Letter G Firearms Glossary

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Gain Twist

A form of rifling where the helical angle (pitch) sharpens progressively down the bore in the interest of maximizing the bullets ultimate rotational speed by initiating it slowly.

GAP

Abbreviation for Glock Auto Pistol

Gape

The degree to which the barrel(s) of a break-open gun drop down; the size of the opening space, which should be sufficient to allow for ease of loading, unloading and properly-functioning ejection. A good gape is easier to achieve on a side-by-side than an over & under where the bottom barrel is well-enclosed by the action body.

Garniture

A deluxe set of several different associated weapons, being any combination of rifle, shotgun, various handguns, and possibly a knife or two, cased together with appropriate cleaning and loading tools.

Gas Check

A metal cup placed on the end of a lead bullet to protect the lead against the hot gases of the burning powder charge. Used in some types of firearms ammunition when non-jacketed bullets are used in high pressure cartridges, to prevent the buildup of lead in the barrel and aid in accuracy.

Gas Operated

The superheated air created by burning powder. A gas-operated firearm is one that uses the energy from these superheated gases to work the action in semi-automatic and automatic guns.

Gas Port

A small hole in the barrel of a gas-operated firearm through which expanding gases escape to power the autoloading system.

Gas Vent

A passage built into a firearm to allow the safe conduct of unexpected gas, as from a pierced primer, to minimize damage both to the gun and to the shooter.

Gauge

System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight equals one pound. The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.) The Gauge/Bore system is also used, by convention, to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel rifles.

GCA

Gun Control Act of 1968. It is a U.S. federal law that regulates the firearms industry and firearms owners. It primarily focuses on regulating interstate commerce in firearms by generally prohibiting interstate firearms transfers except among licensed manufacturers, dealers and importers. It also prohibits all convicted felons, drug users and the mentally ill from buying guns amd raised the age to purchase handguns from a federally licensed dealer to 21.

Ghost-Ring Sight

A type of aperture rear sight with a large opening and a thin rim that seems to fade out when the shooter looks through it. Sometimes installed on rifles and shotguns intended for home defense or police use.

Gloaming Sight

A second, folding or pop-up front sight bead of larger than usual size, perhaps not as accurate as a normal fine bead, but easier to see in the gloaming (twilight) or dawn.

Globe Sight

A front sight assembly, primarily for target rifles, consisting of a tube, housing interchangeable beads and blades. The tube guards against imperfect aiming due to sight pictures influenced by reflections.

Glock

The Glock pistol, sometimes referred to by the manufacturer as a Glock "Safe Action" Pistol, is a series of polymer-framed, short recoil operated, locked breech semi-automatic pistols designed and produced by Glock Ges.m.b.H., located in Deutsch-Wagram, Austria.

Glock Auto Pistol

A type of .45 caliber ammunition designed in 2002 by Ernest Durham for use in the Glock Model 37.

Grain

A unit of weight widely used to express the weight of bullets and of powder charges. Equal to 1/7000 pound.

Grip

The portion of the stock (on a rifle) or frame (on a pistol) gripped by the trigger hand.

Grip Panels

The interchangeable surfaces that are installed on the part of the gun that you hold. Users change grip panels to improve the look or feel of the firearm, or to personalize it so that the gun is more suited to a different hand size. Some grip panels are chosen for function, while others are chosen for looks. Common grip-panel materials are wood, plastic, and rubber.

Grip Safety

A passive, external safety typically located on the backstrap, which must be fully depressed to release the trigger. Most 1911-pattern pistols feature a grip safety.

Grooves

The cut-away, concave portions of the rifling inside the barrel of a firearm discharging a single projectile.In other words, the lower portion of rifling.

Group

A set of holes in a target left by a succession of bullets fired from the same rifle or handgun, using the same ammunition and sight setting. Fired (within the limits of one's marksmanship ability) to determine the inherent accuracy of the rifle/ammunition combination, and to aid in the proper adjustment of the sights.

Gun

A firearm.

Gunpowder

Also called black powder, gunpowder is a mixture of sulfur, charcoal, and potassium nitrate. It burns rapidly, producing a volume of hot gas made up of carbon dioxide, water, and nitrogen, and a solid residue of potassium sulfide. Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. The term gunpowder also refers broadly to any propellant powder. Modern firearms do not use the traditional gunpowder (black powder) described here, but instead use smokeless powder.