Glossary of Firearms Terminology

  • Action
    Working mechanism of a firearm.  There are various types. Bolt
    Action, Lever Action, Single Action, Double Action, etc.
  • Automatic
    A machine gun.  Any repeating firearm that automatically
    ejects, chambers and
    fires rounds repeatedly, usually at high speed,  with a
    single, steady pull of the trigger. Also
    called Fully Automatic.
  • Backstrap
    The back of a pistol’s frame, the back of the grip.
  • Ball
    A type of bullet or projectile.  Usually used in older
    firearms such as a flintlock, musket-type weapons.
  • Barrel
    The strong metal tube of a firearm through which the bullet
  • Barrel-Cylinder Gap
    The clearance between the sides of a bullet and the bore of the barrel
    as the bullet travels down it when fired.  In the US, the
    industry-standard tolerance of the Barrel-Cylinder Gap is from 0.0001
    to 0.012 inches.  A gap any larger will cause problems with
    firing and accuracy.
  • Black Powder
    Gunpowder.  Explosive mixture
    consisting of charcoal, sulfur and saltpeter (nitrate).
    Invented by the
    Chinese in ancient times.
  • Blank or Blank Cartridge
    A cartridge that has the explosive powder charge but no projectile.
  • Blowback (Blowback-Operated)
    Utilization of the force of hot, expanding
    gases released from firing the firearm.  In modern firearms,
    strong force of the blowback is used to eject spent cartridges and a
    spring recoil replaces them with new ones in the
    chamber.  Also called “gas operated.”
  • Blued or Blueing
    The treatment of metal on firearms that results in a black or
    bluish-black finish, usually done with chemicals.
  • Blunderbuss
    Precursor to the shotgun.  Usually a flintlock weapon, shorter
    than a
    rifle or a carbine, longer than a pistol, that is identifiable by a
    large, flared funnel-like barrel.  Used for short-range
    close-in fighting, often used on ships as well as by mail and
    stagecoach drivers.  Also called a naval or pirate
    blunderbuss.  Used from late 1600s to mid 1800s.
  • Bolt
    Metal bar or rod that slides and seats and/or removes a cartridge.
  • Bolt-Action
    Firearm’s action, using a manual sliding and/or rotating bolt to
  • Bore
    The inside of the barrel, or other part that needs to be hollowed out.
  • Breech
    The rear of the barrel.
  • Breech Loader
    A firearm that is loaded at the rear of the barrel.
  • Buckhorn Sight
    An open-top sight with curved sides.  Probably so-named
    because the shape  resembles antlers on a buck.
  • Bullet
    Technically, the projectile portion of a cartridge that is blown off by
    detonation of the powder charge, and flies through the air toward the
    target, leaving the shell or casing behind to be ejected.
    People often refer to the entire cartridge as a
    “bullet.”  On older black powder or percussion firearms, the
    bullet was just a shaped piece of lead.
  • Butt
    The very rear end of a rifle stock or the bottom of a pistol grip.
    In the Old West, the butt of a rifle or pistol was used as a
    secondary weapon by lawmen to  subdue troublemakers.
    Very handy for cracking skulls!  Sometimes referred
    to as “pistol whipping.”
  • Buttplate
    On a rifle, a covering of metal, wood, plastic or other material fitted
    onto the very rear end of a rifle butt.
  • Caliber
    Interior diameter of the barrel, or the bore.  Also
    corresponds to the size of ammunition that will fit in it.
  • Carbine
    A rifle or musket with a short barrel, usually a military version.
  • Cartridge
    A modern “bullet” or metal casing, which is an entirely self-contained
    piece of ammunition, with projectile, powder charge and ignition
    primer, all in one unit.  Nowadays, there are mainly only
    kinds of cartridge: rimfire, centerfire and shotgun.
  • Centerfire
    A cartridge that is detonated by striking a primer button centered in
    its base by the firing pin.  If a cartridge has what appears
    be a “button” in its base end, it’s a centerfire cartridge.
