The Glossary of Industry terms has been compiled by SAAMI’s Technical Committee to facilitate technical interchanges between members of that committee. It is not intended to provide legal definitions of the terms included, and, in light of further experience, the definitions of these terms may change. It is not intended to be comprehensive since it does not cover the full range of the diversity of the sporting arms and ammunition industry’s products. It is, in other words, a working draft that, it is hoped, may be useful in addressing certain technical matters frequently considered by the Technical Committee and is subject to further change and refinement.
It was the committee’s decision that ONLY industry terms would be included which are unique to the firearms and ammunition industry directly. Optical terms have been omitted for the most part. Common metallurgical terms were not included because they are not unique to the industry. Where there is a common term with a usage unique to our industry, it has, however, been included.
1. A term used to designate the specific cartridge(s) for which a firearm is chambered. 2. Firearms: The approximate diameter of the circle formed by the tops of the lands of a rifled barrel, often expressed in hundredths of an inch (“.38 Caliber”) or millimeters (“7mm Caliber). 3. Ammunition: A numerical term included in a cartridge name to indicate a rough approximation of the bullet diameter.
A type of lock found in certain breechloaders, such as the 1873 Springfield. See Trap Door Action.
Related Terms: TRAP DOOR ACTION
1. A circumferential groove generally of corrugated appearance cut or impressed into a bullet or cartridge case.
Also Known As: Grooves, Lube Groove
The tipping or tilting of a gun to one side at the time it is fired.
1. An obsolete term referring to a primer. 2. Percussion Muzzle Loading: See Percussion Cap.
Related Terms: PERCUSSION CAP
CAP AND BALL
A muzzleloading firearm using the percussion cap ignition system.
The ignition of a primer or percussion cap produces a high temperature flash of hot gases, which is called the Cap Flash. Also called Primer Flash.
Also Known As: Primer Flash
Consists of a standard lead type bullet having a harder metal jacket (gilding metal, copper, etc.) over the nose.
A device that contains a quantity of percussion caps and simplifies the placement of the cap upon the nipple on a muzzle-loading firearm.
A rifle of relatively short length and light weight originally designed for mounted troops.
A thin card-like disc placed over a shot load or powder. See Overpowder Wad.
Related Terms: OVERPOWDER WAD
A lifting mechanism in some repeating firearms that raises and positions the cartridge for feeding into the chamber. Sometimes called the Lifter.
Also Known As: Lifter
A repeating action firearm component which engages or is attached to the carrier or lifter and acts to control its motion. Sometimes called Lifter Pawl.
Also Known As: Lifter Pawl
A simplified version of a sling, used for carrying purposes only.
Also Known As: Strap
A single round of ammunition consisting of the case, primer and propellant with or without one or more projectiles. Also applies to a shotshell.
A flat container having blind holes into which cartridges can be inserted in an upright position to be readily available to the shooter.
A copper alloy with a nominal composition of 70 percent copper and 30 percent zinc. “Cartridge Brass” is the trade name for the Copper Development Association, Inc. Alloy C26000.
The main body of a single round into which other components are inserted to form a cartridge. Usually refers to centerfire and rimfire cartridges. Serves as a gas seal during firing of the cartridge. Usually made of brass, steel, copper, aluminum or plastic. Also referred to as a shellcase.
Also Known As: Shellcase
CARTRIDGE CASE LENGTH
The dimensions from face of the head to the mouth.
Also Known As: Case Length
A separate cartridge container to hold cartridges or shells in proper sequence for feeding into a specific firearm. It is a magazine charger, and unlike a magazine does not contain a feeding spring. Sometimes improperly called a Magazine.
The firing of a cartridge by extreme overheating in a firearm chamber, without operation of the firing mechanism. Usually associated with machine guns.
Also Known As: Cook-Off
A firearm component which acts as a guide for the cartridge while it is being fed from the magazine to the chamber.
Surface in the receiver or barrel of a repeating action firearm along which the cartridge rides in feeding from magazine to chamber.
