Common Firearm Terms

• Action – The action is the part of a firearm that loads, fires, and ejects the cartridge.

• AFTE – AFTE stands for the Association of Firearms and Tool Mark Examiners.

• Ammunition – Ammunition is the cartridges that include a primed case, propellant, and projectile.

• Barrel – The barrel is the metal tube that a projectile moves through after firing.

• Base – The base is the part of the cartridge case that houses the primer.

• Ballistics – Ballistics is the study of a moving projectile after it leaves the barrel of a firearm.

• Black powder – Black powder is an older type of gunpowder that contained nitrate, charcoal, and sulfur.

• Bolt – The bolt is the supporting mechanism on some firearms that has a firing pin, extractor, and possibly an ejector.

• Bore – The bore is the inside of the barrel.

• Brass – Brass is a slang term that refers to fired cartridge cases.

• Breech – The breech is the end of the barrel that attaches to the action.

• Breech face – The breech face sits around the firing pin.

• Buckshot – Buckshot is the pellets typically loaded in shotshells.

• Bullet – Bullets are the projectiles that eject from firearms.

• Bullet wipe – The bullet wipe is the area around a bullet hole that happens due to bullet lubricant, lead, smoke, and debris.

• Butt – The butt is the part of the firearm that you hold or place against the shoulder.

• Caliber – The caliber is the diameter of the bore, typically expressed in hundredths of an inch.

• Cannelure – The cannelure is the groove around the circumference of a bullet, used for crimping, lubricating, and identification.

• Cartridge – A cartridge is a unit of ammunition that includes the cartridge case, primer, powder, and bullet.

• Cartridge case – The cartridge case is the container for all of the components that make up a cartridge.

• Centerfire – The centerfire is the center of the case head of the cartridge.

• Chamber – The chamber is the part of the action that holds the cartridges.

• Choke – The choke is the inside constriction of the shotgun bore, situated at the muzzle and designed to control the pattern of fired shots.

• Class characteristics – Class characteristics are the features of a specimen that indicate the restricted group source.

• Clip – A clip is a separate cartridge container used to quickly reload a firearm magazine.

• Cock – To cock a firearm is to place the firing mechanism under spring tension to fire it.

• Comparison microscope – A comparison microscope features two microscopes that are connected to an optical bridge, enabling the user to view to objects at the same time with the same magnification.

• Cylinder – The cylinder is the part of a revolver that holds the ammunition.

• Discharge – Discharging a firearm is firing it.

• Double-action – A double-action trigger cocks the hammer and fires it.

• Ejector – The ejector of a firearm ejects the cartridge.

• Extractor – The extractor of a firearm withdraws a cartridge from the chamber.

• Firearm – A firearm includes the action and barrel, used to discharge a projectile.

• Firearms identification – Firearms identification is a discipline of forensic science that determines if ammunition was fired from a specific firearm.

• Firing pin – The firing pin strikes the primer of a cartridge to initiate ignition.

• Firing pin impression – The firing pin strikes the cartridge case, causing an indentation.

• Forensic science – Forensic science is the scientific examination of physical evidence, used in courtrooms.

• Gauge – Gauge describes the diameter of a shotgun barrel.

• Griess test – The Griess test is a test to detect nitrites, which are residues that collect around bullet holes.

• Grip – The handle of a shotgun is the grip.

• Gunpowder – Gunpowder is the powder used in ammunition as the propellant charge.

• Gunpowder residue – The unburned gunpowder is left behind as a residue.

• Gunshot residue – All of the residues from firing a firearm collect as residue.

• Hammer – The hammer strikes the firing pin to detonate the gunpowder.

• Hammer block – The hammer block keeps the firing pin and hammer separated as a safety mechanism.

• Headstamp – The headstamp consists of numbers, letters, and symbols and is stamped on the head of a cartridge case to identify where it was made.

• Individual characteristics – Individual characteristics are marks produced by using tools, which distinguish tools from other tools.

• Ignition – Ignition involves lighting gunpowder.

• Lands and grooves – Lands are the raised areas between grooves inside the barrel.

• Magazine – The magazine stores cartridges for a repeating firearm.

• Magnum – The magnum is a type of cartridge with more powder, which increases the energy of the fired bullets.

• Muzzle – The muzzle is the end of the barrel where the bullet exits.

• Pellet – Pellets are small, round projectiles.

• Pistol – A pistol is another name for a handgun.

• Powder – Powder is the propellant in a cartridge.

• Primer – The primer is the explosive material that ignites when struck.

• Projectile – The projectile is the item that is propelled by the firearm.

• Pyrodex – Pyrodex is a brand name of a type of black powder.

• Recoil – The recoil is the backward movement that happens after firing a firearm.

• Reload – Reloading a firearm involves reassembling the components.

• Receiver – A receiver is a type of firearm that includes the firing and breech mechanism.

• Revolver – A revolver is a handgun with a cylinder that has holes to hold the cartridges.

• Rifle – A rifle is a firearm that is fired from the shoulder.

• Rifling – Rifling describes the spiral grooves inside a gun barrel that make the bullets spin.

• Rimfire – Rimfire describes the primer distribution around the periphery of the base of the cartridge.

• Round – The military refers to cartridges as rounds.

• Safety – The safety on a firearm prevents firing.

• Shotgun – A shotgun is a long gun fired from the shoulder.

• Shotshell – A shotshell is a cartridge designed to be fired from a shotgun.

• Sights – Sights on top of a barrel help with aiming.

• Silencer – A silencer can fit onto the muzzle of a firearm to muffle the sound it makes when firing.

• Single-action – A single-action hammer has to be manually cocked every time before pulling the trigger.

• Slug – A slug is a single projectile in a shotshell.

• Smokeless powder – Smokeless powder is the modern gunpowder that smokes less than black powder.

• Sodium Rhodizonate test – This test detects particulate lead or lead vapor around a bullet hole.

• Stock – The stock is the frame that holds the barrel and action.

• Striation – Striation is the parallel contours caused by force and motion.

• Submachine gun – A submachine gun is a short-barreled automatic firearm.

• Tool – A tool is any object used for a mechanical advantage.

• Toolmark (impressed) – An impressed toolmark is the impression left behind after placing a tool against a hard object.

• Toolmark (striated) – A striated toolmark is the mark left behind after moving a tool against and across a softer object.

• Trajectory – Trajectory describes the curved path of a projectile between muzzle and target.

• Trigger – The trigger is the firearm mechanism that the user moves to discharge the firearm.

• Wad – The wad is assembled and placed into the head end of the shotshell.

This list provided by A Glossary For Firearms: All Terms and Gun Lingo Explained (snipercountry.com)