Glossary of Reloading Terms
- Action - The component of a rifle or pistol through which it is loaded, unloaded, and fired.
- Annealing - The process of softening metal through exposure to heat. Annealing can prevent case necks from cracking after repeated resizing.
- Antimony - An element that is used in alloys to increase the hardness of lead.
- Ballistic Coefficient - A measurement of a bullet’s ability to overcome air resistance during flight.
- Barrel Cylinder Gap - The gap between the cylinder and the barrel (forcing cone) of a revolver.
- Bearing Surface - The area of a projectile that comes in contact with the bore.
- Bedding - The fit and stability of a barreled action within a rifle stock.
- Belted Case - A cartridge case with a reinforced “belt” around its base, usually continuing 2-4 mm past the extractor groove.
- Boat Tail - A taper near the heel of a bullet, intended to improve accuracy and trajectory.
- Body - The area of a case between the head and the shoulder.
- Bolt - The piece of a firearm’s action which contains the firing pin assembly, locking system, and extractor mechanism.
- Bore - The hollow area inside the barrel of a firearm.
- Boxer Primer - A type of centerfire ammo that feature only one flash hole and an anvil which is part of the primer itself.
- Brass - A copper/zinc alloy. Often used by handloaders as a term for empty cartridge cases.
- Burning Rate - A term used to describe the relative rate of ignition for a given powder.
- Burr - a rough edge or ridge left on a case by the action of a tool or machine.
- Caliber - The internal diameter of a gun barrel.
- Cannelure - A groove or channel around either a bullet or a cartridge case. This groove is typically used to determine where crimping should occur.
- Cartridge - A complete (typically ready-to-fire) round of ammunition.
- Case - The reusable brass component of a cartridge that acts as a container for the other components.
- Centerfire - A cartridge with a primer located in the center of the cartridge case head.
- Chamber - The section of a gun’s barrel which holds the cartridge before it is fired. The chamber restricts case expansion during firing.
- Chamber Cast - A metal or compound molding taken of a firearm’s chamber to allow accurate measurement of the chamber’s dimensions.
- Chamfer - To remove burrs left by case trimming, usually through reaming or beveling a case.
- Charge - The amount of powder that is loaded into a given case, typically expressed in grains.
- Compressed Charge - A condition in which powder is packed more densely than normal into a case, exceeding the usable capacity of the case.
- Core- The lead center part of a bullet.
- Cylindrical Powder - A tube-shaped, extruded type of smokeless powder.
- Deburr - To remove the rough edges (or burrs) that result from case trimming.
- Decap - To remove a used priming cap from the pocket of a fired case.
- Die (reloading) - A tool used to re-form the brass, resize the brass within specification, and seat and crimp the bullet.
- Die (bullet making) - A tool used to shape and form the bullet.
- Double Base Powder - A smokeless powder that contains a combination of nitrocellulose and nitroglycerin.
- Engraving - The marks left on the surface of a bullet from rifling.
- Erosion - The slow process through which hot powder gases and bullet friction wear away rifling.
- Expander Ball - A piece on the decapping stem that is used to expand the case mouth to the ideal diameter for the bullet.
- Extruder Primer - A ring around the primer indent where the primer has been extruded into the firing pin, typically considered an indication of excessive pressure.
- Fire-Forming - A method of firing a cartridge and achieving a full expansion of the case to the chamber dimensions.
- Flake Powder - A fast-burning, smokeless powder that is typically thin and round in shape.
- Flash Hole - The small opening which allows the primer flash to ignite the powder in the case interior.
- FMJ (Full Metal Jacket) - A hard metal shell, typically copper, that encases a bullet, designed to increase aerodynamics and accuracy.
- Gas - The vapor form of burning powder which expands to create pressure, propelling the bullet.
- Gilding Metal - A common bullet jacket material that is an alloy of copper and zinc.
- Grain - Weight unit used for measuring charges or bullets. 437.5 grains is equal to one ounce.
- Grooves - A spiral cut removed from the bore of a rifle.
- Hangfire - A condition in which the ignition of a rifle is delayed after the strike of a pin.
- Head - The base of a cartridge case beneath the body.
- Headspace - The distance between the head of a cartridge case and the front of the firearm’s bolt (when the case shoulder is against the front of the chamber).
- Ignition - The combustion of the powder caused by the flame of the primer.
- Improved Cartridge - A standard cartridge that has been fire-formed in a specially chambered rifle to modify body taper and shoulder angle, so that it may be used in a specially chambered rifle.