Also Known As: Feed Ramp
1. A mechanical device in firearms that allows only one shell to feed from the magazine with each cycle of the action. 2. A manually-operated device to prevent the feeding of cartridges from a magazine.
Also Known As: Shell Stop, Cartridge Cutoff, Shell Latch
CARTRIDGE, SMALL ARMS
A term used by the US Department of Transportation as defined by US Code of Federal Regulations (49 CFR 173.59): https://www.ecfr.gov/cgi-bin/text-idx?SID=bd5856259cccd9bf739fb6f683c1d2af&mc=true&node=se49.2.173_159&rgn=div8
Refers to cartridge case or shotshell case. Shortened through common usage to simply “case.”
Total available internal volume of a case when a primer is seated in the primer pocket.
CASE EXTRACTOR GROOVE
An annular groove cut in rimless, semi-rimmed cartridge or belted cases, forward of the head, for the purpose of providing a surface that the gun extractor may grip to remove the case from the chamber.
A procedure used by handloaders to change the external shape of a cartridge case somewhat by firing in a gun having a chamber of the desired configuration. The case to be fireformed must be dimensionally similar to the desired configuration, especially in the case head area.
Also Known As: Fire-Form
A fixture used to inspect cartridge case dimensions (i.e. length, diameters, thickness, etc.) to insure conformance to established tolerances.
CASE HEAD EXPANSION
An enlargement of the cartridge case head diameter on firing.
An expression of the number of times a case can be reloaded and fired.
The opening in the case into which the projectile or shot is inserted.
CASE MOUTH CHAMFERING
A manual operation performed on cartridge cases prior to reloading to ease insertion of projectiles or chambering. Can be internal and/or external.
The angled or tapered section of a bottleneck cartridge case connecting the main body of the case to the smaller diameter neck.
A longitudinal rupture in the wall of a cartridge case or shotshell.
Also Known As: Split Case
The elongation in the body of a cartridge case during firing.
The gradual reduction in diameter of a cartridge case from head to shoulder or mouth.
A devise used to remove material from the case mouth in order to shorten the case to within the max and min specification for that particular case.
Ammunition that has the propellant charge attached to the bullet and not enclosed in any type of cartridge case.
A bullet formed by pouring molten lead alloy into a mold.
The buttstock of a firearm which has neither cast-on or cast-off relative to the centerline of the barrel.
The offset of the butt of a shoulder-fired firearm to the right for a right-handed shooter and to the left for a left-handed shooter. See Stock Dimensions.
Also Known As: Cast
The offset of the butt of a shoulder-fired firearm to the left for a right-handed shooter and to the right for a left-handed shooter. See Stock Dimensions.
Also Known As: Cast
The act of forming an object, such as a bullet, by pouring molten material into a mold.
A low velocity caliber 22 rimfire cartridge having a conical bullet (“CB”) loaded in a case shorter than the 22 short.
CENTER OF IMPACT
The center of a shot pattern or bullet impacts on a target made by a series of rounds fired at the same aiming point.
Any cartridge intended for use in rifles, pistols and revolvers that has its primer central to the axis in the head of the case.
A cartridge initiator which is assembled central to the axis of the head of the cartridge case and which is actuated by a blow to the center of its axis, as opposed to a rimfire primer, which must be struck on the circumference of the cartridge head.
1. In a rifle, shotgun or pistol, the rearmost part of the barrel that has been formed to accept a specific cartridge or shell when inserted 2. In a revolver, the holes in the cylinder that have been formed to accept a cartridge.
A low melting point material or alloy casting made of a chamber to determine internal chamber dimensions.
The conical transitional zone of the chamber between the forward end of the casemouth, or free-bore if present, and the end of the taper into the rifling.
Also Known As: Throat, Ball Seat
That pressure created in the chamber of a firearm by the expanding propellant combustion gases. Normally measured by means of a piezoelectric pressure transducer or a copper crusher.
Also Known As: Breech Pressure
One of a series of cutting tools used to form the chamber area of a barrel bore.
1. The amount, by weight, of a component of a cartridge (i.e., priming weight, propellant weight, shot weight.) 2. To load a firearm.
A diamond-like pattern in the wood, plastic or metal components of a firearm for improving grip or ornamentation.
A frame having vertical end supports between which a gun stock may be held while its gripping surfaces are being checkered.
CHECKERING LINE COUNT
A method of expressing the size of the diamonds in a checkering pattern, expressed in lines per inch The higher the number, the finer the pattern; the lower the number, the coarser.
The tools used for cutting a checkering pattern in wooden stocks. May be hand or machine powered.
A raised part of the side of the stock of a shoulder-arm against which the shooter rests his face.
Also Known As: Cheek
A tool used to cut the precise bullet configuration into the two halves of a bullet mold.
Lead Shot containing more than 0.5% alloying metal to increase its hardness. Also called Hard Shot.
Also Known As: Hard Shot
An interior constriction at or near the muzzle end of a shotgun barrel for the purpose of controlling shot dispersion.
While no choke marking standard exists, typical choke markings are (in order from greatest to least constriction):
Full Choke = F, Full, * or I
Improved-Modified = IM, Imp. Mod., ** or II
Modified = M, Mod, *** or III
Improved Cylinder = IC, Imp. Cyl., **** or IIII
Skeet = SK, Skeet
Skeet USA = SK USA
Cylinder = CL, Cyl.
Some firearm manufacturers in the Europe also use the United States system.
A replaceable insert in the muzzle of a shotgun barrel to provide the desired amount of choke.
A type of lump which is integral with the barrel. See Lump.
Related Terms: LUMP
An instrument designed to measure elapsed time. When correlated with distance it is used to determine projectile velocity.
A circular, domed, frangible disc used as an aerial target for shotgun shooting games. Originally formed out of clay, modern “clay” targets are generally made from a formulation of pitch and limestone. Dimensions and weights are regulated by skeet and trap shooter’s associations. Also called Clay Bird or Clay Pigeon.
Also Known As: Clay Bird, Clay Pigeon
Lead bullet, having a thin coating of another material such as brass, copper, nylon, etc.
To place the hammer, firing pin or striker in position for firing.
Any device to indicate that a firearm hammer or striker is cocked.
A mechanical means of cocking the hammer or striker of some firearms using a manually operated, external lever.
COCKING ON CLOSING
In relation to bolt action firearms, when the striker is cocked by closing the bolt.
COCKING ON OPENING
In relation to bolt action firearms, when the striker is cocked by lifting the bolt handle.
1. In certain firearms, the end of a long firing pin or striker by which the firearm may be manually cocked. 2. An internal portion of the cocking mechanism, which holds the firing pin or striker in it’s cocked position against the sear.
A mechanical means of cocking the hammer of some firearms.
Small lug in the cocking mechanism of a firearm.
COEFFICIENT OF FORM
A numerical term indicating the general profile of a projectile.
Also Known As: Form Factor
In a shoulder arm, the ridge at the upper forward part of the butt stock just in back of the grip section.
A multiple barrel firearm designed to fire different calibers or types of ammunition.
The chemical reaction of a fuel and oxygen, usually initiated by a heat source. In the context of interior ballistics, the result of this reaction is gas and heat generation, increasing pressure in an enclosed space.
A copper alloy with a nominal composition of 90 percent copper and 10 percent zinc. “Commercial Bronze” is the trade name for the Copper Development Association, Inc. Alloy C22000. It is used in the manufacture of bullet jackets. See also “Gilding Metal.”
A muzzle attachment or feature to redirect propellant gases with a goal of reducing muzzle lift.
A design of piezoelectric transducer system in which the sensing end matches the internal curvature of the chamber.
A design of piezoelectric transducer system in which the sensing end matches the internal curvature and taper of the chamber.
Also Known As: Transducer, Piezoelectric Pressure
COPPER CLAD STEEL
A laminated structure of copper and steel used for the manufacture of certain bullet jackets.
