Letter E

The Definition of Ejection Port

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Ejection Port

The opening through which the empty, spent ammunition case is ejected from of a firearm.

19 Other Firearms Definitions You Need To Know


A type of shotgun ammunition that uses medium-sized to large-sized pellets of .24" in diameter or greater, designed to be discharged in quantity from a shotgun. Generally the larger the pellets, the fewer of them there are in casing.

Sight Picture

What the shooter sees when looking through the sights at the target.


The part of a flintlock action that receives the blow of the flint-tipped hammer, which then yields tiny molten fragments of steel ,sparks, which fall into the flashpan, igniting the priming charge and thence, through the touchhole, the main charge.

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.


A firearm that can be separated into (at least) two subassemblies in order to make a shorter package than when put together, without tools. There is no specific requirement regarding how this disassembly must be accomplished; the mechanical design is up to the creativity of the maker. This arrangement allows for more convenient transportation of a firearm, but with rifles, where the action normally separates from the barrel, usually at a small sacrifice in accuracy. Takedown firearms can also be called take-apart firearms. Good examples of a takedown guns are the Henry AR-7 Survival Rifle, the Ruger 10/22 Takedown or the TNW Aero.


Sloppy movement (slack) of a trigger before the actual point of let-off.

Iron Sights

The mechanical sighting system which usually comes with the firearm made of metal with no optics.


A secure storage place for ammunition or explosives. On a firearm, it is the container, either fixed to a firearms's frame or detachable, which holds cartridges waiting to be fed into the gun's chamber.
Detachable magazines for the same gun may be offered by the gun's manufacturer or other manufacturers with various capacities. A gun with a five-shot detachable magazine, for instance, may be fitted with a magazine holding 10, 20, or 50 or more rounds.
Box magazines are most commonly located under the receiver with the cartridges stacked vertically.
Tube or tubular magazines run through the stock or under the barrel with the cartridges lying horizontally (like on a shotgun or lever action rifle.
Drum magazines hold their cartridges in a circular mode (for example the famous drum magazine on a Thompson submachine gun).
On a revolver, the magazine is known as the cylinder.
Internal magazines are built into the firearm and are not removable. Examples of internal magazines are the tube magazines of a shotgun or the magazine on a Mosin Nagant.
A magazine is not a clip!

Curio and Relic

Firearms which are of special interest to collectors by reason of some quality other than is associated with firearms intended for sporting use or as offensive or defensive weapons. To be recognized as curios or relics, firearms must fall within one of the following categories:

  1. Firearms which were manufactured at least 50 years prior to the current date, but not including replicas thereof;
  2. Firearms which are certified by the curator of a municipal, State, or Federal museum which exhibits firearms to be curios or relics of museum interest; and
  3. Any other firearms which derive a substantial part of their monetary value from the fact that they are novel, rare, bizarre, or because of their association with some historical figure, period, or event. Proof of qualification of a particular firearm under this category may be established by evidence of present value and evidence that like firearms are not available except as collector's items, or that the value of like firearms available in ordinary channels is substantially less.
A special Curios or Relics license is available from the BATF, which allows collectors to buy eligible firearms in interstate commerce.


The process of carving out recesses in wooden stocks with precision, using gouges, chisels and scrapers to accept the steel components of a firearm.

Firing Pin

A needle like metal part of a modern firearm that gives a vigorous strike to the primer initiating the firing of the cartridge.

Pellet Gun

An air gun that shoots a skirted pellet.

Low Kneeling

A shooting position in which one or both knees are touching the ground and the shooter is as low as possible.

Chamber Throat

This is the area in the barrel that is directly forward of the chamber, which tapers to the bore diameter.


Is a failure of the next round to completely enter the chamber. Misfeeds and failures to feed are very similar, a failure to feed is a round that never even leaves the top of the magazine, while a misfeed is a round that leaves the magazine but does not enter the chamber.


Abbreviation for Open Tip Match.


The setting on the sights used to accommodate the wind or adjust for horizontal (side-to-side) errors in the alignment of the sights with the bore of the firearm.


A smooth, sometimes contoured plate, within a magazine, at the top of a spring, across which cartridges slide when being loaded into a chamber.

Polygonal Rifling

A type of gun barrel rifling where the traditional lands and grooves are replaced by "hills and valleys" in a rounded polygonal pattern, usually a hexagon or octagon. Polygons with a larger number of edges provide a better gas seal in relatively large diameter polygonally rifled bores.