Letter T

The Definition of Trajectory

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Trajectory

The arc described by a projectile (or a load of shot) after it exits the muzzle of a firearm. Falling objects accelerate downwards at a rate of 32 feet per second, per second. The faster a projectile travels, the greater the distance it can cover in a given time before dropping too far. Hence, the higher the velocity of a bullet, the flatter the trajectory it will achieve.


19 Other Firearms Definitions You Need To Know


Ricochet

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

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.

Hook

A concave, semi-cylindrical surface cut into the forward lump of a barrel set of a break-open firearm which revolves about the hinge-pin when the gun is opened.

DA/SA

Abbreviation for Double Action/Single Action. A type of firearm that is designed to operate in double action on the first shot, and in single action on the second and subsequent shots.

Small Bore

Generally refers to a .32 calibre or smaller firearm.

Speed Strip

A flat piece of rubber which holds revolver cartridges preparatory to loading them into the revolver's cylinder. Similar to a moon clip

Drop-Box Magazine

An extra-deep magazine typical of large calibre rifles for dangerous game. The line of the underside of the wrist does not carry straight forward as with ordinary rifles. Rather the rear of the magazine aligns more towards the center of the forward edge of the triggerguard, typically allowing at least one extra cartridge to be carried.

Submachine Gun

A fully automatic firearm that fires pistol ammunition.

Floor Plate

The detachable plate at the bottom of the cartridge magazine.

Blowback

A semi-automatic firearm whose breechblock and barrel are not mechanically locked together when fired. In such case the breechblock immediately begins to separate from the barrel upon firing. Blowback is used in comparatively low powered weapons, in which inertia of the breechblock, and cartridge wall adhesion against the chamber, are sufficient enough to retard opening until breech gas pressures have fallen to a safe level.

COF

Abbreviation for Course of Fire.

Modern Isosceles

In the Modern Isosceles stance, the feet are roughly shoulder width apart, with the gun-side foot closer to the target than the off-side foot. The knees are flexed, and the entire body leans slightly toward the target. The shoulders are closer to the target than the hips, and the hips are more forward than the knees. The shoulders are rotated forward and the head, rather than being upright, is vultured down behind the sights. The entire body thus has an aggressively forward appearance, and is poised to move quickly if necessary.

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.

Cartridge

The assembly consisting of a bullet, gunpowder, shell casing, and primer. Cartridges also include shotgun shells and black powder packets used in muzzle loading guns.

Wad

A felt, paper, cardboard or plastic disk that is used in a shotshell. Also in muzzle loading, a piece of cloth used to seal the bullet in the barrel. It's purpose and function is the same as a shotgun wad.

Casehardening

A heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle. The parts to be casehardened are packed in a crucible with carbon-rich media such as bone meal and charcoal, heated to bright orange, about 1800F, then quenched in bubbling oil. Also called Carbonizing.

Double-Base Powder

A rapidly burning powder made by absorbing nitroglycerine into nitrocellulose (guncotton).

Clay Pigeon

Originally, live pigeons were used as targets, but they were gradually replaced with clay disks and ultimately banned. Later clay has been replaced with more suitable raw materials.

Hornady Magnum Rimfire

A type rimfire rifle cartridge developed by the ammunition company Hornady. .17 Hornady Magnum Rimfire (4.527mmR), commonly known as the .17 HMR, was developed in 2002. It descended from the .22 Magnum by necking down the .22 Magnum case to take a .17 caliber (4.5 mm) bullet.