Glossary of Firearms Terms




Also called "ammo", ammunition is a general term used to describe any material fired from a weapon.  Firearm ammunition comes in a variety of sizes and types and is typically designed to work in specific firearms.

Read More (our Ammo Overview page)



The ATF, the Bureau of Alcohol, Tobacco, Firearms and Explosives, is a law enforcement agency in the United States' Department of Justice.  The ATF is tasked with numerous jobs including stopping the illegal use and trafficking of firearms.


Automatic firearm

Automatic firearm is a firearm that automatically feeds ammunition as long as the trigger is depressed.

Read more on our Rifles page


Background Check

Depending on where you live, when you purchase a gun from a licensed dealer, you will undergo a background check using various federal and/or state databases.  These checks determine if you have anything in your background that would prohibit you from buying a gun.  However, if you fall into any of the legally prohibited categories identified on the purchase paperwork, you must not purchase a gun even if you are someone that could pass a background check.  Nor should you even attempt to buy a gun, whether to "see what happens" or for any other reason.



Backstop is anything located behind the target that is intended to stop the bullet after the target is struck.



The barrel of the firearm is the tube through which the bullet is propelled as it leaves the firearm.



A breach-loading firearm, such as a typical shotgun, is designed for ammunition to be loaded via the rear (breech) of the barrel.



Not to be confused with a cartridge, a bullet is the metal projectile that is expelled out of the barrel of the firearm.



Caliber refers to diameter of the hole bored into the barrel of the firearm and the diameter of a bullet.  Calibers are typically measured in millimeters, hundredths of an inch or thousandths of an inch but may not be exact measurements. 

For example, a .357 Magnum and a .38 Special are both considered 38 caliber even though the bullet diameter is actually 357 thousands of an inch.  Each firearm is rated to fire one or more specific calibers.

Most firearms have the caliber for rifles and handguns or gauge for shotguns clearly marked on the barrel or side of the receiver. 

Example calibers:  .22, .380, 9mm, .45, 10mm, .38, .357, 5.56/.223



Not to be confused with a bullet, a cartridge is a single round of ammunition made up of the the entire casing, primer, projectile and powder.


Concealed Carry

Concealed carry, also known as CCW (Carrying a Concealed Weapon), is a term used to describe carrying a firearm in an concealed manner.  It is very important that you understand your state and local laws regarding how you may lawfully carry a concealed weapon and where you may carry the concealed weapon. Many states may require you to obtain a special license before you can carry a concealed weapon.

Alternate Terminology:

  • Carrying a Concealed Weapon (CCW)
  • Concealed Carry
  • Conceal and Carry

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Constitution of the United States

The Constitution of the United States is a document signed by delegates to the Constitutional Convention on September 17, 1787 which established America's national government and the basic rights of its citizens.  We encourage every United States citizen to read their Constitution.

Read the United States Constitution



A derringer is an extremely compact handgun with 2 barrels that has a large bore and is very effective at a close distance.


Double Action

Double Action indicates a type of mechanism within a gun whereby each trigger pull will cock the hammer or firing mechanism and fire a round of ammunition.


Dry Firing

Dry Firing means operating a firearm without ammunition in the chamber.


Open Carry

Open carry, is a term used to describe visibly carrying a firearm in an unconcealed manner in public places.  It is very important that you understand your state and local laws regarding how you may lawfully carry a visible, unconcealed weapon and where you may carry the weapon.




A pistol is a handgun whose cartridge chamber is integrated with the barrel of the gun.  Revolvers are not defined as pistols.

Read more (our Pistol page)



A feature on a firearm that allows aftermarket parts to be mounted beneath or on the side of the firearm.



Unlike pistols whose cartridge chamber is integrated with the barrel of the gun, revolvers have a revolving cylinder containing multiple chambers.  Each chamber holding a single cartridge.  As the revolver is fired, the cylinder rotates moving the next chamber in line with the barrel of the gun.

Read more (our Revolver page)



A rifle is a firearm. typically fired from the shoulder, that has a long spirally grooved barrel to make the bullet spin for greater accuracy over long distances.

Read more (our Rifle page)



Rifling is the process of making spiral grooves in a gun barrel for the purpose of improved accuracy and allowing the bullet to travel longer distances.


Second Amendment

"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

The Second Amendment is one of ten amendments to the U.S. Constitution comprising the Bill of Rights and gives U.S. citizens the right to own and use firearms.

Read the United States Constitution

Read More at the NRA Website



Semi-automatic rifles rely on the gases that are released when a round of ammo is fired to opperate the bolt. That in turn, chambers the next round. With a semi-automatic rifle, you must manually chamber the first round. But after that first round is fired, chambering happens automatically.

Read more on our Rifles page



A shotgun is a firearm designed to fire "shot", small pellet-like projectiles, or "slugs", single solid projectiles.  Shotguns come in a variety of calibers such as 12-gauge and are often single-barreled, double-barreled, or a special combination of barrels.  Shotguns are typically designed for shorter ranges because most lack the special "rifling" that allow a bullet to spin for longer distance travel.  Most shotguns are breach loading.

Read more (our Shotgun page)


Single Action

Single Action indicates a type of mechanism within a gun whereby you must pull back the hammer each time you want to fire a round of ammunition.



Trajectory is the path that a projectile travels from the muzzle to the point of contact.


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