  • Chamber
    The rear of the barrel, or part of the gun where the ammunition is
    placed, in position, ready to fire.
  • Checkering
    The crosshatched pattern or texture on a metal, wood or plastic surface
    of a firearm, usually used to improve grip, or for decoration.
    Especially used on hammers and slides and grips.
  • Choke
    The shaping or an attachment at the muzzle of a shotgun that directs
    the spray or  pattern of shot as it is fired
  • Clip
    A container or feeding system, usually spring-loaded, that holds
    cartridges in place, so that it can be inserted into a firearm’s
    magazine.  Sometimes, the clip is called a “magazine” or a
    removable magazine.
  • Compensator
    A variation of muzzle brake that diverts escaping high-pressure gases
    upwards at the muzzle, reducing the general upward kick caused by
    recoil to compensate for it, and improve accuracy.
  • Crowning
    The rounded or beveled end surfacing of the barrel opening, (muzzle)
    used to
    protect the opening and edges.
  • Cylinder
    On a revolver, the rotating “wheel” that holds the cartridges, and
    allows them to rotate into position with the chamber for
  • Damascus Barrel
    On old black powder firearms, a type of barrel made usually of separate
    bands of twisted iron. If you have a firearm with a Damascus barrel, it
    is not considered safe to shoot due to age, and the fact that such
    construction will not withstand the stresses and pressures created by
    today’s ammunition.
  • Deringer, Derringer
    Originally a brand of very small pocket pistol made for easy
    concealment.  Today, the term Deringer or Derringer (2 R’s) is
    used to
    refer to just about any brand of very small and concealable pocket
  • Double Action
    A pistol or revolver that allows the hammer to be cocked and released
    by pulling the trigger.
  • Dry Fire, Dry Firing
    Pulling the trigger and sending the firing pin and other parts into
    their full range of motion and impact without using
    ammunition.  Usually considered a bad thing to do,
    placing undue stress on the parts.
  • Extractor
    Mechanism that removes empty ammunition casings from the chamber so
    they can be ejected clear of the firearm.
  • Firing Pin
    A strong metal rod or pin that forcefully strikes the primer of a
    cartridge, firing the firearm.
  • Flash Suppressor
    Attachment (or integral part of the muzzle) that covers the end of the
    muzzle, hiding the flash created by firing a firearm.
  • Flintlock
    Old form of ignition for firearms in the days before fully
    self-contained cartridges.  A locking mechanism with a metal
    part that strikes a flint, producing a spark, firing the weapon.
  • Frizzen
    On a flintlock firearm, a curved metal plate, usually
    hinged, which is struck
    by the hammer, which contains
    a flint. When the flint strikes the frizzen, it creates a shower of
    sparks, while springing open to expose them to the powder in the pan to
    ignite it.
  • Fully Automatic or Full Automatic
    A machine gun.  Any repeating firearm that automatically
    chambers and fires rounds repeatedly with a single, steady pull of the
    trigger.  Also called Fully Automatic.
  • Gas-Operated
    Utilization of the force of hot, expanding
    gases released from firing the firearm.  In modern firearms,
    strong force of the blowback is used to eject spent cartridges and a
    spring recoil replaces them with new ones in the
    chamber.   Also
  • Gauge
    The inside diameter or bore of a shotgun barrel.  A shotgun’s
    gauge is determined by a formula of how many balls of shot taken from a
    pound of metal will fit in a certain bore size.
  • Grain
    Measurement unit of a powder charge.  One pound is equivalent
    to 7,000 grains of powder.  437.5 grains is equivalent to one
  • Grip
    The handle of a revolver or pistol.  Sometimes fully
    integrated, or mounted in pieces.  Can be wood, metal,
    plastic, etc.
  • Grooves
    Spiraled channels cut into the inside of a firearm’s barrel, that cause
    a bullet to spin upon firing, stabilizing its trajectory and improving
  • Half-Cock
    Partially cocking a firearm’s hammer so that it does not fall and set
    off the firearm.  If you slip and let the hammer fall while a
    round is chambered, you
    will discharge the firearm.
