Letter Z Firearms Glossary

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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.

Zeroing

The act of setting up a telescopic or other sighting system so that the point of impact of a bullet matches the sights at a specified distance.


18 Other Firearms Definitions You Need To Know


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.

COF

Abbreviation for Course of Fire.

Single Shot

A firearm that is only capable of holding one shot at a time. Each round must be loaded into the chamber manually by hand before each shot.

Eye Relief

The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.

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.

Weaver Stance

In the Weaver stance, the body is bladed partly sideways in relation to the target rather than squared towards it (think boxing or martial arts fighter stance). The elbows are flexed and pointed downward. The strong-side arm is slightly straighter than the weak-side arm. Even though the legs are not square to tharget, the hips should be square to the target. The feet should be pointed at the target. The shooter pushes out with the gun hand, while the weak hand pulls back. This produces a push-pull tension which is the chief defining characteristic of the Weaver stance.

Adjustable Stock

The stock is the wooden, polymer, or metal handle of a long gun that extends from the trigger back to where the gun is braced against the shoulder. An adjustable stock is one that can be easily lengthened or shortened to fit shooters of different sizes.

Bolt Action

A type of firearm action in which the guns's bolt is operated manually by the opening and closing of the breech (barrel) with a small handle. As the handle is operated, the bolt is unlocked, the breech is opened, the spent shell casing is withdrawn and ejected, the firing pin is cocked, and finally a new round/shell (if available) is placed into the breech and the bolt closed.

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.

Cylindro Conoidal Bullet

A hollow base bullet, shaped so that, when fired, the bullet will expand and seal the bore. It was invented by Captain John Norton of the British 34th Regiment in 1832, after he examined the blow pipe arrows used by the natives in India and found that their base was formed of elastic locus pith, which by its expansion against the inner surface of the blow pipe prevented the escape of air past it.

BB

A type of steel round shot fired from air rifles. The name originated from the size of steel balls used in a shotgun of the same size (.177 caliber). In a 12 guage shotgun shell using BB size shot, there will be typically 90 BBs in a shell

Folding Stock

A long gun stock that may be doubled over for conveniently compact storage.

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.

Gun

A firearm.

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).

Dud

A round of ammunition that does not fire.

MOA

Abbreviation for Minute Of Angle

Pattern

A shotgun term which refers to the manner in which the pellets spread out as they exit the gun. "The pattern" refers to the overall shape of the entire set. A tight pattern is one in which the pellets are closely grouped when they land on target. A loose pattern is one in which the pellets are widely spread.