Letter R Firearms Glossary

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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.

Rail

A feature on some guns which allows various aftermarket accessories to be attached the firearm such as flashlights or lasers. On pistols, if equipped, the rail is on the underside of the frame below the barrel. On rifles, a rain can be found above or below the barrel, with AR type rifles, the forestock can be made of rails allowing all kinds of attachments in various positions.

Rail Mount

Any type of accessory that can be attached to a firearm's rail.

Railgun

A railgun is an electrically powered electromagnetic projectile launcher based on similar principles to the homopolar motor.
Using a magnetic field powered by electricity, a rail gun can accelerate a projectile up to 52,493 feet (16,000 meters) per second.
A railgun consists of two parallel metal rails (hence the name) connected to an electrical power supply. When a conductive projectile is inserted between the rails (at the end connected to the power supply), it completes the circuit. Electrons flow from the negative terminal of the power supply up the negative rail, across the projectile, and down the positive rail, back to the power supply.

Ramrod

A long, slender, dowel-like tool used to force powder and shot down the bore of a muzzle-loading firearm. For hand-fired guns, normally retained in some kind of receptacle attached to the gun's barrel. Carried separately for muzzle-loading cannon.

Range Finder

A device used to determine the range to a target. Many range finders work by bouncing a laser beam off the target or nearby object and measuring the time for the reflection to arrive back at the instrument. It is also possible to use various passive optical devices such as a mil-dot telescopic sight.

Rate of Fire

The frequency at which a firearm can fire its projectiles.

Reactive Targets

Targets that do something when you hit them, such as fall over, burst, send up smoke, or make a noise.

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.

Receiver

The housing for a firearm's breech (portion of the barrel with chamber into which a cartridge or projectile is loaded) and firing mechanism. In semi-automatic handguns and revolvers, this part is typically called the frame.

Receiver Ring

The portion of the receiver which is threaded so the barrel can be attached to it.

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.

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#39;t hurt either.

Recoil Crossbolt

A steel bolt, mounted transversely through a rifle stock just under and behind the front (and sometimes rear) receiver ring, sometimes concealed in the wood and usually against which the action is carefully bedded. When properly fitted, it helps distribute the recoil and reinforces stock at the point where wood has been removed to accept the action. Recoil crossbolts can be recognized by the flush-mounted circular steel fittings on the side of the stock, but are sometimes finished with contrasting wooden plugs and sometimes concealed completely. Also called Reinforcing Crossbolt.

Recoil Lug

A stout flange, invariably incorporated into the underside of the front receiver ring of a bolt action, and also frequently incorporated into the underside of the barrel of a heavily-recoiling rifle, which when properly bedded, transfers recoil to the stock.

Recoil Operation

Recoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action.

Recoil Pad

A soft appendage, usually of some kind of rubber, often fitted to the butt end of a shoulder-mounted firearm to reduce the sensation of recoil. A recoil pad has the additional benefit of being less vulnerable to damage than a checkered wood butt or a brittle horn or plastic buttplate.

Recoil Spring

The recoil spring is the powerful spring that cushions the slide in its rearward travel and then sends the slide forward again with enough force to drive the fresh round firmly into the chamber. The strength of the recoil spring is calibrated to run the slide without any outside assistance.

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.

Reflector Sight

A generally non-magnifying optical device that has an optically collimated reticle, allowing the user to look through a partially reflecting glass element and see a parallax free cross hair or other projected aiming point superimposed on the field of view. Invented in 1900 but not generally used on firearms until reliably illuminated versions were invented in the late 1970s (usually referred to by the abbreviation "reflex sight").

Repeater

A type of firearm capable of discharging multiple individual shots in sequence, fed from a magazine, via the operation a lever, bolt, slide or some other form of manual operation.

Reset Point

The point of the trigger's return at which the gun's internal mechanisms are ready to fire another round.

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.

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.

Revolver

A repeating firearm in which the ammunition is held in a multi-chambered cylinder, which is rotated to bring each chamber in line with the barrel. Most revolvers are handguns, although shoulder-fired arms have been made using this sort of mechanism.

Ricochet

A rebound, bounce or skip off a surface, particularly in the case of a projectile.

Riding the Slide

Racking the slide incorrectly by allowing your hand to rest upon the slide as it moves forward during the loading procedure. Riding the slide is a common cause of misfeeds and other malfunctions.

Rifle

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

Rifle Bedding

A process of filling gaps between the action and the stock of a rifle with an epoxy based material.

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.

Right To Bear Arms

The unalienable right of all of the people, stated in the Second Article of The Bill of Rights, to possess and use personally owned firearms for sport, recreation, personal protection, and the defense of the nation.

Rim

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

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.

Rimless

A cartridge in which the base diameter is the same as the body diameter. The casing will normally have an extraction groove machined around it near the base, creating a "rim" at the base that is the same diameter as the body diameter.

Riot Gun

A popular term for a short barreled repeating shotgun as frequently used in law enforcement and personal protection.

Riot Gun

A popular term for a short barreled repeating shotgun as frequently used in law enforcement and personal protection.

Rolling Block

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.

Round Gun

Slang term for a revolver.