- Ingalls Tables< - A set of ballistic information originally computed by Col. James M. Ingalls.
- Jacket - The outer covering of a bullet that enhances mushrooming and contains the lead core.
- JHP (Jacketed Hollow Point) - A bullet type designed to expand rapidly upon impact. This increases lethality while preventing over-penetration.
- Lands - Raised areas between the grooves inside of a barrel.
- Load Density - The overall weight of a given powder charge. Typically expressed in grains and divided by the volume of the total case.
- Locking Lugs - On a bolt action rifle, these are protrusions that prevent the bolt from moving backward when the firearm is discharged.
- Lock Time - The amount of time between releasing the firing pin and the firing pin hitting the primer.
- Magnum - A cartridge case that achieves greater power than is standard for a given bullet diameter.
- Meplat - The diameter measuring across the blunt section of a bullet tip.
- Mercuric Primer - A type of primer that features mercury in its compound. Mercuric primers are corrosive and have thus fallen out of popularity.
- Metal Fouling - Pieces of metal left by the projectile as it passes through the bore of a firearm.
- Micrometer - An instrument used to measure thickness and/or diameter.
- Misfire - Occurs when a cartridge does not fire after being struck by the firing pin.
- Neck - The narrowest portion of the case that grips around the projectile.
- Neck Reaming - The process by which the case wall thickness is uniformed. Typically done by removing metal from the inside of the case wall.
- Neck Sizing - A method to resize cartridge cases wherein only the neck of the case is altered.
- Neck Turning - Removing metal from the outside of the case wall to create uniform case wall thickness at the neck of the cartridge.
- Non Corrosive Primer - A primer developed with materials that will not corrode or induce rust in the firearm or case itself.
- O.A.L. (Overall Cartridge Length) - A measurement taken from the tip of the bullet to the foot of the case in an assembled cartridge.
- Ogive - The front, curved part of a projectile.
- Pierced Primer - A primer that has been punctured by a faulty firing pin.
- Pressure - Measured in pounds per square inch, this is the force produced by a propellant when it is burned.
- Powder Trickler - A device that dispenses powder one grain at a time.
- Primer - A small metal cup that is struck by the firing pin to create a spark that ignites the powder in a cartridge case.
- Primer Pocket - A small divot in the head of a cartridge case that holds the primer.
- Propellant - A highly combustible substance that creates gas when ignited. Also referred to as “powder”.
- Protruding Primer - A primer that has fallen partially out of its primer pocket.
- Ram - The piece of a reloading press that works to raise or lower the case into the die.
- Rebated Case - A condition wherein a case’s rim is smaller than its body in diameter.
- Rifling - Spiral grooves in the bore of a firearm which cause the projectile to spiral upon exit.
- Rim - The lip located behind the extractor groove on a cartridge case.
- Rimfire - A non-loadable cartridge wherein the priming compound is found under the rim.
- Rimmed Case - A case wherein the rim has a larger diameter than the body.
- Rimless Case - A case wherein the rim is the same diameter as the body.
- Round - An assembled cartridge.
- Round Nose - A blunt-nosed bullet.
- Rupture - A crack or split in the material of the case.
- Seating Depth - The position at which a bullet is seated in the mouth of a case.
- Seating Die - A die used to place a bullet into a case at a specified depth.
- Sectional Density - Expressed as a ratio, the bullet’s pound weight to its inch diameter.
- Semi-Rimmed Case - A case wherein the rim is just a little larger than the body.
- Shank - The straight portion of a projectile, found immediately behind the bullet’s ogive.
- Shellholder - A device that holds the case (or shell) as it is inserted into a given die.
- Shoulder - The sloped area of a case between the neck and the body.
- Single Base Powder - A powder, typically smokeless, made of nitrocellulose.
- Spherical Powder (Ball Type) - Smokeless powder that has been shaped into small round grains. These can be flat or round.
- Spent Primer - A primer that has already been fired or otherwise used.
- Swaging - A process that uses large amounts of pressure to shape an object.
- Throat - The section of a firearm ahead of the chamber. The throat is usually not rifled.
- TMJ (Total Metal Jacket) - A type of bullet wherein the entire surface of the projectile is covered with a copper plating.
- Twist - A measurement representing the rate of spiraling inside the barrel of a rifle.
- Velocity - The speed, typically expressed in FPS, of a projectile in flight.
- Virgin Brass - A case that has never been fired.
- Web - The small piece of a cartridge between the primer pocket and the interior of the case.
- Windage - The small adjustment of a firearm’s sight (typically horizontally) that aligns the point of aim with the point of contact.