Letter J

The Definition of Jacket

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Jacket

A metal, usually copper, wrapped around a lead core to form a bullet.


19 Other Firearms Definitions You Need To Know


Reactive Targets

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

Knuckle

The curved, forward end of the bar of a break-open firearm's action, about which the mounted forend iron revolves downward. This area should be kept lightly greased to avoid galling the bearing surfaces.

Isosceles Stance

There are two basic variants of the Isosceles stance, the Traditional Isosceles and Modern Isosceles stance. In both Isosceles stances, the feet parallel pointing toward the target and are roughly shoulder width apart. Both arms are stretched almost equally forward with the gun centered forward, creating the triangular shape which gives the stance its name.

Delayed Blowback

A self-loading firearm whose breechblock and barrel are not positively locked together, but which incorporates a mechanism which initially restricts the breechblock from moving when fired, delaying its opening.

Trap Gun

A shotgun, often with only a single relatively-long barrel, with relatively tight choke boring and a relatively high-combed stock used for shooting clay pigeons in the game of Trap, where the birds are launched at least 16 yards ahead, usually rising and going away from the shooter at relatively low angular velocity. To better absorb recoil, a trap gun is normally heavier than a field gun because one shoots a lot but walks only a little.

Cut-Away

A firearm that has had numerous careful machining cuts taken in its exterior with a view to exposing and demonstrating the functioning of critical parts of its mechanism

Beavertail

A large piece of curved metal at the top of the grip on a pistol which protects the user's hand from getting "bitten" by the hammer or slide. It is nearly always the top part of the grip safety commonly found on many 1911-style pistols.

Plinking

Informal shooting at any of a variety of inanimate targets.

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.

Sporting Firearm

Any gun that can be used in a sport.

Crisp Trigger

A trigger that breaks (to release the hammer) easy.

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.

Muzzle Energy

The power of a projectile or a load of shot at the point that it exits the muzzle of a firearm, normally expressed in foot-pounds.

Anson & Deeley Action

A type of internal hammer side by side shotgun boxlock action. It was patented in 1875 and is the essence of simplicity utilizing only two springs and three moving parts (per barrel). One of the most successful action designs ever, and still produced to this day by most SxS shotgun manufacturers.

Iron Sights

The mechanical sighting system which usually comes with the firearm made of metal with no optics.

Pinfire

An early form of complete, self-contained cartridge. It included bullet, powder and ignition primer, all in one package. The primer was located towards the base of the cartridge, but completely internally. The pin, shaped like a little finishing nail, pointed on the inside end and resting on the internal primer, projected radially about a quarter-inch to the outside of the base of the cartridge. When loaded, a pinfire gun showed the tips of the pins exposed through small slots in the tops of the breech faces of the barrels. To fire, hammers fell on the pins, driving them (through the wall of the cartridge) into the internal primer.

Follow Through

Holding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.

Trap

A game of competitive clay pigeon shooting on a formally designed layout. In plan view, one launching machine is located 16 yards in front of a straight line, firing rising targets perpendicular to and away from that line. Five competitors shoot five individual targets at each of five stations along that line. Although each target is presented at slightly randomized vectors, trap emphasizes generally a single type of shot, outgoing and rising, and targets are broken at generally longer ranges than Skeet.

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.