Letter O

The Definition of Obturation

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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.


19 Other Firearms Definitions You Need To Know


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.

Mortar

An artillery piece used to fire shells over short ranges at very high trajectories.

Firearm

A firearm is a portable gun (pistol or rifle), being a barreled weapon that launches one or more projectiles often driven by the action of an explosive force.

Flat Nose

A bullet shape with a flat nose rather than a rounded one.

Holographic Weapon Sight

a non-magnifying gun sight that allows the user to look through a glass optical window and see a cross hair reticle image superimposed at a distance on the field of view. The hologram of the reticle is built into the window and is illuminated by a laser diode.

Elevation

The setting on the sights of a firearm that controls the vertical placement and the altitude above mean sea level. This is important for long range precision shooting because the air density changes with elevation and affects the path of the bullet.

Pistol Grip

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

Slug

More correctly a "rifled slug" or "shotgun slug." An individual cylindrical projectile designed to be discharged from a shotgun. The term is often incorrectly used to mean a Bullet.

Underwater Firearm

A firearm specially designed for use underwater.

Quadrail

Sometimes spelled Quad Rail. First conceived and sold by Knights Armament Company in the mid 90s when Reed Knight saw soldiers duct taping flashlights to their handguards in news footage of Panama, the quad rail has become almost a standard item found on most military rifles. Quad rails allow easy attachment of accessories which aid tactical shooters, such as lights, infrared lasers, foregrips, sling attachment points, and secondary sighting systems. However, nowadays, any full length forearms on an AR, with or without rails may also be refered to as a Quadrail.

Trigger Break

The point at which the trigger allows the hammer to fall, or releases the striker, so that the shot fires. The ideal trigger break is sudden and definite. "Like a glass rod" is the cliche term shooters use to describe the ideal crisp, clean break.

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.

Pair

Two shots fired very quickly with the use of the sights.

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.

Long Gun

Another term for rifle.

Gas Port

A small hole in the barrel of a gas-operated firearm through which expanding gases escape to power the autoloading system.

Lockplate

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

Bullet Trap

A type of backstop that catches the fired bullet and prevents it from exiting the area. Bullet traps are most commonly used on indoor ranges.

Printing

Is when the outline of the concealed handgun may be discerned through the outer clothing.