Letter R

The Definition of Rim

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Rim

The edge on the base of a cartridge case which stops the progress of the case into the chamber.


19 Other Firearms Definitions You Need To Know


Casehardening

A heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle. The parts to be casehardened are packed in a crucible with carbon-rich media such as bone meal and charcoal, heated to bright orange, about 1800F, then quenched in bubbling oil. Also called Carbonizing.

Lock

The firing mechanism of a a muzzle-loading weapon. In breech-loading firearms, the lock is the firing mechanism and breech-sealing assembly.

Choke

A constriction at or near the muzzle of a shotgun barrel that affects shot dispersion.

Suppressor

Incorrectoly sometimes referred to as a silencer, it is used to reduce the sound of a firearm's discharge. They do not actually silence most firearms but rather lower the intensity of the muzzle blast and change the sound characteristics (works similarly to an automotive muffler by disrupting and spreading out the sound waves). The possession, use, and transportation of silencers have been tightly controlled under federal law since 1934. Any device which reduces the sound of discharge by more than 2 dB is considered by the BATF to be a suppressor.

Picatinny Rail

A metal bar, available in a variety of lengths, with a continuous row of Weaver-like scope mount base slots, which when attached to a firearm, allow convenient attachment of a variety of sights, lights, slings, bipods and other accessories designed to fit this standard system.

Doughnut Pattern

A shotgun pattern with a hole in the middle generally caused by the interference of the top wad.

Black Powder

Also known as Gun Powder. A mixture of sulfur, charcoal, and potassium nitrate. It burns rapidly, producing a volume of hot gas made up of carbon dioxide, water, and nitrogen, and a solid residue of potassium sulfide. Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. Modern firearms do not use the traditional black powder described here, but instead use smokeless powder.

Ear Plugs

Hearing protection that fits inside the ear canal.

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.

Printing

Is when the outline of the concealed handgun may be discerned through the outer clothing.

Primer

A small metal cup that contains a tiny explosive charge that is sensitive to impact. A primer is placed in the base of a shell casing to ignite the powder of the completed cartridge. It is detonated by the striking of a firing pin in the firearm.

Cable Lock

A cable with a padlock at the end. It is threaded through the action of the firearm rendering the gun safe and useless until the lock is removed.

Bolt Thrust

The amount of rearward force exerted by the propellant gases on the bolt or breech of a firearm action or breech when a projectile is fired. The applied force has both magnitude and direction, making it a vector quantity.

Winchester Short Magnum

More commonly known as WSM, it is a family of centerfire cartridges designed by Winchester Repeating Arms Company

Matchlock

A black powder muzzleloading firearm action which relies upon a serpentine or S-shaped piece of metal to hold a smoldering match. By pressing the lower end of the serpentine, the upper end holding the burning match contacts the priming powder in the pan.

Burst Mode

A firing mode enabling the shooter to fire a predetermined number of rounds with a single pull of the trigger.

Passive Safety

Any safety, internal or external, which functions apart from the shooter's conscious control. Grip safeties are one example of a passive external safety.

Shot Size

The size of the pellets in a shotgun shell.

Field Gun

A shotgun, generally stocked to shoot where it is pointed and of relatively light weight because one often carries it a great distance for upland birds, the consequent recoil not being an important factor because one actually shoots it very little.