Letter R

The Definition of Rimfire

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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.


19 Other Firearms Definitions You Need To Know


Blown Pattern

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

Peep Sight

An alternate name for Aperture Sight.

Length Of Pull

The distance from the front trigger of a shotgun to the centre of the butt.

Hand

In any mechanism, a small lever that engages a notch to actuate movement in one direction only. Specifically, a small spring-loaded lever attached to the hammer of a revolver which actuates the cylinder to advance one increment and move the next chamber into battery as the hammer is cocked.

Decocker (De-Cocker)

On semi-auto matic pistols, a lever that mechanically lowers the hammer without firing the gun.

Automatic

A type of firearm which, utilizing some of the recoil or some of the expanding-gas energy from the firing cartridge, cycles the action to eject the spent shell, to chamber a fresh one from a magazine, to cock the mainspring and to fire again. Such a firearm will fire continuously as long as the trigger is held back, until the magazine is empty. A machine gun. A firearm thus activated, but which shoots only one bullet with each separate pull of the trigger, while often erroneously referred to as "automatic" is properly termed Semi-Automatic.

Hinge Pin

A short cylindrical rod of hardened steel running laterally near the front of the bar of a break-open gun's action around which the barrel hook revolves when the gun is opened. Over the decades, this pin and its complimentary hook can wear and a gun can sometimes "shoot loose" or "come off the face." The proper cure for this condition is to replace the hinge pin with a new one, slightly oversized, to compensate for wear on both itself and on the barrel hook.

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.

Moon Clip

A moon clip is a ring-shaped or star-shaped piece of metal designed to hold multiple cartridges together as a unit, for simultaneous insertion and extraction from a revolver cylinder. Unlike a speedloader, a moon clip remains in place during firing, and after firing, is used to extract the empty cartridge cases.

Long Rifle

Typically used in the .22 caliber cartridge designation .22 Long Rifle, which is abbreviated .22LR.

Sight Picture

What the shooter sees when looking through the sights at the target.

Deterrent

A material added to an explosive to slow its burning rate.
Something that will prevent or hinder something from happening.

Lockplate

A metal plate on which the firing mechanism is mounted on percussion and earlier firearms.

Frizzen

The part of a flintlock action that receives the blow of the flint-tipped hammer, which then yields tiny molten fragments of steel ,sparks, which fall into the flashpan, igniting the priming charge and thence, through the touchhole, the main charge.

Gauge

System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight equals one pound. The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.) The Gauge/Bore system is also used, by convention, to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel rifles.

Inletting

The process of carving out recesses in wooden stocks with precision, using gouges, chisels and scrapers to accept the steel components of a firearm.

Snub-Nose

Slang word for short barreled revolver.

High-Capacity Magazine

An inexact, non-technical term indicating a magazine holding more rounds than might be considered "average.".

Metallic Cartridge

A cartridge with a metallic case. (Early cartridge cases were made of linen, paper, etc.)