  • Hammer
    Moving part that hinges up on rear (on hammer-equipped firearms), and
    snaps back into place with force, detonating the cartridge.
    Flint-tipped hammers are also used on flintlocks, to strike
    the frizzen to ignite powder.
  • Hangfire
    A malfunction in the primer of a cartridge that causes a delay in
    firing after the trigger is pulled.  Obviously, if you have a
    long or ongoing hangfire or misfire, DO NOT look into the barrel to see
    on.  Some people have actually (stupidly?) died doing this!
  • Hollowpoint
    Bullet with a hollow area in the nose, that causes it to expand on
    impact, increasing its destructive force.
  • Jam
    Misfire, caused by a mechanical part malfunction, or by a cartridge
    being stuck midway in the magazine or chamber. Also, almost any other
    kind of mechanical blockage in the firearm.
  • Lands
    Inside the barrel of a riflled firearm, the raised areas of the metal
    that remain above the cut rifling grooves.
  • Magazine
    Spring-loaded container that feeds cartridges into the firing
    chamber.  Detachable or non-detachable. Sometimes
    called a “clip.”
  • Magnum
    A longer version of a cartridge of the same
    caliber.  The increased length is to accommodate more powder
    increased velocity, power and range.
  • Mainspring
    On a flintlock musket or rifle, a strong spring that holds the hammer
    back in the cocked position until released by pulling the trigger.
  • Misfire
    When a cartridge fails to discharge, or to discharge properly.
  • Musket
    A smoothbore barrel (no rifling) firearm.  Usually an old
    firearm with a flintlock firing system.
  • Musketoon
    Short barrel, smoothbore, muzzle-loading carbine.  A
    short-barrel version of a musket.  Similar to a carbine.
  • Muzzle
    The end of the barrel, the  opening where the bullet exits.
  • Muzzle Brake
    Attachment or shaping at the muzzle to dissipate or reduce gas pressure
    in order to reduce recoil.
  • Muzzle Energy
    The force (measured in foot-pounds) of a bullet exiting the muzzle.
    Similar to recoil.
  • Muzzle Loader
    Firearm that is loaded through the muzzle, with a solid
    breech.  Old smoothbores are muzzle loaders.
  • Pan
    On a flintlock musket or rifle, a small bowl-shaped pan that holds a
    charge of powder. When
    ignited by the flint striking the frizzen, it flashes down a drilled
    hole in barrel, igniting the main charge in the barrel.
  • Parabellum
    General name given to cartridges measuring 9 X 19mm.  Also the
    popular nickname  of a famous German Pistol in that same
    caliber, made by
    Deutsche Munitions Fabrik (DWF) beginning in the early 1900s.
    Parabellum is a latin word (si vis pacem, para bellum) meaning: “If you
    wish for peace, prepare for war”
  • Parkerizing
    A dull gray or greenish finish on a firearm to prevent rust.
  • Patchbox
    On a musket or flintlock rifle, a small compartment in the stock,
    usually with a door or lid, used
    for storing patches of greased or oiled cloth, which is rammed down
    the barrel, and used to wad or pack the
    lead ball or bullet against the powder, providing a seal for better
    compression upon firing.
  • Peep Sight
    Rear sight with a small hole, which one peeps through to line up on the
    front sight and the target.
  • Percussion Cap
    On older “Cap and Ball” or percussion revolvers, a small, explosive
    cap, usually placed on a “percussion nipple” that, when struck by the
    hammer, ignites the powder charge through a small hole, firing the
  • Percussion Revolver
    An older black powder revolver, in which the hammer strikes a
    percussion cap, igniting the main powder charge.
  • Pinfire
    Old, obsolete cartridge with a small
    pin protruding from the side, near the base, that when struck by the
    firing pin, ignites the main powder charge.
  • Plinking
    Old and obsolete type of cartridge
    that had a small metal pin sticking out of the side, at the base, which
    when struck, would ignite the charge, firing the bullet.
