Letter G

The Definition of GAP

Arsenal Exchange - Firearms Classifieds - Industry Directory

19 Other Firearms Definitions You Need To Know


Overbore Capacity

Is that combination of caliber, barrel length, bullet weight, and case volume which does not allow the complete burning of the charge of ballistically correct powder within the volume of case and barrel.

Pinfire

An early form of complete, self-contained cartridge. It included bullet, powder and ignition primer, all in one package. The primer was located towards the base of the cartridge, but completely internally. The pin, shaped like a little finishing nail, pointed on the inside end and resting on the internal primer, projected radially about a quarter-inch to the outside of the base of the cartridge. When loaded, a pinfire gun showed the tips of the pins exposed through small slots in the tops of the breech faces of the barrels. To fire, hammers fell on the pins, driving them (through the wall of the cartridge) into the internal primer.

X-Frame

The frame designation that Smith and Wesson uses for their extra large framed revolvers like the S&W Model 500 and S&W 460XVR

Delayed Blowback

A self-loading firearm whose breechblock and barrel are not positively locked together, but which incorporates a mechanism which initially restricts the breechblock from moving when fired, delaying its opening.

Minute Of Angle

A 1/60th part of a degree, the unit of measure used in adjusting rifle sights. As it turns out conveniently, a minute of angle translates almost exactly to one inch at 100 yards (actually 1.047 inches), to two inches at 200 yards and three inches at 300 yards

DAO

Abbreviation for Double Action Only. Is a type of firearm in which the firing mechanism cannot be cocked in a single-action stage. Firing always occurs as a double-action sequence where pulling the trigger both cocks and then fires the gun.

Follow Through

Holding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.

Mortar

An artillery piece used to fire shells over short ranges at very high trajectories.

Headstamp

Markings impressed into the base of a cartridge case, normally identifying the maker's name, the cartridge calibre designation, and sometimes the date.

Cold Clean Bore

The first shot from a rifle that has been cleaned, and not fired recently may go to a different point of impact, for the same point of aim than a rifle that has been fired recently. This first shot is referred to as a shot from a cold, clean, bore.

Trap

A game of competitive clay pigeon shooting on a formally designed layout. In plan view, one launching machine is located 16 yards in front of a straight line, firing rising targets perpendicular to and away from that line. Five competitors shoot five individual targets at each of five stations along that line. Although each target is presented at slightly randomized vectors, trap emphasizes generally a single type of shot, outgoing and rising, and targets are broken at generally longer ranges than Skeet.

Reflector Sight

A generally non-magnifying optical device that has an optically collimated reticle, allowing the user to look through a partially reflecting glass element and see a parallax free cross hair or other projected aiming point superimposed on the field of view. Invented in 1900 but not generally used on firearms until reliably illuminated versions were invented in the late 1970s (usually referred to by the abbreviation "reflex sight").

Extractors

A part in a firearm that serves to remove brass cases of fired ammunition after the ammunition has been fired. When the gun's action cycles, the extractor lifts or removes the spent brass casing from the firing chamber.

Berm

On an outdoor shooting range, a large pile of dirt that functions as a backstop.

Snap Cap

An inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions. Some folks also use them during dry fire practice to cushion the firing pin as it strikes.

Bolt Face

The forward end of the bolt which supports the base of the cartridge and contains the firing pin.

Charger

A device typically made from stamped metal which holds a group of cartridges for easy and virtually simultaneous loading into the fixed magazine of a firearm.

Quaker Gun

Not really a gun at all. During the U.S. Civil War, both sides would take tree branches or tree trunks, paint them black, and position them so that they appeared to be rifles or artillery pieces. By doing so, they could fool the other side into believing that they had more artillery than they really did.

Crisp Trigger

A trigger that breaks (to release the hammer) easy.