Please PM SkipD with any additional topics or other changes you would like to see in this glossary.
Basic Loading Terms
Handloading - The process of loading ammunition by hand. This term is often interchanged with "reloading", however the term "handloading" can be applied when using all new components while the term "reloading" should only be used when using previously fired cartridge cases.
Reloading - The process of loading ammunition using previously fired cartridge cases. This process can be done by hand or by machine. When cartridges are reloaded using automated machinery, the term "remanufactured" is sometimes applied to the product.
Firearm Terms
Bore - The uniform-sized hole through a firearm's barrel between the chamber and the muzzle. See also: Bore Diameter.
Bore Diameter - The dimension from land-to-land inside a rifled barrel or the inside diameter of a smooth-bored barrel. See also: Groove Diameter and Caliber.
Caliber - The approximate internal diameter of a firearm's barrel or the approximate diameter of the projectile fired through it. In the United States, it is common to use the groove diameter as the caliber while elsewhere in the world, the bore diameter is used. Caliber for handheld firearms is typically expressed in inches (such a .22, .30, .45, etc.) or millimeters (such as 5.56, 7.62, etc.) and this holds true for large firearms such as artillery though the numbers would be much larger.
Centerfire - Also written as center-fire. A cartridge design that has the primer located in the center of the cartridge's base. Modern centerfire primers are replaceable and are either Boxer or Berdan types. Centerfire and rimfire ammunition cannot be substituted in the same firearm without some sort of adapter. See also: Rimfire.
Chamber - The portion of a firearm's barrel (or the cylinder in a revolver) which is shaped to accept and hold a cartridge. Revolvers have multiple chambers. A cartridge must be securely held in the chamber when it is fired.
Chamber Pressure - The pressure created by firing a round in a firearm (either in a metallic cartridge or any other method of loading a firearm with smokeless or black powder). This pressure is what drives the bullet through the barrel. Generally, chamber pressure is defined as the peak pressure achieved when the charge is ignited. Values are usually stated as CUP (Copper Units of Pressure) or PSI (Pounds per Square Inch). There are several ways of measuring chamber pressure, but very few hobby shooters have appropriate equipment to do so. While the typical handloader cannot measure chamber pressure, the deformation of the primer can often be "read" to ensure that pressures from his/her load are not exceeding normal pressures for the caliber. This is done by comparing the primer deformation to that of commercial loads that have had chamber pressure measured.
Clip - A device that holds ammunition but does not have any feeding mechanism as part of the device. This term is often incorrectly applied to a sister device, the magazine. See also: Magazine.
Crown - Special machining of a firearm's barrel muzzle opening to provide and protect perfectly uniform rifling edges all the way around the bore. This is important so that all bullets from the barrel can fly the same way, minimizing spread at the target.
Freebore - The space in a barrel between a chambered bullet's ogive and the beginning of the rifling in the barrel.
Groove - The spaces that are cut out (or formed in different ways) between the lands in a rifled barrel. See also: Groove Diameter and Land.
Groove Diameter - The dimension from groove to groove inside a rifled barrel. See also: Bore Diameter and Caliber.
Headspace - The dimension from the face of a firearm's bolt to the point in the firearm's chamber where the cartridge positively contacts the chamber to position the cartridge. Some cartridges headspace on a rim. Most straight-walled auto pistol cartridges headspace on the mouth of the cartridge. Bottlenecked cartridges most often headspace on a particular part of the shoulder. Some magnum rifle cartridges headspace on a belt.
Land - The raised portions in a rifled barrel which impress their shape into a bullet and force the bullet to rotate while traversing the barrel. Grooves separate the lands in a rifled barrel. See also: Groove.
Magazine - A device that holds ammunition and has a feeding mechanism (usually a spring and a follower or similar devices) as part of the device. Magazines may either be built into a firearm or be removable from the firearm. The term "clip" is often incorrectly applied to magazines. See also: Clip.
Muzzle - The opening of a firearm's barrel where the fired bullet exits on its way to the target. See also: Crown.
Rifling - The twisted combination of grooves and lands within a rifled barrel. The purpose of the rifling is to rotate the bullet so that it is stabilized while in flight. Rifling twist rate in small arms is typically defined as "1 turn in so many inches", for example.
Rimfire - A cartridge design that has the primer in the rim of the cartridge's base. The most common modern rimfire cartridge is the .22 rimfire family which is made in several different lengths (.22 Short, .22 Long, and .22 Long Rifle are the most common). See also: Centerfire.
