Action - The moving parts that allow you to load, fire and unload your shotgun (See Breech, Chamber, Trigger).

Barrel Selector - Determines which barrel of a double barrel gun will fire first.

Blacking/Blueing - The blue coloration applied to protect gun barrels.

Bore - In simple terms, the interior diameter of a gun barrel, which may vary according to the gun's design and intended use. The size of the bore is indicated by the term gauge.

Box-Lock - A type of gun action, often recognizeable by its squared appearance.

Breech - The end of the barrel nearest the stock.

Broken Gun - In a hinge type gun, where the barrels are dropped open and clear of the action, exposing the chambers to view.

Butt - The rear of the shoulder end of the gun's stock.

Comb - The side of the stock that fits against your cheek.

Chamber - The part of he action, at the breech end of the barrel, into which the shot shell is placed.

Choke - The degree of narrowing or constriction of the bore at the muzzle end of the barrel, intended to increase the effective range of the gun.

Ejector - The mechanism on shotguns by which spent shot cases are automatically ejected from the gun when it is opened after firing.

Forearm - The part of the stock that lies under the barrel.

Full Choke - The tightest constricting or narrowing of the bore, producing the greatest effective range.

Grip - The narrow portion of the stock held with the trigger hand.

Gauge - The term used to describe the interior diameter of the bore. The smaller the gauge number, the larger the bore size. Modern shotguns are available in 10, 12, 16, 20, and 28 gauge. An exception is the .410 bore shotgun, which is actually a 67 gauge.

Hinge - A type of action in which a hinge mechanism separates the barrel from the standing breech block, providing access to the chamber.

Improved Cylinder - Less constricted than a modified or full choke - a good all around choke for sporting clays.

Modified Choke - Moderate constriction or narrowing of the bore.

Muzzle - The end of the barrel from which the shot exits.

Over-and-Under - A two-barrelled shotgun with one barrel placed over the other (The American version of the standard British game shooting gun).

Pump - A type of action that loads and ejects shells by pumping the forearm of teh stock back and forth.

Recoil - The force with which the gun moves backwards into the shoulder when fired.

Safety - A safety device that, in the "on" position, prevents the gun from firing. In many field guns, the safety is immediately engaged when the gun is opened; in other guns, particularly competition grades, the safety must be manually engaged.

Semi-Automatic - A type of action in which gas from the burning gunpowder in the shell automatically ejects the spent shell and loads another. Semi-automatics are known for minimal recoil.

Shot - Round projectiles, usually of lead or steel. Depending on shot size and load, a shell can contain between 45 and 1,170 shot.

Shot Pattern - The concentration of shot measured in a circle at a given range, usually 30 to 40 yards.

Side-by-Side - A shotgun with two barrels sitting side by side. In Great Britain, the standard game shooting gun.

Stock - The "handle" of the shotgun, the part held to the shoulder, comprising the butt, comb, and grip.

Shotshell or Shell - The ammunition fired by shotguns, consisting of five components: The case, primer, powder charge, wad, and shot.

Trigger - Finger-pulled lever in single, double or trigger that drives the firing point forward and fires the gun.