Glossary

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.

P

PALM REST

An adjustable support for a target rifle extending downward from the forearm.


PAPER DISC

Small circular piece of treated paper cut and pressed into the primer cup in contact with the priming mixture. Also called Foil.

Also Known As: Foil


PAPER SHELL

Shotshells which are constructed with a body made from paper tubing.

Also Known As: Paper Shotshell


PARKERIZING

A non-reflecting, rust-resistant finish used on metal surfaces of some firearms. Also called Phosphatizing or Phosphate Coating.


PARTITION BULLET

A bullet designed for controlled expansion having a jacket which is divided into two cavities which enclose the forward and rear cores of the bullet. It is designed so the first cavity expands and the rear cavity holds together for penetration.


PATCH

1. A piece of cloth used with a rod to clean the bore of a firearm.
2. A piece of paper wrapped around lead bullets to prevent leading of the barrel and to improve the gas seal.
3. In muzzleloading firearms, the piece of cloth surrounding the bullet or ball to improve the gas seal.


PATCHED BALL

1. For modern cased ammunition, the term patched ball refers to a full metal jacketed bullet (FMJ). 2. For muzzleloading, the term refers to round or conical lead projectiles that utilize cloth or other material which acts as a gas seal or a guide for the projectile. 3. Early fixed ammunition using paper as a gas seal for the projectile.


PATRIDGE SIGHT

A rear sight on pistols or revolvers having a flat top with a square notch used with a broad flat-topped front sight. Named after E. E. Patridge.


PATTERN

The distribution of individual pellets fired from a single shotshell in a shotgun. Generally measured as a percentage of the total number of pellets striking within a 30” circle at 40 yards. Some skeet guns are measured using a 30” circle at 25 yards.


PEAK PRESSURE

That maximum instantaneous pressure measured in the chamber of a firearm, produced by the expanding propellant combustion gases.


PEEP SIGHT

Common, popular term for aperture rear sights.

Also Known As: Receiver Sight


PELLET (PROJECTILE)

1. A common name for the small spherical projectiles loaded in shotshells.
2. A non-spherical projectile used in some air rifles.


PENETRATION

Travel of a bullet or shot pellet into the target medium.


PERCUSSION

A means of ignition of a propellant charge by a mechanical blow against the primer (modern) or cap (antique).


PERCUSSION CAP

A small, generally cylindrical, metallic cup containing primer mix used to ignite the main powder charge in some muzzle-loading firearm designs.


PERCUSSION COMPOSITION

A combination of explosive and/or pyrotechnic-type ingredients, which, when pressed into a percussion cap, will ignite upon sufficient impact from a hammer or striker and, in turn, initiate the propellant in a muzzle loader.


PIERCED PRIMER

A fired primer which has been perforated by the firing-pin.

Also Known As: Punctured Primer


PIEZOELECTRIC PRESSURE TRANSDUCER

A device which generates an electrical charge that is proportional to the pressure applied to its crystal element.

Also Known As: Pressure Transducer


PISTOL

A firearm intended to be fired with one hand in which the chamber(s) are integral to the barrel(s).


PISTOL GRIP

On shoulder firearms, that part of the stock behind the trigger, shaped similar to the grip of a pistol to afford a better grasp.


PISTOL GRIP ADAPTER

An accessory made to attach to the front of a revolver grip to afford a better grasp.


PISTOL GRIP STOCK

A stock or buttstock having a downward extension behind the trigger guard somewhat resembling the grip of a pistol.


PISTON RING

A sharp edged ring mounted on the piston of gas operated automatic and semiautomatic firearms which makes a close seal between the piston and cylinder wall, and by a scraping action reduces the accumulation of carbon in the cylinder.


PIT

A scar on a metal surface usually the result of extensive rusting.


PITCH

1. (Rifling) the distance a bullet must travel in the bore to make one revolution. 2. (Grips) the angle that the front of the handgun grip makes with the line of sight. 3. A component used in making clay targets. 4. See Stock Dimensions.


PIVOTING BLOCK ACTION

An action in which the breech block pivots in an arc to expose or lock the breech.


