Letter D

The Definition of DST

Arsenal Exchange - Firearms Classifieds - Industry Directory

19 Other Firearms Definitions You Need To Know


Pre-Travel

Some triggers can be pulled slightly backwards before the shooter can feel any tension and before the hammer or striker begins to retract. Pre-travel is any movement of the trigger that begins before the trigger starts to engage.

Practical Shooting

A shooting sport that simulates the use of a small arm in its intended role either as a tool for hunting or personal defense. True practical shooting limits the small arms, ammunition, and accessories used to those items that would actually be used in the role simulated.

Eye Relief

The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.

Red Dot Sight

A type of reflector (reflex) sight for firearms that gives the uses a red light-emitting diode as a reticle to create an aimpoint.

Grain

A unit of weight widely used to express the weight of bullets and of powder charges. Equal to 1/7000 pound.

Buckshot

A type of shotgun ammunition that uses medium-sized to large-sized pellets of .24" in diameter or greater, designed to be discharged in quantity from a shotgun. Generally the larger the pellets, the fewer of them there are in casing.

Point of Impact

The point where the projectile from a firearm hits.

BATF

Short abbreviation for the Bureau of Alcohol, Tobacco, Firearms and Explosives

Muzzleloader

The earliest type of gun, now also popular as modern-made replicas, in which blackpowder and projectile(s) are separately loaded in through the muzzle. The term is often applied to cap-and-ball revolvers where the loading is done not actually through the muzzle but through the open ends of the cylinder's chambers.

Thumb Safety

An external, manual safety which is typically disengaged with the firing-hand thumb.

Reticle

A matrix of dots, posts or lines, visible inside a rifle's telescopic sight, normally adjustable via exterior knobs for windage and elevation. After careful adjustment at a known range, the shooter aims the rifle by superimposing this matrix onto the target. With good estimation or range, cooperation from the wind, a clear eye and a steady hand, he may have a reasonable expectation of hitting his target.

Mercury Recoil Compensator

A device fitted inside the buttstock of a heavily-recoiling gun or rifle, usually containing mercury and a valve. As the gun recoils, the mercury is displaced temporarily, increasing the duration, and thus diminishing the perceived impact of the recoil. The added half-pound of weight doesn't hurt either.

Single Action

An action type that when the trigger is pulled, the only thing the trigger does is drop the hammer (or striker). This applies to both revolvers, semi-automatic and automatic guns. On a single action revolver, the gun must be manually cocked before it can be fired. With semi-automatic and automatic guns that are single action, the only thing the trigger does is drop the hammer, striker or firing pin onto the cartridge. Then the firearm is cocked again when from the recoil of the fired round. A firearm that the gun is cocked and the hammer drops when the trigger is pulled is a double action gun.

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.

Scout Rifle

A concept created by eminent gun writer Col. Jeff Cooper. A scout rifle, generally, is a bolt action carbine firing a medium power round suitable for taking large game (e.g., .308), fitted with a long eye-relief telescopic sight mounted on the barrel, and a back up set of iron sights.

Casing

Also known as a Case. The envelope (container) of a cartridge. For rifles and handguns it is usually of brass or other metal; for shotguns it is usually of paper or plastic with a metal head and is more often called a "shell."

Failure To Fire

Any malfunction that results in no shot fired when the trigger is pulled. Commonly caused by a failure to feed, bad ammunition or a broken firing pin.

Blown Pattern

A shotgun pattern with erratic shot distribution, generally caused by gas escaping past the wads and getting into the shot.

Open Bolt

A type of firearm in which the action is in the open position and the chamber empty prior to firing. When the trigger is pressed the bolt moves forward, chambering a cartridge and firing it and returning to the open position. When firing is stopped the bolt remains open and the chamber empty.