Letter T

The Definition of Turn-Bolt Action

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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.


19 Other Firearms Definitions You Need To Know


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.

Follower

A smooth, sometimes contoured plate, within a magazine, at the top of a spring, across which cartridges slide when being loaded into a chamber.

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.

Lockplate

A metal plate on which the firing mechanism is mounted on percussion and earlier firearms.

Cylinder

The part of a revolver that holds cartridges in separate chambers radially around a central hingepin. The cylinder revolves as the handgun is cocked, , either to the left or to the right depending on the gun maker's design, bringing each successive cartridge into position, and locked into alignment with the barrel for firing.

Receiver

The housing for a firearm's breech (portion of the barrel with chamber into which a cartridge or projectile is loaded) and firing mechanism. In semi-automatic handguns and revolvers, this part is typically called the frame.

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.

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.

Sights

The device that aids the eye in aiming the barrel of a firearm in the proper direction to hit a target.They can be a mechanical, optical, or electronic device. Iron sights or sometimes as open sights, consist of specially-shaped pieces of metal placed at each end of the barrel. The sight closest to the muzzle end of the gun is called the front sight, while the one farthest from the muzzle (and nearest to the shooter) is called the rear sight.

Straddle Floorplate

A hinged plate covering the bottom of a rifle magazine and extending rearward on either side of the triggerguard. This design allows it to be more securely fastened for one more imperceptible step towards total reliability.

Sight Picture

What the shooter sees when looking through the sights at the target.

Stripper Clip

Simple clips made of metal or sometimes plastic that hold several rounds of ammunition in a row and is used to quickly fill a magazine.

BATF

Short abbreviation for the Bureau of Alcohol, Tobacco, Firearms and Explosives

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.

Obturation

The process of a bullet expanding under pressure to fit the bore of the firearm, or a cartridge case expanding under pressure to seal the chamber.

Thumb Safety

An external, manual safety which is typically disengaged with the firing-hand thumb.

Trigger Group

The entire collection of moving parts which work together to fire the gun when the trigger is pulled. It may include trigger springs, return springs, the trigger itself, the sear, disconnectors, and other parts.