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


Casehardening

A heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle. The parts to be casehardened are packed in a crucible with carbon-rich media such as bone meal and charcoal, heated to bright orange, about 1800F, then quenched in bubbling oil. Also called Carbonizing.

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.

Twist

The length, within a rifled barrel, required to accomplish one full rotation. 1:12 Twist, means a bullet passing down the bore would complete one revolution in twelve inches. 1:7 Twist, means a bullet passing down the bore would complete one revolution in seven inches, which makes it a tighter twist than 1:12. Different weights of bullet require appropriate rates of twist.

Yaw

The heading of a bullet, used in external ballistics that refers to how the Magnus effect causes bullets to move out of a straight line based on their spin.

Dust Cover

A small hinged or sliding door covering the ejection port of a firearm to prevent detritus from clogging the works.

Airgun (Air Gun)

A variety of pneumatic gun that propels projectiles by means of compressed air or other gas, in contrast to firearms, which use a propellant charge. Both the rifle and pistol forms (air rifle and air pistol) typically propel metallic projectiles, either pellets, or BBs. Certain types of air guns, usually rifles, may also propel arrows.

Hand-Detachable Locks

The firing mechanism of a break-open gun which may be removed for inspection or cleaning without the use of tools. The release latch may be plainly visible or concealed. A feature typically seen on sidelock guns but also on the Westley Richards "droplock" boxlock action.

Standing Breech

The face of the action of a break-open firearm which houses the firing pins and receives the direct recoil of the fired round.

CQB

Abbreviation for Close Quarters Battle.

Racking the Slide

Pulling the slide back to its rearmost position, and then letting it go forward under its own spring tension. Racking the slide loads the chamber and prepares the gun to fire in a semi-automatic handgun.

Primer

A small metal cup that contains a tiny explosive charge that is sensitive to impact. A primer is placed in the base of a shell casing to ignite the powder of the completed cartridge. It is detonated by the striking of a firing pin in the firearm.

Short Trigger

A trigger that doesn't have to travel very far before it reaches the break. In a 1911 semi-auto pistol, a short trigger is a different part than a long trigger, and (in addition to providing less motion) it features a shorter reach which may be of benefit to a small-handed shooter.

WCF

Abbreviation for Winchester Centerfire.

Chapman Stance

The Chapman stance uses the same push-pull tension which defines the Weaver, but instead of both elbows being bent, the gun side elbow is held straight and locked in place. Assuming a right-handed shooter, the right arm is punched straight out, while the left elbow is bent and the left hand pulls back to provide tension. As a result of this change, Chapman gets its stability from both muscle and skeletal support. This makes it a little more friendly than Weaver for those who lack upper-body muscle strength.

Choke

A constriction at or near the muzzle of a shotgun barrel that affects shot dispersion.

Trigger Control

Not putting your finger on the trigger until your sights are on target, then pulling the trigger smoothly, and following through by realigning the sights before allowing your finger to come off the trigger.

Hair Trigger

A trigger that breaks from an extremely light touch.

Limp Wristing

A floppy, limp wrist while shooting.

Neck

The forward portion of a bottlenecked cartridge case. Also the portion of a rifle chamber in which the neck of the cartridge case rests.