Letter: G

1. In handguns, the handle. 2. In shoulder arms, that portion of the stock to the rear of the trigger.

1. A unit of weight (avoirdupois), 7000 grains per pound. The grain unit is commonly used in American and English ammunition practice to measure the weight of components. 2. A term sometimes applied to a single particle of propellant powder. More properly called a kernel or granule.

Barrel rifling in which the rate of twist is faster at the muzzle than at the chamber end.

The application of a mixture of fiberglass and resin between the action and/or barrel and stock.

A copper alloy with a nominal composition of 95 percent copper and 5 percent zinc. “Gilding Metal” is the trade name for the Copper Development Association, Inc. Alloy C21000. It is extensively, but not exclusively used in the manufacture of bullet jackets. See also “Commercial Bronze.”

1. A term used in the identification of most shotgun bores. (410 bore is an exception.) It is related to the number of bore diameter lead balls weighing one pound. 2. An instrument for measuring or testing a parameter.

1. Any hole in the action of a firearm to allow the escape of gases from the breech. 2. A hole in the gas cylinder of a firearm to bleed off gas. 3. Ammunition: See Flash Hole. 4. See Barrel Vent.

An opening in the wall of a barrel or chamber to allow the redirection of propellant gas. Usually associated with gas-operated actions or other mechanisms.

The component in a gas-operated firearm upon which the propellant combustion gas impinge to operate the action.

An automatic or semiautomatic type firearm in which the propellant gases are used to unlock the breech bolt and then to complete the cycle of extraction and ejection. This is accomplished usually in conjunction with a spring which returns the operating parts to battery.