Letter B

The Definition of Breech Pressure

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Breech Pressure

The amount of rearward force exerted by the propellant gases on the bolt or breech of a firearm action or breech when a projectile is fired. The applied force has both magnitude and direction, making it a vector quantity. This is also known as Bolt Thrust on firearms that are Bolt Action

19 Other Firearms Definitions You Need To Know

Break Action

A firearm whose barrels are hinged, and rotate perpendicular to the bore axis to expose the breech and allow loading and unloading of ammunition.


The angle of the butt of a gun in relation to the line of sight. Pitch is measured by resting the gun with its butt flat on a floor, the top of the receiver against a wall and its muzzle pointing up. The distance of the muzzle from the wall is the gun's pitch down.

Low Kneeling

A shooting position in which one or both knees are touching the ground and the shooter is as low as possible.


A person who can shoot up to the mechanical capability of their weapon.

Articulated Front Trigger

A spring-loaded hinged front trigger on a dual trigger side by side or over under shotgun, built to cushion its impact on one's trigger finger as the gun recoils when the rear trigger is pulled.

Magazine Follower

Same as Follower. A plate, mounted to the top of a spring, inside a magazine, over which cartridges may slide smoothly as they are guided into the chamber of a repeating firearm.

Failure To Extract

A semi-automatic firearm malfunction in which the extractor fails to move the empty case out of the way as the slide travels back. A failure to extract often causes double-feed malfunction.


A piece of tooling used to form a sequence of uniform parts through the use of heat and/or pressure; especially, in firearms terminology used to form brass cartridge cases accurately to their correct size for reloading.


To prepare or charge a muzzle loader for firing.

Rolling Block

Helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy.


The substance which imparts movement to the projectile in a firearm. In a firearm, usually powder. In an airgun the propellant is air or Co2


A rifle with a relatively short barrel.

Light Machine Gun

A machine gun that is designed to be carried and opperated by a single person.

Slide Catch

Sometimes also known as a slide lock, slide release or slide lever. On a semi-autmatic gun, the lever or catch that holds the slide open (after the last round is fired or when racking an empty gun). Typically they are located on the left side of the frame about mide barrel. Some of the newer semi-automatic pistols have an internal slide lock. Even though on pistols with an external slide catch, you can push down on the lever to release the slide, it should never be used in such a manner. The proper way to release the slide is to rack the slide.

Shooting Sticks

A pair of slender and easily-carried wooden dowels or sticks, which when held, crossed, in the fingers of the left hand while also supporting the forend of a rifle, usually shooting offhand, provides somewhat enhanced stability for a more accurate shot.


Also spelled blueing. A passivation process in which steel is partially protected against rust, and is named after the blue-black appearance of the resulting protective finish. True gun bluing is an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe3O4), the black oxide of iron, which occupies the same volume as metallic iron. Bluing is most commonly used by gun manufacturers, gunsmiths and gun owners to improve the cosmetic appearance of, and provide a measure of corrosion resistance to, their firearms.

Needle Gun

A needle gun is a bolt-action firearm (the first known type of bolt action rifle) that has a needle-like firing pin, which can pass through fully self-contained (paper) cartridge case to strike a percussion cap at the bullet base. The first experimental needle gun was designed by Jean Samuel Pauly, a Swiss gunsmith, in 1812. The first mass-produced needle gun was invented by the German gunsmith Johann Nicolaus von Dreyse, who, beginning in 1824, had conducted multiple experiments, and in 1836 produced the first viable breech loading gun model using a complete cartridge .

Sight Picture

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

Minute Of Angle

A 1/60th part of a degree, the unit of measure used in adjusting rifle sights. As it turns out conveniently, a minute of angle translates almost exactly to one inch at 100 yards (actually 1.047 inches), to two inches at 200 yards and three inches at 300 yards