GUARD SCREW

A screw that extends from the trigger guard into and through the stock.

GUN COTTON

Nitrated cellulose (either cotton linters, wood pulp or a mixture of the two) which is used for the manufacture of smokeless propellant. Chemical name – nitrocellulose.

GUN POWDER

A commonly used term for cartridge and muzzle loading propellant.

GUN ROOM

A room that is maintained for the purpose of keeping guns in storage, on display, or for repair.

GRIP ADAPTER

A filler piece attached to the front of the grip of a firearm.

GRIP SAFETY

An auxiliary device on the grip of some handguns which is intended to prevent firing until depressed.

GAIN TWIST

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

GROOVE DIAMETER

The major diameter in a barrel which is the diameter of a circle circumscribed by the bottom of the grooves in a rifled barrel.

GAS CHECK

1. A metallic cup attached to the base of some lead alloy bullets. 2. An obturating cup used under the piston in crusher pressure testing.

GROUP

A series of consecutive shots fired at the same aiming point without changing the sight adjustments of the firearm.