Action

the moving parts that allow you to load, fire and unload your shotgun.

Barrel Selector

determines which barrel of a double barrel gun you will fire first.

Blacking/Blueing

the blue coloration applied to protect gun barrels.

Bore

the interior diameter of a gun barrel, which will vary according to the gun's size and intended use.

Box-Lock

a type of gun action, often recognizable by its squared appearance.

Breech

the end of the barrel nearest to the stock.

Break Open

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 the 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 constriction 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.

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

least constricted or narrowed choke causing shot pattern to widen relatively quickly.

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 barreled shotgun with one barrel placed over the other.

Pump

a type of action that loads and ejects shells by "pumping" the forearm of the stock back and forth.

Safety

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

Semi Automatic

a type of action in which gas from a burning gunpowder in the shell automatically ejects the spent shell that loads another.

Shot

round projectiles, usually of lead or steel.

Shot Pattern

the concentration of a 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.

Stock

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

Shell or Shotshell

the ammunition fired by shotguns, consisting of five components: the case, primer, powder charge, wad, and shot.

Trigger

finger-pulled lever (single, double, or release) that drives the firing point forward and fires the gun.

Source: Black's Wing & Clay