Bullet Terms
Ball - A term, typically used by the military, describing a full metal jacket bullet with no opening at the nose of the bullet's jacket. This term is used both for round-nosed bullets (usually for pistols) and pointed bullets (usually for rifles). The common understanding is that "Ball" ammunition is using solid or non-expanding bullets.
Boat-tail - A bullet design feature consisting of a tapered base, narrowing toward the trailing end of the bullet. The purpose of the boat-tail design is to reduce drag. Boat-tail bullets are typically used in rifles rather than in handguns.
Bullet - The projectile which is driven toward a target when the cartridge is fired. Note that, while it is not uncommon for people (generally unfamiliar with firearms) to call a complete loaded cartridge a "bullet", this is incorrect. "Bullet" and "Cartridge" are NOT synonyms.
Cannelure - A groove around a bullet. The purposes for the groove are for holding a lubricant (usually for a lead bullet) and/or to accept the crimped mouth of the cartridge case to keep the bullet from changing its position in the cartridge case.
Hollow point - A bullet design feature where the center of a bullet's forward tip is opened ("hollow"). There are many variations of this design, but the general purpose is to enhance mushrooming of the bullet after it impacts a (usually live) target.
Jacket - A gilding metal (a copper/zinc alloy) cup that covers the outside surfaces of a bullet. A bullet's jacket may be open at the base or at the nose of the bullet depending on the intended design of the bullet.
Ogive - The outer profile of a bullet - typically a pointed curved shape - between the cylindrical body and the tip of the bullet.
Round nose - A bullet design feature where the center of a bullet's forward tip is rounded. This shape can be applied to a lead bullet or a jacketed bullet. A round nose jacketed bullet is often referred to as a "hard-ball" bullet, particularly in military lingo.
Cartridge Terms and Components
Anvil - Part of a primer system against which the pressure-sensitive explosive is compressed when the primer's cup is indented by the firearm's firing pin. The anvil is a part of a Boxer primer assembly while the anvil for a Berdan primer is actually part of the cartridge case.
Belt - An enlarged ring, typically about 2mm to 4mm wide around the base of a cartridge case, starting at the forward edge of the extractor groove. This belt is usually seen on a large magnum rifle case such as that for the .300 Winchester Magnum. The purpose of the belt is for positive headspacing with a rimless cartridge.
Berdan (primer) - A primer type with the explosive mixture contained in a small metal cup with no anvil included. The anvil is actually a part of the cartridge case, centered between two or three flash holes. Because of the flash hole configuration in the cartridge case, Berdan primers cannot be removed with a conventional primer punch in a decapping die. Hydraulic primer removers can be used and there are special mechanical tools available to pry spent Berdan primers from the case. See also: Boxer.
Bottlenecked - One of several basic cartridge case shapes. In a bottlenecked case, the neck is significantly smaller in diameter than the body of the case and the neck is separated from the remainder of the case by a tapered shoulder.
Boxer (primer) - A primer type contained in a small metal cup with the anvil contained in the cup along with the explosive mixture. See also: Berdan.
Brass - An alloy consisting of approximately 70% copper and 30% zinc which is used to make most cartridge cases. Though cartridge cases are also made of steel or aluminum, groups of cartridge cases are commonly called "brass".
Bullet - The projectile which is driven toward a target when the cartridge is fired. Note that, while it is not uncommon for people (generally unfamiliar with firearms) to call a complete loaded cartridge a "bullet", this is incorrect. "Bullet" and "Cartridge" are NOT synonyms.
Cartridge - An assembled self-contained combination of a cartridge case, powder, a primer, and a bullet (and possibly other components). A cartridge (of the proper caliber, of course) can be inserted into a firearm and then fired. A loaded cartridge is often called a "round". A loaded cartridge is sometimes incorrectly called a "bullet" by people who are generally unfamiliar with firearms.
Cartridge Case - The metallic container designed to hold powder, primer, and bullet. Each cartridge case is shaped and sized for a particular caliber. Cartridge cases for centerfire ammunition have primer pockets and flash holes (and anvils when Berdan primers are used) in their bases. Cartridge cases generally have some sort of rim for the firearm's extractor to pull on when extracting the fired cartridge case. Though cartridge cases are most often made of brass, they are also made of steel or aluminum. Groups of cartridge cases are commonly called "brass" regardless of the material they are made of.
Flash Hole - A hole in a centerfire cartridge case between the center of the primer pocket and the chamber where powder is loaded. This hole allows the flame from the primer to ignite the powder. Cartridge cases with Berdan primers usually have two flash holes - one on either side of the anvil and some cases have three holes.
Gas Check - A gilding metal (copper/zinc alloy) cup that fits over the base of a lead bullet. The purpose is to better seal hot propellant gasses and also to minimize leading of the firearm's barrel. Gas checks are generally used for higher velocity lead bullet loads.
Neck - The portion of a cartridge case that holds the bullet. Typically, this term is only used for bottlenecked cartridge cases.
Powder - The explosive chemical propellant used in most firearm cartridges. Black powder, often called gunpowder, and smokeless powder are the two primary categories of powder. There are many types of each category of powder, each designed to burn at a specific rates and pressure ranges.
Primer - A pressure-sensitive explosive device, usually contained in a small metal cup, which ignites the powder in a cartridge after it is struck with the firearm's firing pin. Two common types of primers for centerfire cartridges include Boxer primers and Berdan primers. Rimfire cartridges have the priming material injected into the rim of the cartridge and these cannot be reloaded. Note that there are different sizes of centerfire primers and they must be chosen for the primer pocket size in the cartridge to be loaded.
Primer Pocket - A cylindrical depression in the base of a cartridge case where a primer is mounted. The design of the primer pocket is different for use with Boxer and Berdan primers.
Round - A term that is synonymous with a single loaded cartridge.
Shoulder - The tapered portion of a bottlenecked cartridge case that separates the main body of the case from the neck.
Loading Tasks
Belling - Opening the mouth of the cartridge case slightly into a "bell" shape with a special die in a loading press so that a bullet can be more easily inserted. This is done most often when lead bullets are used.
Charging - The process of inserting the correct amount of powder into a primed cartridge case. The measurement of the powder charge can be done several ways - using a fixed volume scoop, using a calibrated powder measure, or measuring each charge on a scale.
Crimping - Squeezing the opening of the case into the side of the bullet for additional retention as compared to a non-crimped case. This is done either with a combination seating/crimping die or a separate crimping die in a loading press.
Decapping - Removing the primer from a cartridge case. This is usually done with a decapping die in a loading press.
Deburring - Removing metal burrs or rough edges from a cartridge case's mouth, primer pocket, or the flash hole.
Neck sizing - Reshaping only the neck of a fired cartridge case, usually using a press and a neck sizing die, to re-form the neck to standard dimensions while leaving the body of the case formed to fit a particular firearm's chamber. Neck sizing is typically done for maximum accuracy and is normally done only when using a bolt-action rifle. See also: Resizing.
Priming - Installing a fresh primer into an empty cartridge case. This can be done with a variety of tools - some handheld and others using a loading press. A previously fired cartridge case must be decapped and resized as a minimum preparation before priming.
Resizing - Reshaping a fired cartridge case, usually using a press and a full-length sizing die, to re-form the entire case to standard dimensions. Resizing a cartridge case can only be done with brass and nickel-plated brass cases. See also: Neck Sizing.
Seating - Inserting a new bullet into a cartridge case and ensuring that it is pushed into the case at the correct depth, resulting in the proper overall length of the cartridge.
Loading Press Types
Progressive Press - Progressive loading presses have places for more than one die to be mounted at the same time. They also have a rotating multi-position shell holder system. With the typical autoindexing progressive press, each time the operating arm of the press is cycled, the shell holder advances one step, placing a cartridge under the next die station. Thus, each cartridge in the shell holder gets a different function performed on it during the operating arm stroke. Every stroke of the handle finishes assembly of another cartridge.
Single-Stage Press - Single-stage loading presses have a place for only one die. While most single-stage presses are typically bolted to a sturdy bench for operation, there are handheld single-stage presses such as the Lee Breech Lock Hand Press which do not mount to a bench.
Turret Press - Turret loading presses have places for more than one die to be mounted at the same time. The turret design typically requires manual rotation to choose (index) the die to be used.
Loading Dies
Carbide Resizing Die - Functionally, this type of die is the same as the Resizing Die with the exception that the section that does the full-length sizing consists of a carbide ring instead of hardened steel. The carbide sizing ring will last a lot longer than a steel sizing ring. A significant advantage of a carbide resizing die (especially for pistol cartridges) is that lubrication of the cartridge cases before sizing is usually not necessary with the carbide sizer.
Crimping Die - A die which crimps the mouth of the cartridge case to hold the bullet securely. The most common crimping die is a taper crimp die, used mostly on straight-walled pistol cases for autoloading pistols which headspace on the case mouth.
Decapping Die - A die which only removes spent primers. The method is typically the same as the decapper found in most resizing dies, but on occasion one wants to remove spent primers without resizing the cartridge case. Decapping dies are typically sized so that one die can handle a variety of cartridge case sizes.
Expander Die - A die which expands the mouth of the cartridge case in a slight bell shape. This is most often used for pistol cartridges when loading lead bullets. Jacketed bullets seldom require belling of the case mouth.
