Letter A

The Definition of AD

Arsenal Exchange - Firearms Classifieds - Industry Directory

AD

Abbreviation for Accidental Discharge


19 Other Firearms Definitions You Need To Know


Pepperbox

An early form of muzzle-loading revolver wherein, instead of the current practice of having one barrel mated to a multi-chambered rotating cylinder, multiple joined barrels revolve together around a central axis.

Point of Impact

The point where the projectile from a firearm hits.

Hook

A concave, semi-cylindrical surface cut into the forward lump of a barrel set of a break-open firearm which revolves about the hinge-pin when the gun is opened.

Slide Lock

A slang term for slide catch.

FOPA

Firearm Owners' Protection Act of 1986. It is a United States federal law that revised many provisions of the Gun Control Act of 1968. It bans civilian ownership of machine guns manufactured after May 19, 1986. Firearms made and registered before that date are not affected. The law limits the Bureau of Alcohol, Tobacco and Firearms from inspecting gun dealers more than once a year, with follow-up inspections allowed only The law also specifically forbids the government from creating a national registry of gun ownership.

Annulus

A tiny circular recess at the base of a cartridge case surrounding the primer pocket. Recoil from fired cartridges invariably impress a discernable ring on the breech or bolt face of a firearm, providing some evidence of the amount of use it has seen.

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.

Magazine Follower

Same as Follower. A plate, mounted to the top of a spring, inside a magazine, over which cartridges may slide smoothly as they are guided into the chamber of a repeating firearm.

Boattail

The tapered rear end of a bullet. This design is used to increase ballistic efficiency at long range.

Martini

A hammerless single shot action type whereby a breech-block, hinged at the upper rear, operated by an underlever, tilts downward to expose the chamber.

Keyhole

The tendency of a bullet to tip in flight and hit a target sideways, leaving a distinctly oblong hole. This destabilization of the spinning bullet in flight is typically caused by a bullet weight inappropriate for the rate of twist of the rifled barrel, an out-of-balance bullet or its having nicked an impediment such as a blade of grass, in flight.

Field Gun

A shotgun, generally stocked to shoot where it is pointed and of relatively light weight because one often carries it a great distance for upland birds, the consequent recoil not being an important factor because one actually shoots it very little.

Bore Diameter

The measurement from one side of the bore to the other. In a rifled barrel this means measurement of the bore before the rifling grooves are cut.

Rifle

A shoulder-fired long gun which has a rifled barrel.

Bedding

That part of the stock on a rifle or shotgun into which the barrel fits.

Cable Lock

A cable with a padlock at the end. It is threaded through the action of the firearm rendering the gun safe and useless until the lock is removed.

Forend

One of the three major dismountable components of a break-open gun (the others being the barrel(s) and the action/buttstock) which secures the barrels to the receiver, often houses the ejector mechanism, and for some, provides a handle for the one's secondary hand.

Hand-Detachable Locks

The firing mechanism of a break-open gun which may be removed for inspection or cleaning without the use of tools. The release latch may be plainly visible or concealed. A feature typically seen on sidelock guns but also on the Westley Richards "droplock" boxlock action.

Benchrest

A device used (usually set on a counter) to support a shooters arms and/or hands to help make steadier shots.