Letter B

The Definition of Bore

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Bore

The tunnel down the barrel of a firearm through which the projectiles travel.

  • A smooth-bore firearm is one that does not have rifling on the barrel's internal surface.
  • A big-bore firearm is one that fires a large caliber.
  • A small-bore firearm is one that fires a small caliber.


19 Other Firearms Definitions You Need To Know


Slide Bite

A phenomenon which is often grouped with hammer bite. In this case the web of the shooting hand is cut or abraded by the rearward motion of the semi-automatic pistol's slide, not by the gun's hammer. This most often occurs with small pistols like the Walther PPK and Walther TPH that have an abbreviated grip tang. This problem is exacerbated by the sharp machining found on many firearms.

Frangible

A bullet that is designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the danger behind the intended target. Examples are the Glaser Safety Slug and the breaching round.

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.

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.

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.

Underbolts

A sliding bar, running longitudinally through the watertable of a break-open side-by-side gun's action, with openings through which the lumps of the barrels pass when the gun is closed. Under spring tension, this bar moves forward when the opening control is released and its two locking surfaces engage complementary slots (bites) in the rear of the two barrel lumps. Originally operated by a hinged tab in front of the trigger guard. Now invariably operated by a cam from Scott's [toplever] spindle. Most modern side-by-side guns lock closed in this manner.

Smokeless Powder

The propellant powder used in modern ammunition. It is not an explosive, but rather a flammable solid that burns extremely rapidly releasing a large volume of gas. Commonly called "gunpowder" and usually made from nitrocellulose, or nitrocellulose and nitroglycerin. It is classified as a "Flammable Solid" by the Department of Transportation.

Selective-Fire

A firearm's ability to be fired fully automatically, semi-automatically or, in some cases, in burst-fire mode at the option of the firer.

Open Tip Match

A rifle projectile made with the tip of the bullet open as a means of increasing accuracy as compared to standard military bullets that are made with a closed tip and an open base. The are not designed to expand like a hollow point bullet but may fragment.

Crown

The area inside the bore nearest to the muzzle.

Telescopic Sight

An optical sight, offering some magnification, often variable, with some kind of adjustable aiming grid inside (a reticle), which when mounted on a firearm, usually a rifle, makes sighting easier.

CFL

Abbreviation for Concealed Firearms License.

Casket Magazine

A quad stack box magazine.

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Bore Snake

A bore snake is a tool used to clean the inside (bore) of the barrel of a gun. It resembles a short section of rope with a smaller, weighted cord attached to one end to help feed the bore snake through the barrel. A bore snake often has one or more integrated brushes to help clean the barrel, and may also be used to apply lubricant. It is an alternative to using a cleaning rod and patches to clean the barrel of a gun. Bore snakes are made in different sizes for different calibers and gauges of guns.

Single Action

An action type that when the trigger is pulled, the only thing the trigger does is drop the hammer (or striker). This applies to both revolvers, semi-automatic and automatic guns. On a single action revolver, the gun must be manually cocked before it can be fired. With semi-automatic and automatic guns that are single action, the only thing the trigger does is drop the hammer, striker or firing pin onto the cartridge. Then the firearm is cocked again when from the recoil of the fired round. A firearm that the gun is cocked and the hammer drops when the trigger is pulled is a double action gun.

Lockplate

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

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.

Bore Diameter

The measurement from one side of the bore to the other. In a rifled barrel this means measurement of the bore before the rifling grooves are cut.