Letter C

The Definition of Collimator Sight

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Collimator Sight

Also known as collimating sight or occluded eye gunsight, a Collimator Sight is a type of optical "blind" sight that allows the user looking into it to see an illuminated aiming point aligned with the device the sight is attached to regardless of eye position (parallax free). The user can not see through the sight so it is used with both eyes open while one looks into the sight, with one eye open and moving the head to alternately see the sight and then at the target, or using one eye to partially see the sight and target at the same time.


19 Other Firearms Definitions You Need To Know


Quaker Gun

Not really a gun at all. During the U.S. Civil War, both sides would take tree branches or tree trunks, paint them black, and position them so that they appeared to be rifles or artillery pieces. By doing so, they could fool the other side into believing that they had more artillery than they really did.

Gas Check

A metal cup placed on the end of a lead bullet to protect the lead against the hot gases of the burning powder charge. Used in some types of firearms ammunition when non-jacketed bullets are used in high pressure cartridges, to prevent the buildup of lead in the barrel and aid in accuracy.

Forend Iron

The steel skeleton of the forend (above), into which any moving parts are fitted and which mates to and revolves about the action knuckle when the gun is opened.

Cast Off

An offset of a gun stock to the right, so that the line of sight aligns comfortably with the right eye while the butt of the stock rests comfortably on the right shoulder. Almost all right-handed shooters benefit from a little castoff and most custom built guns are made this way. The only question is how much. The castoff of a gun is about right when, with the gun comfortably mounted, the front bead lines up with the center of the standing breech.
A stock offset to the left, for shooting from the left shoulder is said to be

Choke Tubes

Short, interchangeable cylinders, of subtly different internal tapers, that screw into a threaded recess at the muzzle of a shotgun. By inserting different choke tubes, one can alter the shot pattern thrown by the gun.

Second Amendment

The second article in the United States Bill of Rights which states, "A well regulated militia being necessary for a free state, the right of the people to keep and bear arms shall not be infringed."

Group

A set of holes in a target left by a succession of bullets fired from the same rifle or handgun, using the same ammunition and sight setting. Fired (within the limits of one's marksmanship ability) to determine the inherent accuracy of the rifle/ammunition combination, and to aid in the proper adjustment of the sights.

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.

Bullpup

A firearm configuration where the magazine and action are behind the trigger.

Drop Safety

A mechanical safety that prevents a gun from firing when it is unintentionally dropped.

Shooting Sticks

A pair of slender and easily-carried wooden dowels or sticks, which when held, crossed, in the fingers of the left hand while also supporting the forend of a rifle, usually shooting offhand, provides somewhat enhanced stability for a more accurate shot.

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.

Turn-Bolt Action

A bolt action which is locked by pressing the bolt handle in and down, thereby turning its locking lugs into the receiver.

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.

Magna

Smith & Wesson term for a revolver grip design introduced in the 1930s where the top of the grip extends higher than it had in earlier configurations, to provide a more comfortable hold.

POA

Abbreviation for Point of Aim

Ricochet

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

Neck

The forward portion of a bottlenecked cartridge case. Also the portion of a rifle chamber in which the neck of the cartridge case rests.

Cocked

A state of readiness of a firearm. The hammer (or similar mechanism if there is no hammer) only needs to be released by the trigger to cause the gun to fire.