Letter T

The Definition of Twist

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Twist

The length, within a rifled barrel, required to accomplish one full rotation. 1:12 Twist, means a bullet passing down the bore would complete one revolution in twelve inches. 1:7 Twist, means a bullet passing down the bore would complete one revolution in seven inches, which makes it a tighter twist than 1:12. Different weights of bullet require appropriate rates of twist.


19 Other Firearms Definitions You Need To Know


Short Recoil

A semi-automatic pistol in which the barrel and breechblock are locked together for only a short distance of rearward recoil travel, at which point the two are uncoupled, the barrel is stopped and the breechblock continues rearward, extracting the spent casing from the chamber. Upon returning forward, the breechblock chambers a fresh round and forces the barrel back into its forward position. Most modern recoil operated semi-automatic pistols use short recoil.

Out of Battery

A semi-automatic is said to be out of battery when the slide fails to come all the way forward again after the gun has fired. This condition can be created by a misfeed, a dirty gun, weak springs, the shooter's thumbs brushing against the slide, riding the slide, or any of several other causes.

Drop Safety

A mechanical safety that prevents a gun from firing when it is unintentionally dropped.

Primer Ring

Refers to a visible dark ring created by the primers in centerfire ammunition around the firing pin hole in the frame after much use.

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.

Timing

The proper adjustment of the various interrelated moving parts of a gun so that every operation works in proper sequence, such as that the two ejectors of a double gun kick out the spent cases at the same instant and with the same force.

Jacket

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

Blank

A type of cartridge for a firearm that contains gunpowder but no bullet or shot. When fired, the blank makes a flash and an explosive sound (report). Blanks are often used for simulation (such as in historical reenactments, theatre and movie special effects), training, and for signaling (see starting pistol). Blank cartridges differ from dummy cartridges and snap caps, which are used for training or function testing firearms; these contain no primer or gunpowder, and are inert.

Doughnut Pattern

A shotgun pattern with a hole in the middle generally caused by the interference of the top wad.

Pistol Grip

The handle on a pistol. Can also refer to a vertical grip behind the trigger on a rifle.

Chain Gun

A type of machine gun or autocannon that uses an external source of power to cycle the firearm.

Naked Bullet

A bullet not covered by a metal jacket or patch.

Holdopen Toplever

A catch built into the receiver of a break-open gun to keep the toplever in its extreme right position when the barrels are removed. This device makes it slightly easier to remount the barrels. As the barrels are mounted and the breech closed, the barrels contact some kind of release pin (marked with the arrow) and the toplever automatically returns to the center locked position. Because, however, it requires a separate act to find and to depress this tiny tab to re-center the toplever on a broken-down gun, this feature may be irritating when trying to put a gun away in its case.

Shot

In shotgunning, multiple pellets contained in the shell and sent downrange when the shotgun is fired.

Reactive Targets

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

FFL

Abbreviation for Federal Firearms [Dealer's] License.

Frame

The common part of a handgun to which the action, barrel and grip are connected.

Negligent Discharge

The unplanned discharge of a firearm caused by a failure to observe the basic safety rules, not a mechanical failure of the gun.

Jump

The amount of change in the bore axis, measured both vertically and horizontally, while the projectile moves from the chamber to the muzzle when it is fired.