Letter S

The Definition of Scope

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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.


19 Other Firearms Definitions You Need To Know


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.

High Brass

By convention, powerfully loaded shotgun cartridges for hunting are generally manufactured with relatively longer brass end-caps than lower powered cartridges intended for target shooting. While different-sized brass bases are of virtually no consequence to the strength of the shell in relation to the steel breech of the gun itself, they do help the shooter identify the relative power of cartridges at a glance.

Carbine

A rifle with a relatively short barrel.

POA

Abbreviation for Point of Aim

Metallic Cartridge

A cartridge with a metallic case. (Early cartridge cases were made of linen, paper, etc.)

Pellet (shotgun)

Small spherical projectiles loaded in shotshells and more often called "shot."

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.

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 As the handle is operated, the bolt is unlocked, the breech is opened, the spent shell casing is withdrawn and ejected, the firing pin is cocked, and finally a new round/shell (if available) is placed into the breech and the bolt closed.

Inertia Firing Pin

A firing pin which moves freely forward and backward in the breechblock.

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

Kurtz

German for "short." Seen as part of a cartridge designation. On some German manufactured guns that use .380 ACP, the designated caliber is 9mm Kurtz (9mm Short), which is also the same as the Italian 9mm Corto

Centerfire (Center Fire)

A cartridge with its primer located in the center of the base of the case.

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

Gape

The degree to which the barrel(s) of a break-open gun drop down; the size of the opening space, which should be sufficient to allow for ease of loading, unloading and properly-functioning ejection. A good gape is easier to achieve on a side-by-side than an over & under where the bottom barrel is well-enclosed by the action body.

Cover Hold

Sometimes also known as cover-up hold. A sight picture of when the center of the target is completely covered by the front sight when the sights are properly aligned. Also see center hold and six o'clock hold.

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.

Controlled Pair

Two shots fired in rapid succession. It is different from a double tap because in a controlled pair, the second shot will be fired after the shooter has obtained a second sight picture, whereas in a double tap both shots are fired based upon the initial sight picture alone.

Powder Charge

The amount of propellant powder that is suitable for specific cartridge-bullet combination, or in the case of shotshells, for a specific weight of shot and wad column.