  • Primer
    Small charge in a cartridge that ignites the powder when struck by the
    firing pin, discharging it.
  • Receiver
    The part of a firearm that contains the moving parts, or the action. In
    modern firearms, the mechanical area that loads and ejects a cartridge.
  • Recoil
    The energy created by the explosive release of discharging a firearm,
    that pushes it back against the person shooting it. It can range from a
    gentle bump to a smashing, bone-jarring experience, depending on the
    firearm.  Remember what physicist Albert Einstein
    said?  “For every action, there is an equal and opposite
  • Revolver
    A firearm with a rotating cylinder that holds cartridges, and aligns
    them for loading, unloading and firing.
  • Rifle
    Long-Barreled firearm with a rifled groove cut into the bore of the
  • Rifling
    The grooves cut into the bore of a barrel, to cause the bullet to
    rotate when fired, improving stability and accuracy in flight.
  • Rimfire
    A cartridge that has its primer in the base, and is ignited by having
    the firing pin strike the edge (rim) of the casing, crushing the rim to
    ignite it.  Modern rimfire cartridges are mainly found only in
    small calibers, such as .22 caliber.
  • Round
    Informal way of saying “cartridge” or a shot.  Example; “I
    fired a couple of rounds at them.”
  • Sabot or Sabot Bullet
    In firearms, sabots are
    only known to be used in old black powder guns.  A sabot is
    basically an adaptor that fits onto the back end of a bullet, to help
    trap in gases for more compression, enabling a smaller bullet to be
    used in a firearm with a larger bore or caliber.
  • Safety
    A locking catch or mechanism that prevents the trigger from being
    pulled, or
    otherwise prevents the firearm from being discharged.
  • Sear
    Pivoting part of the action of a firearm connecting the trigger to the
    hammer and holding it in place until released by the trigger.
  • Selective Fire
    Feature of a firearm that allows firing either on full-automatic, or
    semi-automatic mode, usually with the use of a switch or
  • Semi-Automatic
    A firearm that automatically extracts and ejects spent cartridges upon
    firing, then
    re-chambers a new one to be fired, and can repeat this action, one
    pull at a time, until the magazine or clip is empty.  This
    action takes place very rapidly.
  • Shot
    Small metal balls, grapeshot or buckshot, used in shotgun
    cartridges.  Shot comes in different sizes.
  • Shotgun
    Firearm with a smoothbore barrel, used to fire buckhot or shot.
    Modern shotguns use brass-based plastic cartridges filled
    with shot.
  • Single Action
    Firearm that requires the hammer to be manually cocked before pulling
    the trigger. On a single-action semi-automatic, you only need to cock
    the hammer before firing it for the first round, until it’s reloaded.
  • Sight
    Blade or protusion with a notch in it, usually on both the rear of the
    firearm and on the front, above the muzzle, to allow the shooter to
    line them up with the target.  There are many different types
    of sights.
  • Silencer or Silenced
    Device attached to the muzzle of a firearm to muffle or reduce the
    sound of firing.
  • Slide
    On firearms (usually semi-automatic pistols) the top part of the action
    (usually the entire top of the pistol) that ejects and loads the
    chamber by pulling it back, sliding it back
    along the frame.
  • Spitzer
    A bullet with a pointed nose
  • Stock
    The long part of a firearm (usually a rifle or musket) held by the
    shooter, or braced against the shooter’s hip or shoulder, to stabilize
    during firing.  Can be wood, polymer, metal etc.
  • Submachine Gun
    Automatic firearm that uses pistol ammunition.  Usually a
    smaller version of a full-size machine gun.  Used for
    close-range firing.
  • Take Down
    Button, lever or other device that allows for quick disassembly of a
    firearm for cleaning, oiling and maintenance, transportation etc.
  • Tang
    Protusions on the frame or receiver that connect it to the stock or the
  • Top Strap
    Top part of the frame on a revolver.
  • Wildcat Cartridge
    Non-standard cartridge.

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