PLASTIC SHOTSHELL

A complete round of ammunition having a plastic body, a basewad that may or may not be a single unit and a metallic head.


PLATED BULLET

The entire bullet, or just the jacket, electrolytically plated with a different material.


PLATED SHOT

Copper or nickel-plated shot, coated to increase apparent shot hardness and reduce in-bore shot deformation.

Also Known As: Coated Shot


PLINKING

The informal target shooting at inanimate objects other than paper targets located at arbitrary or indefinite distances from the firing point.


PLUG BULLET

1. A device used in scoring bullet holes in a paper target. 2. A pin inserted in a bullet mold to form a cavity in the nose or base of a bullet.


PLUG SCREW

Screw used to fill holes for sight or telescopic sight mounting when not in use. Also used to fill access holes to internal pins. Also called Dummy Screw.

Also Known As: Dummy Screw


POINT OF IMPACT

The point at which a bullet hits a target.


POINT-BLANK-RANGE

Very close range.


POINTED PROJECTILE

A projectile that is designed with a pointed profile.


POINT-OF-AIM

The exact point on which the shooter aligns the firearm’s sights.


POST SIGHT

A front sight with flat sides and top.


POWDER

Commonly used term for the propellant in a cartridge or shotshell.


POWDER ACTUATED TOOL

A class of tools, such as nail drivers, that use the expansion of propellant combustion gases as their motive force.

Also Known As: PAT


POWDER BURN

A burn that may result from contact with hot powder particles or propellant combustion gases.


POWDER BURNING RATE

The speed with which a propellant burns inside a cartridge case. It is affected by both physical and chemical characteristics, as well as conditions under which the powder is burned.

Also Known As: Burning Rate, Burning Speed


POWDER CHARGE

The amount of powder by weight in a cartridge case or shotshell.


POWDER DETERIORATION

1. (Smokeless Propellant) The degradation of propellant from the decomposition of the explosive components of the propellant. This can be accelerated by improper storage conditions.
2. (Black Powder) The degradation of black powder typically caused by absorption of moisture from the air.


POWDER FOULING

Residue left in firearms after firing, either from unburned propellant or its solid combustion products.


POWDER MEASURE

A device to measure quantities of powder volumetrically.


POWDER MILL

1. The machinery that produces Black Powder to the required geometry. 2. A manufacturing facility that produces powder, classically applied to Black Powder facilities but can be used for Smokeless Propellant manufacturing plants.


POWDER SCALE

A balance or weighing instrument for accurately weighing powder charges.


POWER DEVICE CARTRIDGE

Cartridges designed to accomplish mechanical actions. The cartridges consist of a shellcase and propellant that when ignited produces gases for inflation, linear or rotary motion, activate diaphragms, or project fastening devices. See also, Industrial Cartridge.

Related Terms: INDUSTRIAL CARTRIDGE


PREMATURE FIRING

The improper firing of a cartridge or shotshell before the breech or action of the firearm is fully closed and locked into firing position.


PRESCRIBED LOAD

For every caliber of metallic cartridge and the numerous bullet weights used in each, and for each shotshell gauge or bore, and the various shot weights loaded in each, a particular combination of components should be used. Collectively, the correct components for any given cartridge or shell may be referred to as the prescribed load.


PRESSURE

In a gun or cartridge, the force imparted to various components that is developed by the expanding gases generated by the deflagration of the propellant when fired.


PRESSURE BARREL

A barrel, typically heavy-walled, made in accordance with a standards-setting organization specifications, with appropriate features for the installation of instrumentation to measure pressure.


PRESSURE CURVE

A graph of the relationship of chamber pressure to time or travel in a firearm when a cartridge or shell is fired.


PRESSURE DETERMINATION

The act of measuring the pressure generated in cartridges or shotshells contained in the chamber of a test barrel. See Pressure. See Average Pressure. See Pressure Barrel. See Chamber Pressure. See Pressure Curve.


PRESSURE ESTIMATION

Attempting to roughly establish pressure of a cartridge by visual observation or measurement of a fired cartridge case.


PRESSURE GAUGE

A piston and crusher system, or a piezoelectric transducer system used to measure internal barrel pressure in a firearm or test device.

