Letter O

The Definition of Over-Under

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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.


19 Other Firearms Definitions You Need To Know


Open Tip Match

A rifle projectile made with the tip of the bullet open as a means of increasing accuracy as compared to standard military bullets that are made with a closed tip and an open base. The are not designed to expand like a hollow point bullet but may fragment.

Rifle

A shoulder-fired long gun which has a rifled barrel.

Button Rifling

Rifling that is formed by pulling a die made with reverse image of the rifling (the 'button') down the pre-drilled bore of a firearm barrel.

Base Wad

The paper filler at the rear of the powder charge of the shotgun shell.

WRF

Abbreviation for Winchester Rim Fire.

Propellant

The substance which imparts movement to the projectile in a firearm. In a firearm, usually powder. In an airgun the propellant is air or Co2

Sawed-Off Shotgun

Common term for federally restricted "short-barreled shotgun (rifle)" as with a conventional shotgun with barrel less than 18" (rifle less than 16") or overall length less than 26.

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.

Magazine Loader

A mechanical device to make it easier to fill magazines using less hand strength and without hurting one's fingertips or thumbs.

Eyes

Slang for eye protection. Referes to either goggles or safety glasses

Comb

The top of a gun's stock, where a shooter rests his cheek when mounting a gun. As it is the top of the stock that determines the position of one's eye, and one's eye is the rear sight on a shotgun, the position of the comb is very important in determining the proper fit of a shotgun.

Tracer

A type of ammunition that utilizes a projectile or projectiles that contain a compound in its base that burns during its flight to provide a visual reference of the projectile's trajectory.

Berm

On an outdoor shooting range, a large pile of dirt that functions as a backstop.

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.

Cold Range

A condition on a shooting range that is completely safe. Any firearms at the range are on the benches, unloaded with open actions and all people have stepped away from the firing line.

Blowback

A semi-automatic firearm whose breechblock and barrel are not mechanically locked together when fired. In such case the breechblock immediately begins to separate from the barrel upon firing. Blowback is used in comparatively low powered weapons, in which inertia of the breechblock, and cartridge wall adhesion against the chamber, are sufficient enough to retard opening until breech gas pressures have fallen to a safe level.

Misfeed

Is a failure of the next round to completely enter the chamber. Misfeeds and failures to feed are very similar, a failure to feed is a round that never even leaves the top of the magazine, while a misfeed is a round that leaves the magazine but does not enter the chamber.

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.

Rimfire

Helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy.