Letter T

The Definition of Throat Erosion

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Throat Erosion

The wearing of the portion of the barrel where the gas pressure and heat is highest as the projectile leaves the chamber. The greater the chamber pressure the more rapid throat erosion occurs which is compounded by rapid firing which heats and weakens the steel.


19 Other Firearms Definitions You Need To Know


Ballistic Fingerprint

A fired case has marks upon it that it picked up from the extractor, ejector, and breechface of the gun when the shot went off. A bullet fired through a rifled barrel also has rifling marks unique to the barrel that launched it. A record of these marks, when stored in a central database, is called a ballistic fingerprint. Some states require this record to be made by law, so that individual guns can be located from bullets or casings found at the scene of a crime.

Quarter Master

The person who supervises stores and distributes supplies and provisions.

Parallax

This occurs in telescopic sights when the primary image of the objective lens does not coincide with the reticle.Telescopic sights often have parallax adjustments to minimize this effect.

Smokeless Powder

The propellant powder used in modern ammunition. It is not an explosive, but rather a flammable solid that burns extremely rapidly releasing a large volume of gas. Commonly called "gunpowder" and usually made from nitrocellulose, or nitrocellulose and nitroglycerin. It is classified as a "Flammable Solid" by the Department of Transportation.

Flat Nose

A bullet shape with a flat nose rather than a rounded one.

Rear Sight

The rear sight is placed at the end of the barrel nearest the shooter. It may be in the shape of a square notch, a U, a V, a ring, or simply two dots designed to be visually placed on either side of the front sight while shooting.

Caliber

The diameter of the bore of a firearm measured as a fraction of an inch. Although such a measurement may be frequently stated in millimeters. It is correctly expressed as ".40 caliber" (note the decimal point) or as "10 millimeter" (without "caliber" or the leading decimal point). Caliber numbers when used to identify the size of the bullet a gun will file are usually followed by words or letters to create the complete name of the cartridge. These letters often represent a brand name or an abbreviation for the name of the company that first introduced the round.

Clearing

Unloading a gun and double checking that it is unloaded or fixing a malfunction so that the gun is ready to fire again.

Brass

The term used for the casing on modern rifle and pistol ammunition. It is usually made out of brass but can also be aluminum or steel. The casing on a shotgun shell is usually refered to as a hull

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.

Combination Gun

A shoulder-held firearm that has two barrels; one rifle barrel and one shotgun barrel. Most combination guns are of an over/under design (abbreviated as O/U), in which the two barrels are stacked vertically on top of each other, but some combination guns are of a side-by-side design (abbreviated as SxS), in which the two barrels sit beside each other.

Brady Law

Brady Handgun Violence Prevention Act of 1993. The Brady Handgun Violence Prevention Act of 1993 mandates background checks of gun buyers in order to prevent sales to people prohibited under the Gun Control Act of 1968 legislation. Requires checks to be performed through the FBI's National Instant Criminal Background Check System (NICS). Records of who has been checked are not preserved because federal law prohibits the creation of a national registry of gun ownership. Sales by unlicensed private sellers who are not engaged in gun dealing as a business are not subject to the checks under federal law, though they are required by some states.

Glock Auto Pistol

A type of .45 caliber ammunition designed in 2002 by Ernest Durham for use in the Glock Model 37.

Velocity

The speed at which a projectile travels. Velocity is usually measured in feet per second or metres per second.

OFF

Oregon Firearms Federation. OFF is a Pro-Gun rights group based in Oregon and was founded in 1998.

Thumbhole Stock

A rifle stock, with a sculptured throughole at the wrist for the thumb, said to be more ergonometric to hold than a traditional stock. Apart from being slower to mount, totally useless for a counter-dexterous person, it is so unmitigatedly graceless as to be beneath consideration.

Crosshairs

The cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.

Safety Lug

An extra flange behind the bolt handle, at the rear of a bolt action receiver (notably the Mauser Model 1898), which uses the bolt handle as an extra locking surface in the extremely unlikely event of forward bolt lug failure.

Checkering

A regular pattern of fine grooves cut into the surface of a stock to aid in gripping a gun. Originally done for utility only, checkering has become an art form in itself; craftsmen adorning the borders with ribbons, fleur-de-lys, floral carving, etc. The amount of coverage, the precise regularity, and the number of lines per inch indicate the quality of the work. Too-fine checkering, however, defeats the purpose of the work altogether.