Also Known As: Piezo Transducer, Copper Crusher


PRETRAVEL

The initial distance the trigger moves prior to sear movement. Also known as Trigger Take-up or Slack. See Trigger Creep.

Also Known As: Trigger-Take Up, Trigger Slack


PRIMER

An ignition component containing explosive mixture in a metallic cup, which provides a source of heat and flame when initiated.  Percussion primers utilize mechanical impact for initiation energy and may have an anvil in the cup or the anvil may be integral to the cartridge case. (See Boxer Primer and Berdan Primer.)  To a lesser extent, electrically-initiated primers have been used in sporting small arms ammunition and are currently used in some military small arms applications.


PRIMER CRATERING

A circumferential rearward flow of metal surrounding the indentation of a firing-pin in a fired primer cup.

Also Known As: Primer Flow-Back


PRIMER CUP

Brass or copper cup designed to contain priming mixture.


PRIMER FLASH

The illumination produced by the extremely hot gases which result from the very rapid build-up of pressure and temperature when the priming mixture detonates.


PRIMER LEAK

The escape of gas between the primer cup and head of the cartridge case, or shotshell head.


PRIMER PELLET

The explosive component of a primer.


PRIMER POCKET

A cylindrical cavity formed in the head of a metallic centerfire cartridge case, or in the head of a shotshell, to receive an appropriate primer or battery cup primer assembly.


PRIMER SEATING

The insertion of a centerfire primer or battery cup in the head of a cartridge case or shotshell. Properly seated, it should be flush or below the face of the head.


PRIMER SETBACK

The condition when a primer, or battery cup primer assembly, moves partially out of its proper location in the primer pocket of a metallic cartridge or shotshell during firing.


PRIMER TUBE

A tube for holding primers in a handloading press.


PRIMING MIX/MIXTURE

A combination of explosive and/or pyrotechnic-type ingredients, which, when pressed into a cup or spun into the rim cavity of a rimfire shell, will ignite upon sufficient impact from a firing-pin and, in turn, initiate the propellant in a cartridge or shotshell.


PROGRESSIVE BURNING POWDER

A smokeless propellant in which the burning rate is controlled by physical and/or chemical means.


PROJECTILE

An object propelled from a firearm by the force of rapidly burning gases or other means.


PROJECTILE ENERGY

The kinetic energy of a projectile.


PROJECTILE ROTATION

The spinning motion that is imparted to a projectile due to engagement with the rifling in the barrel of a firearm, as it is driven down the barrel. The rate of rotation is dependent upon the rate of twist of the rifling and the velocity. The barrel twist (left or right) determines the direction of the rotation.


PROOF MARK

A stamp applied at or near the breech or other stressed component of a firearm after it has passed a proof test.


PROOF TEST

The test of an assembled firearm or individual components by firing a Definitive Proof Cartridge. See Definitive Proof Cartridge.

Related Terms: DEFINITIVE PROOF CARTRIDGE


PROPELLANT

In a firearm, the chemical composition which, when ignited by a primer, generates gas. The gas propels the projectile. Also called powder, gunpowder, smokeless powder, blackpowder.

Also Known As: Powder, Gunpowder, Smokeless Powder, Blackpowder


PROVISIONAL PROOF CARTRIDGE (HISTORICAL)

A cartridge loaded to specified pressures higher than service loads to test barrels during manufacture, but before assembly.


PULL-THROUGH

A flexible device that is pulled through the barrel of a firearm to clean the barrel.


PUMP ACTION

An action in which a moveable fore-end is manually actuated in a motion generally parallel to the barrel. This motion is transmitted to a breech bolt assembly which performs all the functions for loading and extracting cartridges. This type of action is prevalent in shotguns and is found to a lesser extent in rifles.

Also Known As: Slide Action, Trombone Action, Pump Gun


PUSH BUTTON SAFETY

A type of manual firearm safety operated by a lateral force on a button usually located in the trigger guard. Also called Cross Bolt Safety.

Also Known As: Cross Bolt Safety


PYRAMID SIGHT

A type of front sight of triangular appearance. Also called Barleycorn Sight.

Also Known As: Barleycorn Sight