Glossary

A type of cartridge whose bullet diameter is much smaller than the body diameter of the casing in which it rests.

To align the sights by sighting through the bore. When mounting a scope, it will get you close so it takes less time to sight in the rifle.

The diameter of the inside of the barrel after boring, but before rifling. In shotguns, for instance, the smaller the gauge of the firearm, the larger the bore diameter. 

This is an imaginary line that runs through the center of a handgun's barrel and out through the back of the gun. Different handguns have a different bore axis--either a high axis (above the hand) or a low axis (near the hand)--a high bore axis tends to create greater recoil and more muzzle flip when firing the gun than does a low bore axis.

Derived from the process used to make a barrel, this term refers to the interior of the gun barrel. A special drill is used to carve a hole inside a solid bar stock to make the bore. It can also be used to describe some sizes of shotgun shells.

This is a type of action that fires one round at a time. After the bullet is fired, the empty shell is unloaded by the user manually pulling back on the bolt before loading another round into the chamber.

A metal, cylinder-shaped mechanism that holds the cartridge in place during the firing process. In some firearms, it's manually moved by the shooter by pulling back on the bolt handle, thereby ejecting the cartridge.

A bullet designed to give the shooter heightened accuracy based on its design of a tapered base that creates remarkably less drag as it travels through the air.

Browning Machine Gun, i.e. 50 BMG is the .50 machine gun.

Bluing or black oxidizing is a process of treating a gun barrel or other steel parts by creating a thin protective coating around it. It works by turning rust into black iron oxide. The metal attains a dark blue or nearly black appearance, which protects the barrel of the gun.

Blowback is a system of operation for autoloading firearms that obtains energy from the motion of the cartridge casing as it is pushed to the rear of the firearm by expanding gas created at the ignition of the discharge.

In other words, the only thing holding the breech closed on a blowback-operated gun (in battery position) is the recoil spring.

As the name suggests, there is no bullet in a blank. Instead, the round is loaded with black powder so the gun will still fire. Blanks are often used on film and TV sets, to start a race, and for military training.

Referred to as the original gunpowder, which was composed of charcoal, saltpeter and sulfur, whereas today's gunpowder is more refined and generally smokeless.

Blackpowder also produces a lot of smoke in comparison.

Also known as gunpowder, black powder differs from smokeless powder because it creates a larger amount of smoke when ignited. It’s also less powerful than smokeless powder and produces more fouling.

This type of ammunition is usually associated with shotguns, specifically for bird hunting. Birdshot shells are filled with pellets of different sizes for different applications as projectiles, ranging from the smallest diameters .08 inches for simple target shooting, up to 00 Buckshot pellets, which are approximately .36-inches in diameter.