Letter D

The Definition of Die

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Die

A piece of tooling used to form a sequence of uniform parts through the use of heat and/or pressure; especially, in firearms terminology used to form brass cartridge cases accurately to their correct size for reloading.


19 Other Firearms Definitions You Need To Know


Recoil

The tendency of a firearm when fired to move backwards, and a little upwards as a reaction to the force of the projectile moving down the barrel. As Newton says, to every action there is always an equal and opposite reaction. The mass of the firearm provides some inertia to counteract the momentum of recoil. What remains is absorbed by at the shoulder or the hand. The heavier the gun, the less the recoil. The more powerful the cartridge, the more the recoil.

Jump

The amount of change in the bore axis, measured both vertically and horizontally, while the projectile moves from the chamber to the muzzle when it is fired.

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.

Dust Cover

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

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.

Shoulder

To bring the butt of a long gun's stock to the shooter's shoulder, preparatory to firing the gun.

Iron Sights

The mechanical sighting system which usually comes with the firearm made of metal with no optics.

Ear Muffs

Hearing protection that completely covers both ears and is usually attached to a headband.

Sight Alignment

The manner in which the sights are lined up properly in front of the shooter's eye, to form a straight path to the target.

Bullet

The single projectile expelled from a gun. It is not the same as a cartridge, the cartridge is complete package, which includes the case, primer, powder, and bullet, which is called or a round. Bullets can be of many materials, shapes, weights and constructions such as solid lead, lead with a jacket of harder metal, round-nosed, flat-nosed, hollow-pointed, etc.

Modern Isosceles

In the Modern Isosceles stance, the feet are roughly shoulder width apart, with the gun-side foot closer to the target than the off-side foot. The knees are flexed, and the entire body leans slightly toward the target. The shoulders are closer to the target than the hips, and the hips are more forward than the knees. The shoulders are rotated forward and the head, rather than being upright, is vultured down behind the sights. The entire body thus has an aggressively forward appearance, and is poised to move quickly if necessary.

Double-Base Powder

A rapidly burning powder made by absorbing nitroglycerine into nitrocellulose (guncotton).

Ejection Port

The opening through which the empty, spent ammunition case is ejected from of a firearm.

Annulus

A tiny circular recess at the base of a cartridge case surrounding the primer pocket. Recoil from fired cartridges invariably impress a discernable ring on the breech or bolt face of a firearm, providing some evidence of the amount of use it has seen.

Back Action

A sidelock action where the mainspring is mounted rearward towards the butt. The back action is often used in double rifles where the need for strength requires as little steel as possible be removed from the bar of the action.

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.

Over-Under

Can also be spelled Over/Under, OverUnder or Over and Under. A firearm (most commonly a shotgun) with two barrels that are vertically aligned with each other, one on top of the other.

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.

Matchlock

An early system of ignition for muzzle-loading firearms where a priming charge is loaded into a flashpan with a separate, manually-operated cover. To fire, the cover is opened and then a slowly smoldering wick, held in the nose of the curved arm, is lowered by means of a lever (precursor to a trigger) to ignite a priming charge which then ignites the main propellant charge inside the barrel.