Letter A

The Definition of Armor-Piercing Ammunition

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Armor-Piercing Ammunition

An armor-piercing shell must withstand the shock of punching through armor plating. Shells designed for this purpose have a greatly strengthened case with a specially hardened and shaped nose, and a much smaller bursting charge.


19 Other Firearms Definitions You Need To Know


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.

Isosceles Stance

There are two basic variants of the Isosceles stance, the Traditional Isosceles and Modern Isosceles stance. In both Isosceles stances, the feet parallel pointing toward the target and are roughly shoulder width apart. Both arms are stretched almost equally forward with the gun centered forward, creating the triangular shape which gives the stance its name.

Rifling

Spiral grooves formed into the bore of a gun barrel, which cause the bullet to spin upon firing, thus stabilizing it much like a thrown football. Rifling may be cut, swaged, or forged into the barrel.

Beavertail

A large piece of curved metal at the top of the grip on a pistol which protects the user's hand from getting "bitten" by the hammer or slide. It is nearly always the top part of the grip safety commonly found on many 1911-style pistols.

Parabellum

Latin word meaning "for war." It is actually the proper name of the semiautomatic pistol commonly known in the USA as the "Luger. Because of that pistol and the ammunition created for it, the common 9mm cartridge used nowadays is also known as 9mm Parabellum or 9mm Luger."

Gas Check

A metal cup placed on the end of a lead bullet to protect the lead against the hot gases of the burning powder charge. Used in some types of firearms ammunition when non-jacketed bullets are used in high pressure cartridges, to prevent the buildup of lead in the barrel and aid in accuracy.

Hollow-Point Bullet

A type of expanding bullet with a concavity in its nose to increase expansion on penetration of a solid target. Some hollow-point's are also designed to fragment as they expand. They are least likely to over-penetrate the target and harm an innocent bystander. Commonly used for self-defense.

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Handspanner

German for Hand-Cocking or Cocker/De-Cocker. A type of action on a break-open gun or rifle where, in place of a traditional top tang safety, a somewhat more robust tab is fitted. Normally such a gun is carried in the field loaded, but with the action not cocked, an exceedingly safe condition. Then, when ready to fire, the shooter, instead of pushing a safety tab forward, pushes this larger tab forward, cocking the mainspring, making the gun ready to fire. Then, if the shot is not taken, he may simply slide this tab rearwards again, de-cocking the gun and returning it to the still-loaded, but very safe position.

Jeweling

A cosmetic process to enhance the looks of firearm parts, such as the bolt. The look is created with an abrasive brush and compound that roughs the surface of the metal in a circular pattern.

Obturation

The process of a bullet expanding under pressure to fit the bore of the firearm, or a cartridge case expanding under pressure to seal the chamber.

Gloaming Sight

A second, folding or pop-up front sight bead of larger than usual size, perhaps not as accurate as a normal fine bead, but easier to see in the gloaming (twilight) or dawn.

Collimator Sight

Also known as collimating sight or occluded eye gunsight, a Collimator Sight is a type of optical "blind" sight that allows the user looking into it to see an illuminated aiming point aligned with the device the sight is attached to regardless of eye position (parallax free). The user can not see through the sight so it is used with both eyes open while one looks into the sight, with one eye open and moving the head to alternately see the sight and then at the target, or using one eye to partially see the sight and target at the same time.

Cant

To tilt a gun to one side or the other, complicating sighting considerably. Can cause material loss of accuracy, particularly with a rifle at longer ranges. Some better long range target rifles are equipped with Spirit Level sights to help control canting.

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Pull

The entire process of making the trigger complete its journey past the trigger break.

Cover Garment

Any piece of clothing that covers the holstered gun. When the gun is worn on the belt, the most common types of cover garments are vests, sweaters, and jackets.

Light Double Action

A double-action semi-automatic firearm which is designed to have a much lighter trigger pull than is usual for a double action.

Frangible

A bullet that is designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the danger behind the intended target. Examples are the Glaser Safety Slug and the breaching round.