Letter F

The Definition of Firing Line

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Firing Line

A line, either imaginary or marked, from which people shoot their firearms down range.


19 Other Firearms Definitions You Need To Know


Receiver Ring

The portion of the receiver which is threaded so the barrel can be attached to it.

Express Sights

"V" shaped rear leaf sights mounted to a rifle barrel on a block or on a quarter-rib, sometimes solid standing, sometimes folding, and often mounted in a row of similar leaves, each of a slightly different height, marked with the range for which each is regulated

Cock

The term referring to the action of manually drawing the hammer back against its spring until it becomes latched against the sear, or sometimes the trigger itself, arming the hammer to be released by a subsequent pull of the trigger. Some external hammers, and all internal hammers, may be cocked simply by pulling the trigger

Bluing

Also spelled blueing. A passivation process in which steel is partially protected against rust, and is named after the blue-black appearance of the resulting protective finish. True gun bluing is an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe3O4), the black oxide of iron, which occupies the same volume as metallic iron. Bluing is most commonly used by gun manufacturers, gunsmiths and gun owners to improve the cosmetic appearance of, and provide a measure of corrosion resistance to, their firearms.

Pistol Grip

The handle on a pistol. Can also refer to a vertical grip behind the trigger on a rifle.

Sectional Density

The relationship between a bullet's weight and its diameter. A long bullet, such as the original 7.62x54R loading for the Mosin Nagant 91/30, will have a high sectional density and consequently greater penetration than a shorter bullet of similar construction. A shorter bullet with less sectional density will have relatively less penetration, but greater knockdown power.

BATF

Short abbreviation for the Bureau of Alcohol, Tobacco, Firearms and Explosives

Snap Caps

Dummy cartridges with spring-loaded "primers" used to test the mechanical functioning of a firearm, particularly the trigger pulls, hammer-fall and ejector-timing of a break-open gun. It is not advisable to dry-fire a break-open gun on an empty chamber. Hardened steel parts can shatter without the soft brass primer to act as a shock absorber. Snap caps cushion the blow of the hammer and firing-pin when the use of a live cartridge would be impractical.

Picatinny Rail

A metal bar, available in a variety of lengths, with a continuous row of Weaver-like scope mount base slots, which when attached to a firearm, allow convenient attachment of a variety of sights, lights, slings, bipods and other accessories designed to fit this standard system.

Hammer Spur

The thumb-piece on the top rear of the hammer that enables it to be manually drawn back to full cock.

CQC

Abbreviation for Close Quarters Combat.

Dud

A round of ammunition that does not fire.

Zero

A firearm is said to be "zeroed in" when its sights have been adjusted so that the bullet will hit the center of the target when the sights are properly aligned upon the center of the target. The farthest distance from a firearm at which the bullet's path and the point of aim coincide. This term is also used to mean the process of insuring that the sights of a firearm are properly aligned so that where they indicate the bullet will strike is in fact where it strikes.

Takedown

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.

Underlug

The locking lugs on a break-action firearm that extend from the bottom of the barrels under the chamber(s) and connect into the receiver bottom.

Magna

Smith & Wesson term for a revolver grip design introduced in the 1930s where the top of the grip extends higher than it had in earlier configurations, to provide a more comfortable hold.

Boattail

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

Scope

A magnifying tube through which the shooter may see the target and aim the firearm. Scopes contain a reticle, commonly in the shape of a cross, which must be properly centered upon the target for accurate aim.

Short-Stroking

On a pump-action firearm, being too gentle with the fore-end and either not pulling it all the way back at the beginning of the stroke, or not shoving it all the way forward at the end of the stroke. Which may result in the old case or shell failing to eject and a misfeeds, or the gun will not fire when the trigger is pulled. The term is used most often to refer to pump-action shotguns, but it is possible to similarly short-stroke any type of firearm which requires the user to manually cycle the action (lever action rifles, for example).