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.

M

MACHINE CHECKERING

A process of wood carving gun stocks by machine rather than by hand.


MACHINE GUN

A fully automatic firearm that loads and fires live cartridges and ejects the spent cartridges continuously when the fire mechanism is held until ammunition is exhausted, the firearm's designed burst cycle is completed or the firing mechanism is released.

Also Known As: Full Automatic


MACHINE REST

Mechanical apparatus used for holding a firearm in a precisely controlled, selected position for testing the accuracy of the ammunition or the firearm.


MAGAZINE

1. A building for the storage of either ammunition or its components. 2. A receptacle for a firearm that holds a plurality of cartridges or shells under spring pressure preparatory for feeding into the chamber. Magazines take many forms, such as box, drum, rotary, tubular, etc. and may be fixed or removable.


MAGAZINE CATCH

The device that retains or releases the magazine in a firearm. Also known as Magazine Latch or Magazine Release.

Also Known As: Magazine Latch, Magazine Release, Magazine Lock


MAGAZINE CUT OFF

A mechanical device that enables the user to selectively enable or disable the magazine feed mechanism of a firearm.

Also Known As: Cut Off


MAGAZINE FED

A repeating firearm in which the ammunition for subsequent firing is fed from a magazine.


MAGAZINE FOLLOWER

A spring-actuated device to move cartridges in a magazine into the feeding position.


MAGAZINE PLUG

1. A part inserted in a magazine to reduce its capacity. 2. A part in the end of a tubular magazine which closes the end and retains the spring.


MAGAZINE SPRING

The spring in a magazine that exerts its thrust against the follower.


MAGNUM

A non-technical term commonly used to imply higher performance than standard cartridges or shells of a given caliber, or gauge or similar cartridges. Rifles, handguns or shotguns that are designed to fire Magnum cartridges or shells may also be described with the term Magnum.

Also Known As: Magnum Cartridge


MAINSPRING

The mechanical, energy storage device that operates the striker or hammer of a firearm.


MALFUNCTION

Failure of a firearm to perform properly due either to the firearm or the ammunition.


MANNLICHER MAGAZINE

A type of rotary magazine.


MANNLICHER STOCK

A full length rifle stock which extends from the butt to the muzzle.


MANUAL SAFETY

A safety device on some firearms that must be manually engaged and subsequently disengaged to permit normal firing.


MARK

A term used in conjunction with a number to designate a specific model or type of firearm or ammunition.

Also Known As: M, Mk


MARKINGS

Words or symbols, stamped, rolled, cast or engraved, on a firearm designating the manufacturer, model, origin, caliber or gauge, choke, material, etc.


MATCH AMMUNITION

Ammunition made specifically for match target shooting. Produced with special controls to assure maximum uniformity of cartridge performance.


MATTE

A dull non-reflecting metallic surface.

Also Known As: Matte Finish


MAXI BALL

An elongated, heavy weight bullet, usually incorporating annular exterior grooves to hold lubricant.. Designed to be loaded and fired without a patch, it’s major diameter being slightly larger than bore diameter causing engraving by the rifling upon loading.


MAXIMUM CHARGE

The greatest charge weight, in grains, of a particular propellant that may be used with other specified ammunition components without exceeding the safe, maximum, allowable pressure limit for the specific cartridge or shell being loaded.


MAXIMUM RANGE

The greatest distance a projectile can travel when fired at the optimum angle of elevation of the gun barrel.


MEAN RADIUS

The arithmetic mean of the distances between the centers of each shot hole from the calculated group center.


MECHANICAL TRAP

A mechanically operated clay target throwing device.


MEPLAT

A term for the blunt tip of a bullet, specifically the tip’s diameter.


METAL FOULING

Metallic bullet material left in the bore after firing.


METALLIC AMMUNITION

A generic term for rimfire and centerfire ammunition derived from their metallic cases.


METALLIC CARTRIDGE

Ammunition having a metallic cartridge case.


METFORD RIFLING SYSTEM

A form of rifling with shallow grooves that are arcs of less than half of the groove diameter.


MICROMETER POWDER MEASURE

An adjustable, volumetric device for measuring propellant powders.


MICROMETER SIGHT

A sight with a mechanism for adjusting windage and elevation settings controlled by cylindrically calibrated knobs, usually with detents to control and indicate setting intervals.


