receiver. Some firearms may have a multi-part receiver such as an upper receiver and a lower receiver.

The sudden rearward push made against the shooter when a firearm is fired. This push is due to Newton’s Third Law of Physics (for every action there is an equal and opposite reaction). The heavier the bullet and the faster it leaves the muzzle of the barrel the more recoil. The weight of the powder and the velocity of the gases it produces at the muzzle also enter into the equation describing the total recoil.

A firearm designed to be fired from the shoulder and fire only a single projectile at a time, as opposed to a shotgun, which can throw many small projectiles (shot) at the same time.

Rimfire Cartridge
A type of cartridge whose primer is integral to the shell casing and located along the edge of the base in a rim. When the firing pin strikes it pinches the rim against the chamber and causes it to detonate and ignite the powder.

A unit of measure for ammunition. One cartridge. Typical quantities are 20 rounds and 50 rounds in single box. A serious target shooter will normally go through about 100 rounds in one day. At some pistol matches a shooter may go through several hundred rounds. In a weekend of training, a pistol shooter may go through 1500 or more rounds.

Safety (mechanical)
A mechanical device used to block the firing pin or trigger such that the firearm cannot be fired.

Self Loading
A firearm that uses the energy and momentum of the just fired cartridge to eject the spent shell casing and load a new cartridge into the chamber. This is an automatic loader. This is sometimes shortened to ‘automatic’ which some confuse with a full-auto (machine gun).

1) n. A term used to describe the round pellet projectiles fired in a shotgun. The shot may be one of many different sizes described by a number. The smaller the number the larger the pellet. The numbers do not go negative, but start adding additional zeros to the designator. 00 (pronounced ‘double-nought’) is larger than 0. Number 8 shot is about the size of a head of a pin. 00 shot (also sometimes called ‘buckshot’) is about the size of a large pea. 2) v. Act of firing a firearm.

A (typically) smooth bore long firearm that shoots a group of pellets called shot instead of bullets. Depending on the bore size and the size of the pellets there may be from less than 10 to two hundred or more pellets in a single shotgun cartridge. Shotguns are designed for shooting moving targets (such as flying birds or moving rabbits) at close range.

Shell Casing
A hollow, bottle or drinking glass shaped, piece of metal that is closed on one end except for a small hole which holds a primer. The open end holds the bullet. The hollow portion holds the powder. Together the assembled unit is called a cartridge.

The device that aids the eye in aiming the barrel of a firearm in the proper direction to hit a target. The most common sights are iron and telescopic.

To move threateningly or menacingly. To track prey or quarry. To pursue by tracking stealthily. To approach under cover of a screen, or by stealth, for the purpose of killing, as game. (

The supporting structure of a long firearm to which the receiver, barrel, trigger, and other components are attached. Typically this is the portion of the firearm the shooter holds while firing. See also heel and butt.

Telescopic Sight
A sight which has an integral telescope.

Toxic Shot
As determined in Wildlife (game) Regulation 2001.

The mechanism used by the shooter to initiate the firing of a cartridge. Typically this is a lever type piece of metal that must be pulled with the index finger.

Trigger Lock
A locking device put on a firearm to render it unable to be fired.

Trigger Pull
A piece, as a lever, which is connected with a catch as a means of releasing it; especially (Firearms), the part of a lock which is moved by the finger to release the cock and discharge the piece. (