COPPER JACKETED BULLET
A bullet having an outer jacket of copper or copper alloy, and containing a lead alloy core.
A priming mixture that contained compounds of chlorine and oxygen generally used in military ammunition made before 1952. The residues are hygroscopic and, therefore, promote rusting.
A radial rupture of the head and rim of a rimfire cartridge or shotshell.
The part of a solid frame revolver on which the cylinder is swung out to accomplish loading and ejecting.
Also Known As: Yoke
A trigger that releases without sensible movement.
CROSS BOLT SAFETY
A type of manual firearm safety operated by a lateral force on a button usually located in the trigger guard. Also called Push-Button Safety.
Also Known As: Push Button Safety
1. A transverse operating type of lock used in some break-open type firearms (sometimes called a “Greener Crossbolt”). 2. A device intended to prevent stock splitting due to recoil. 3. A form of manual safety which operates transversely to prevent or permit firing of a gun.
The generally irregular grain pattern common to a stock blank cut from the crotch of a tree.
A feature on the muzzle of the barrel that is concentric and perpendicular to the bore axis. The purpose is to promote accuracy and protect the rifling at the muzzle.
Also Known As: Muzzle Crown
The act of applying a crown.
Related Terms: CROWN
A calibrated metallic cylinder that, when used in conjunction with specific associated equipment, measures chamber pressure or firing pin indent.
CUP (COPPER UNIT OF PRESSURE)
A pressure value determined by means of copper crusher cylinders using SAAMI recommended procedures and equipment.
A longitudinal split in the sidewall of the brass or steel cup assembled on a plastic or paper shotshell.
A powder and shot separator of a shallow cup design which when loaded with lips down acts to help seal powder gases and so protect the rear of the shot column.
Checkering which is cut with a tool into the surface, either by hand or machine, rather than impressed.
A choke formed by a reamer during manufacture of the barrel of a shotgun.
CUT OFF RUPTURE
A generally circumferential separation in the side wall of a cartridge case. May be complete or partial.
A process of forming the helical grooves in the bore of a rifle barrel by a cutting tool which has a hook shape. Also called Hook Rifling.
Also Known As: Hook Rifling
The rate which a succession of movements repeats itself; in an automatic firearm, it is usually expressed in shots per minute that are theoretically possible to be fired, given an unlimited supply of ammunition.
CYCLING AN ACTION
The act of chambering a cartridge, firing the cartridge, opening the action, ejecting the spent cartridge case, and loading the next cartridge if applicable.
Also Known As: Firing Cycle
The rotating part of a revolver that contains the cartridge chambers.
The relationship of the axis of the chamber in a revolver cylinder to the axis of the bore.
Also Known As: Cylinder Timing
A shotgun barrel with a uniform interior diameter forward of the forcing cone to the muzzle end of the barrel.
Also Known As: Cylinder Bore Choke
The free longitudinal movement of the cylinder in the frame.
Also Known As: Cylinder End Shake, Cylinder End-Play
In a revolver, the space between the cylinder and the barrel measured with the cylinder in the rearmost position.
Also Known As: Cylinder Gap, Barrel-Cylinder Gap, Cylinder-Barrel Gap
In revolver-type firearms, the rotational movement of the cylinder to bring the next chamber into alignment with the bore.
The pin around which the cylinder of a revolver rotates. This is a feature found on revolvers in which there is no crane. Also called Axis Pin, Base Pin, Center Pin.
Also Known As: Axis Pin, Base Pin, Center Pin
CYLINDER RELEASE LATCH
A device which permits the swinging out of the cylinder from the frame of a revolver.
Also Known As: Thumb Piece
A device to stop cylinder rotation in proper alignment with the barrel in a revolver. Sometimes called a Cylinder Latch or Cylinder Bolt.
Also Known As: Cylinder Latch, Cylinder Bolt, Bolt
CYLINDER STOP NOTCH
One of the machined grooves on the circumference of a revolver cylinder that is engaged by the cylinder stop in order to assure barrel and chamber alignment. Also called Bolt Notch.
Also Known As: Bolt Notch