Letter I

The Definition of Island Rear Sight

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Island Rear Sight

A rear barrel sight base, more articulated than having the sight simply dovetailed into the barrel, but not requiring as much gunsmithing as having it mounted onto a proper quarter-rib.


19 Other Firearms Definitions You Need To Know


Autoloader

A firearm that automatically loads the next cartridge to be fired into the chamber either upon the pull of the trigger in an open bolt design or upon the firing of the previous round in a close bolt design.
Autoloader should not be confused with Automatic or Semi-Automatic since the term Autoloader only applies to how the next round is chambered not how many rounds can be fired per trigger pull. All Automatic and Semi-Automatic firearms are autoloaders. Revolvers, bolt action, lever action and pump action firearms are not autoloaders.

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").

Topstrap

The part of a revolver's frame connecting the recoil shield to the barrel-mounting recess; adding considerable strength compared to that of early black powder Colt revolvers, and providing a base for a rear sight.

Rail Mount

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

Luger

American name for the German "Parabellum" semiautomatic pistol introduced in 1900. The Parabellum was designed by Georg Luger, and based on the earlier Borchardt pistol. The official German military nomenclature was "Pistole '08" or "Po8." At first, it was chambered for the 7.65mm Parabellum round. Soon, it was modified to use the 9mm Parabellum cartridge, which is what most people refer to today when talking about a 9mm cartridge. "Luger" is now a trademark owned by the Stoeger Arms Co.

Rifle Bedding

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

Extractors

A part in a firearm that serves to remove brass cases of fired ammunition after the ammunition has been fired. When the gun's action cycles, the extractor lifts or removes the spent brass casing from the firing chamber.

Powder Charge

The amount of propellant powder that is suitable for specific cartridge-bullet combination, or in the case of shotshells, for a specific weight of shot and wad column.

Wadcutter

A bullet designed with a full diameter flat point. It is primarily used in target competition because it cuts a clean round hole in paper targets that aids in scoring the target.

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.

Dum-Dum

A bullet designed to expand on impact, increasing in diameter to limit penetration and/or produce a larger diameter wound. The two typical designs are the hollow point bullet and the soft point bullet. Expanding bullets were given the name Dum-dum, or dumdum, after an early British example produced in the Dum Dum Arsenal, near Calcutta, India by Captain Neville Bertie-Clay in the the mid-1870s. Modern sef-defensive, JHP (Jacketed Hollow Point), ammunition are based on the original dum-dum ammunition design and principles.

Collateral Damage

Damage that is unintended or incidental to the intended outcome.

Concealed

Hidden from view. A handgun is concealed when it is carried in such a manner that is unseen.

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.

Load

A charge of powder, a projectile or a cartridge. Also, to prepare a gun for firing by inserting ammunition into it.

Toplever

A lever on a break-open gun mounted to the top of the receiver which, when pushed with the thumb (normally) to the right, operates (usually) a Scott Spindle, which in turn withdraws (usually) a Purdey Underbolt from the bites in the lumps of the barrels, allowing them to hinge downwards and the gun to open.

Intercepting Sear

A second sear, poised just behind a second notch in the hammer. It is possible that when a cocked firearm is dropped or sharply jarred, a single sear could jump out of its notch and the hammer could fall, firing the gun accidentally. In this event, an intercepting sear would engage before the hammer could fall completely, preventing an accidental discharge. On a gun with intercepting sears, only by pulling the trigger are both sears moved out of the way simultaneously, allowing the gun to fire. Intercepting sears are usually found on better sidelock actions. They are sometimes found on best boxlocks, and can be recognized by an extra screw behind the action fences, in addition to the usual two screws (or pins) along the lower rear of the receiver.

Backstop

Anything that will safely stop a bullet and prevent it from hitting anything else after the target is struck.