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.

H

HAIR TRIGGER

A slang term for a trigger requiring very low force to actuate. Sometimes used to describe the light pull of a second trigger in a double set trigger mechanism.


HALF COCK

The position of the hammer, when about half retracted and held by the sear, intended to prevent release of the hammer by a normal pull of the trigger. This can be the safety or loading position of many guns.


HALF COCK SAFETY

The position of the hammer, when about half retracted and held by the sear, intended to prevent release of the hammer by a normal pull of the trigger. This can be the safety or loading position of many guns.

Also Known As: Half Cock.


HALF STOCK

A rifle stock with a fore-end which extends approximately to the midpoint of the barrel.


HAMMER

A component part of the firing mechanism which strikes the firing pin or primer
sometimes through one or more transfer members. A firearm may have a concealed
hammer or an exposed hammer.


HAMMER BLOCK

A device intended to isolate the hammer from the firing-pin except when the trigger is pulled.


HAMMER FORGED

The process of forming the interior and/or exterior shape of the barrel of a firearm by pneumatic or hydraulic hammers. Also called Hammered Barrel; Hammered Forged Rifling, Hammer Forged.

Also Known As: Hammered Barrel, Hammered Rifling, Swaged Rifling, Barrel Swaging


HAMMER NOSE

That part of the hammer which serves as the firing-pin.


HAMMER NOTCH

One or more grooves in the outer surface of a hammer which interface with the hammer or sear.


HAMMER SPUR

The knob or extension on an exposed hammer which acts as a cocking or decocking aid.


HAMMER STRUT

A component part of some firing mechanisms which is connected between the hammer and the trigger and which acts to move the hammer to the firing position when the trigger is pulled. Also refers to a strut which guides a mainspring to power a hammer.

Also Known As: Strut


HAMMERED RIFLING

The formation of the spiral grooves in the bore of a rifle barrel by means of an internal mandrel and external hammers. Sometimes called “Hammer Forged Rifling”.

Also Known As: Swaged Rifling, Hammer Forged Barrels


HAMMERLESS

Any firearm having a concealed hammer or striker.


HAND

The lever that rotates a revolver cylinder. Sometimes called a Pawl or Dog.

Also Known As: Pawl, Dog


HAND CHECKERING

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


HAND STOP

An attachment beneath the fore-end or forearm of a target rifle to restrict the forward movement of the hand. Often also used to attached a target sling.

Also Known As: Knuckle Buster


HAND TRAP

A small, hand-operated target throwing device.


HANDGUN

A firearm designed to be held and fired with one hand.


HANDLOADING

The process of manually assembling a cartridge from component parts (casing, primer, propellant and bullet or wads and shot).


HARD SHOT

Lead Shot containing more than 0.5% alloying metal to increase its hardness. Also called Chilled Shot.

Also Known As: Chilled Shot


The end of the cartridge case in which the primer or priming is inserted and the surface upon which the headstamp identification is imprinted.


HEAD CLEARANCE

The distance between the head of a fully seated cartridge or shell and the face of the breech bolt when the action is in the closed position. Commonly confused with headspace.


HEADSPACE

The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats. 1. BELT: A type of chamber design in which the cartridge seats in the chamber on an enlarged band ahead of the extractor groove of the cartridge body. 2. MOUTH: A type of chamber design in which the cartridge seats in the chamber on the mouth of the cartridge case. 3. RIMLESS: A type of chamber design in which the cartridge seats in the chamber on the shoulder of the cartridge case. 4. RIMMED: A type of chamber design in which the cartridge seats in the chamber on the rim or flange of the cartridge case.


HEADSPACE GAUGE

A device used in a firearm to determine the distance between the breech face and the chamber surface on which the cartridge seats. Also called Breeching Plug.

Also Known As: Breeching Plug


HEADSTAMP

Numerals, letters and symbols (or combinations) stamped into the head of a cartridge case or shotshell to identify the manufacturer, caliber or Gauge, and other additional information.


HEEL

1. The part of a rifle or shotgun stock at the top of the butt end. 2. The rear portion of a bullet.


HEEL CAVITY

A recess in the base of a bullet.


HEELED BULLET

A bullet design where the portion of the bullet exterior to the shellcase has the same diameter as the case, and steps down to a narrower "heel" portion that fits inside the case.


HIGH BASE

The term commonly applied to a shotshell with a high metal cup, but properly applies to the height of the internal base wad. Often misused as synonymous with high brass or high cup.


HIGH BRASS

Common terminology referring to the length of the external metal cup on a shotshell. See High Cup


HIGH CUP

Correct term for shotshells having a high metal head type of construction.


HINGE PIN

A cylindrical member at the forward end of a frame about which the barrel or barrels pivot. Also called a Joint Pin.

Also Known As: Joint Pin


HINGED FRAME ACTION

An action in which the barrel(s), one or more being either smooth or rifled, is pivoted on the frame. When the action is open, the barrel may pivot up or down or sideways for loading or unloading. When the action is closed, the breech of the barrels swings against the standing breech. Opening is normally accomplished by movement of a top, side, or under lever. A top break action is an example of a hinged frame action.


HINGED OR FOLDING TRIGGER

A trigger which is hinged to fold forward.


HOLLOW BASE BULLET

A bullet with a deep heel cavity.


HOLLOW POINT BULLET

A bullet with a cavity in the nose to facilitate expansion.

Also Known As: Open Point Expanding Bullet

Related Terms: EXPANDING BULLET


HOODED SIGHT

A front sight that is provided with a cover to shade it from direct light.

Also Known As: Sight Cover


HOOK OF LUMP

A notch machined into a lump used to mate with the hinge pin.


HORIZONTAL DISPERSION

The greatest horizontal distance between any two bullet holes on a target, normally measured center-to-center.


HULL

A slang term for a cartridge or shotshell case.