MIDDLE SIGHT

A second, smaller bead sight near the middle of the barrel or barrels of some shotguns.

Also Known As: Mid Bead Sight


MID-RANGE

1. A term that defines a specific point in the trajectory of a projectile that is half the distance between the firearm and the target. 2. A reduced velocity, centerfire cartridge, used principally in target shooting.


MID-RANGE TRAJECTORY

The distance, measured in inches, that a projectile travels above the line of sight at a specific point in the trajectory that is half the distance between the firearm and a target.


MIL

The angle subtended by one unit at 1000 units.


MINIE BALL

A conical nosed lead bullet, slightly under bore diameter, incorporating a hollow base, designed to expand into the rifled bore upon firing for gas sealing purposes without the use of a patch.


MINUTE OF ANGLE (M.O.A.)

An angular measurement method used to describe accuracy capability. A minute of angle is one sixtieth of a degree, and subtends 1.047 inches at 100 yards, which for practical shooting purposes is considered to be one inch. A minute of angle group, therefore, equals one inch at 100 yards, two inches at 200 yards, etc.


MIRAGE

A visual phenomenon that appears to displace a target from its true position through a shimmering effect. It is caused by heated air that deflects light rays.


MISFEED

Any malfunction during the feed cycle of a repeating firearm resulting in the failure of a cartridge or shell to enter the chamber completely. Also known as Failure to Feed.

Also Known As: Failure to Feed


MISFIRE

A failure of the priming mixture to be initiated after the primer has been struck an adequate blow by a firing-pin or the failure of the initiated primer to ignite the powder.


MONOBLOC

The solid section at the breech end of some multi-barrel guns into which the barrels are inserted.


MONTE CARLO STOCK

A stock with a raised comb to bring the eye in alignment with the sight.

Also Known As: Monte Carlo


MOUTH

The open end of a cartridge case or shotshell, from which the projectile or shot charge is expelled in firing.


MULLERING TOOL

A type of checkering tool.


MULTIPLE LEAF SIGHT

A type of open, rear sight having more than one folding leaves. It may also have one fixed leaf.

Also Known As: Three Leaf Sight


MUSHROOM

A descriptive term for the post-impact profile of a bullet that is designed to expand upon striking a target.


MUSHROOM BULLET

A bullet that has expanded upon impact into a mushroom-like shape.


MUSHROOMING

The act of expansion of a bullet upon impact with a target.


MUSKET

Military firearm with long barrel and fore-end or forearm extending nearly to muzzle.


MUSKET CAP

The ignition source for most military muzzle loading rifles of the Civil War era, usually consisting of a copper alloy cup containing the priming mix. They are larger than percussion caps and typically incorporate a continuous or segmented flanges (Wings) at the cup mouth for ease of handling.


MUZZLE

The end of a gun barrel from which the bullet or shot emerges.


MUZZLE BLAST

The resultant noise that occurs at the muzzle of a firearm when the projectile leaves the muzzle and hot gases are released.


MUZZLE BRAKE

A muzzle attachment or feature that uses the propellant combustion gas with the desired effect of redirecting the recoil.


MUZZLE CAP

A cover put on the muzzle end of a barrel to keep out foreign matter.


MUZZLE ENERGY

A projectile’s energy at the time it leaves the muzzle of a gun.


MUZZLE FLASH

The illumination which is the result of the expanding gases from the burning propellant particles emerging from the barrel behind the projectile and uniting with oxygen in the air.


MUZZLE GUARD

A device put on the end of a barrel with a hole concentric with the bore to admit a cleaning rod and keep the rod from wearing the rifling in this critical area. Not used on guns cleaned from the breech end.


MUZZLE JUMP

The generally upward motion of the muzzle of a firearm which occurs upon firing.


MUZZLE VELOCITY

The velocity of a projectile as it exits the muzzle of a firearm.


MUZZLE WAVE

The air that is compressed and moves out radially from the muzzle of a firearm after firing a projectile.


MUZZLE–BREAK

An electrical or optical device which signals the passage of shot or a projectile at the muzzle of a firearm.


MUZZLELOADER

Firearm which can only be loaded with powder and projectile(s) through the muzzle or front end of a cylinder in the case of a muzzleloading revolver.