Neck Sizing Die - A die which sizes only the neck of a cartridge case. The main body of the cartridge case is left as-fired so that it fits the chamber (usually of a particular bolt-action rifle) more precisely than a factory-dimensioned cartridge case.
Resizing Die - A die, most often made of hardened steel, which is used to squeeze an expended cartridge case back to its original design size, typically over its full length. Many resizing dies also include a punch (a decapper) to remove the expended primer from a cartridge case. The decapper may also have an expander button that expands the cartridge case mouth to the exact diameter needed to hold the bullet.
Seating Die - A die that is used to align a bullet with the cartridge case and then insert (seat) the bullet to the required depth. The depth setting is adjustable. Seating dies are sometimes provided with more than one seating plug, each shaped for a particular bullet style. Seating dies often are made to be able to provide a roll crimp of the case mouth into a cannelure around the bullet.
Other Loading Tools and Accessories
Bullet Mold - A device having cavities that are shaped like a bullet. Molten lead alloy is poured into the mold. Once hardened (by cooling), a sprue cutter is knocked aside with a rod or stick to trim the bullet before ejecting it from the mold.
Bullet Luber/Sizer - A special press that, along with an appropriate die and top punch and bullet lubricant, sizes a cast lead bullet to a precise diameter and squeezes lubricant (such as Alox or beeswax) into lube grooves in the bullet.
Case Trimmer - A tool consisting of a cutter with a mandrel, and a shell holder which is used to trim the length of a cartridge case. Case trimmers are available as purely manual tools (by Lee, for example) and as bench-mounted tools which may be manually or electrically operated.
Loading Block - A device, typically made of plastic or wood, that can hold up to 50 or 60 cartridge cases during the loading process. This is extremely convenient when charging powder to the cases. Also, with the charged cases still in the loading block, one can visually scan all the cases after charging powder to determine that all are properly filled with powder.
Lubricating Pad - A pad, very similar to a stamp pad, which is charged with case lubricant. Cleaned fired cartridge cases are rolled across the pad to lubricate them prior to full-length resizing. Other tools typically used with a lubricating pad include a brush to put lubricant inside the neck of the cartridge case and possibly an applicator of some sort to lubricate the necks of bottlenecked cartridge cases.
Powder Funnel - A special type of funnel that will create a seal over the mouth of an empty cartridge case while pouring powder through it into the case.
Powder Measure - A device that is used to "throw" consistent powder charges typically using a calibrated cylinder in a rotating frame. The cylinder is positioned under a powder supply hopper for filling and then rotated downward to dump the charge to the cartridge case. There are other types of powder measures with a removable measuring cylinder (such as the very fine but now obsolete Belding & Mull powder measure). Setting up an adjustable powder measure requires the use of an accurate powder scale.
Primer Pocket Cleaner - A small tool that can be inserted into a primer pocket and then rotated to clean the carbon and other debris out of the primer pocket.
Primer Pocket Reamer - A tool that can be inserted into a primer pocket and then rotated to cut the edges of the primer pocket to remove primer crimping from the cartridge case.
Primer Pocket Swager - A tool that can be inserted into a primer pocket (typically with a press) to re-form the edges of the primer pocket to remove primer crimping from the cartridge case. The re-forming with a swager does not remove any material as is done with a primer pocket reamer.
Reamer - A tool with a set of tapered cutters that can be rotated to smooth the inside of a cartridge case mouth edge, the outside of a cartridge case mouth edge, or a primer pocket. Most reamers are handheld tools. There are many variations of reamers available for reloading.
Measurement Tools and Terms
Cartridge Case Gauge - A tubular gauge which has its interior shaped like the chamber of a firearm for a specific caliber. The purpose is to be able to determine that the shape of a cartridge will properly fit a standard chamber for the caliber.
Chronograph - A device used to measure the velocity of a bullet (usually in feet per second) shortly after it leaves the muzzle of a firearm. A chronograph is a very valuable tool for determining some of the characteristics of a loaded cartridge as it is fired. Using the chronograph to measure the velocity of several loaded cartridges from a batch can help to determine the repeatability of the particular load.
Grain - The weight unit most often used in measurement of powder and bullets. One gram equals 15.432 grains. One pound equals 7000 grains.
Scale (powder and/or bullet) - A weighing device for accurately measuring the weight of a powder charge or a bullet. Both purely mechanical and electronic scales are available. A good scale should be considered a mandatory tool for loading cartridges. A scale is critically important for setting up an adjustable powder measure.
Please PM SkipD with any additional topics or other changes you would like to see in this glossary.