Letter K

The Definition of Keyhole

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Keyhole

The tendency of a bullet to tip in flight and hit a target sideways, leaving a distinctly oblong hole. This destabilization of the spinning bullet in flight is typically caused by a bullet weight inappropriate for the rate of twist of the rifled barrel, an out-of-balance bullet or its having nicked an impediment such as a blade of grass, in flight.


19 Other Firearms Definitions You Need To Know


Key Fastener

A horizontal wedge, press-fit through the forend of a vintage gun, through a lump attached to the underside of the barrel and out the other side of the forend. To secure the forend in position. Also called a crosspin or a wedge fastener.

SBS

Abreviation for short-barreled shotgun.

Lever Action

A type of firearm action which uses a lever located around the trigger guard area, (often including the trigger guard itself) to load fresh cartridges into the chamber of the barrel when the lever is worked.

Multi-Barreled

A gun with more than one barrel, the most common being the double-barreled shotgun.

Break Action

A firearm whose barrels are hinged, and rotate perpendicular to the bore axis to expose the breech and allow loading and unloading of ammunition.

Failure To Fire

Any malfunction that results in no shot fired when the trigger is pulled. Commonly caused by a failure to feed, bad ammunition or a broken firing pin.

Safety

A device, incorporated into the design of most firearms actions that, when engaged, should prevent the discharge of the firearm. Some safeties are more positive than others. A safety device is not a perfect substitute for the general principles of responsible gun handling. Never point a gun in a direction you do not intend to shoot

Bandolier

A pocketed belt for holding ammunition and cartridges. It was usually slung over the chest. Bandoliers are now rare because most military arms use magazines which are not well-suited to being stored in such a manner. They are, however, still commonly used with shotguns, as individual 12 gauge shells can easily be stored in traditionally designed bandoliers.

Brass

The term used for the casing on modern rifle and pistol ammunition. It is usually made out of brass but can also be aluminum or steel. The casing on a shotgun shell is usually refered to as a hull

Percussion Cap

A small metal explosive-filled cup which is placed over the nipple of a percussion firearm. As the cap is struck by the hammer, it explodes and sends a flame through the flashhole in the nipple to the main powder charge.

High Brass

By convention, powerfully loaded shotgun cartridges for hunting are generally manufactured with relatively longer brass end-caps than lower powered cartridges intended for target shooting. While different-sized brass bases are of virtually no consequence to the strength of the shell in relation to the steel breech of the gun itself, they do help the shooter identify the relative power of cartridges at a glance.

Six Gun

A slang term for a revolver that holds siz rounds. Usually referring to cowboy style revolvers.

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.

Aperture Sight

Also known as peep sights, range from the ghost ring sight, whose thin ring blurs to near invisibility (hence ghost), to target aperture sights that use large disks or other occluders with pinhole-sized apertures. In general, the thicker the ring, the more precise the sight, and the thinner the ring, the faster the sight.

DA

Abbreviation for Double Action

Touchmark

A craftsman's signature stamp, discretely placed to identify his work.

Mag

Slang word for Magazine.

Nipple

A small metal tube extending through the breech of a percussion firearm through which the flame passes from the percussion cap to fire the powder charge.

Eye Relief

The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.