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.

T

TACTICAL SHOTGUN

A shotgun with a short barrel designed for tactical applications.


TAKE DOWN

To disassemble a firearm for cleaning, repair or transportation.

Also Known As: Stripping


TAKEDOWN

A type of firearm designed for ease of disassembly and transportation.


TANG

A rearward projecting tongue on a receiver or frame to which the buttstock is attached. Some parts of the operating mechanism of a firearm may also pass through the tang. A gun may have either or both an upper and lower tang.


TANG SAFETY

A type of safety in which the external control component is mounted on the upper receiver tang of a firearm.

Also Known As: Sliding Safety


TANG SCREW

The screw or screws passing through either one or both tangs by which the stock or trigger guard is attached to the receiver or frame.


TANG SIGHT

Any sight mounted on the upper tang of a firearm.


TANGENT OGIVE

A projectile nose with the curvature tangent to the cylindrical bearing portion.


TANGENT SIGHT

A rear sight in which the blade is adjusted for elevation correction by sliding along a curved cam or cams.


TAPER CRIMP

A method of securing a bullet by lightly swaging the metallic casemouth into the bullet body.

Also Known As: Taper Crimp


TARAGE TABLE

A tabulation of values relating to the compressed length of a crusher cylinder to the chamber pressure.


TARGET HAMMER

A firearm hammer having a wider spur designed for convenient and rapid cocking.


TARGET RIFLE

Any rifle designed and equipped for match or target shooting.


TARGET SHOOTING

The act of shooting at inanimate objects. “formal” target shooting is done at specified distances at targets designated for scoring. “Informal” target shooting is done at varying distances at impromptu targets for practice. See Plinking.

Related Terms: PLINKING


TARGET SIGHT

Sights designed for use in competitive shooting.


TARGET SLING

A special form of strap designed to aid in support of the firearm in target shooting.


TARGET STOCK

Any stock specifically made for firearms designed for target shooting.


TARGET TRIGGER

1. A trigger mechanism which provides for adjustment of such characteristics as pull force, travel or overtravel. 2. A trigger which provides a large bearing surface for the trigger finger. 3. A relatively light, crisp trigger designed to assist in accurate shooting.


TARGET(ING)

The act of shooting a firearm to align sights. See Sighting In.

Also Known As: Sighting In

Related Terms: SIGHTING-IN


T-BOLT

A patented reciprocation and locking system for use on a rimfire rifle. Sometimes used to describe straight-pull bolt action rifles with a horizontally protruding straight bolt handle.


TELESCOPE MOUNT

A device to hold a telescope on a firearm.


TELESCOPIC SIGHT

A sight containing optical elements which magnifies the target.

Also Known As: Scope, Riflescope, Telescope


TEMPERATURE OF IGNITION

The lowest temperature to which the surface of material must be raised for the combustion of the material to become self-sustaining.


TENON

1. On firearms, it is the projecting part of wood components which fit into the receiver or frame. 2. On ammunition, that portion of the rimfire bullet which fits into the cartridge case, from bullet base to bottom of band. Also called Heel. See Heel.

Also Known As: Heel

Related Terms: HEEL


TERMINAL BALLISTICS

The branch of ballistics related to the effects of projectiles at or inside the target.


TERMINAL ENERGY

The remaining energy of a projectile at the point of impact.

Also Known As: Striking Energy


TERMINAL VELOCITY

The remaining velocity of a projectile at the point of impact. See Striking Velocity.

Related Terms: STRIKING VELOCITY


TEST BARREL

A barrel of special dimensions used for testing ammunition.


THREE-QUARTER STOCK

A rifle stock which has an abnormally long fore-end, but which does not reach the muzzle.


THROAT

The tapered portion of the bore of a barrel, immediately ahead of the chamber which is sized to provide clearance for the bullet of the loaded cartridge. Also referred to as Leade or Ball Seat and is associated with Free Bore. See Free Bore.

Also Known As: Leade, Ball Seat

Related Terms: FREE BORE


THUMB PIECE (CYLINDER RELEASE)

A latch used on some revolvers to release the cylinder. Sometimes called a “Thumb Latch”.

Also Known As: Thumb Latch


THUMB REST

A ledge in the grip area of a rifle or handgun on which to rest the thumb of the trigger hand.


THUMB SAFETY

A type of manual safety in which the external control component is located for convenient operation by the thumb of the trigger hand.


THUMBHOLE STOCK

Any stock having a contoured hole in the grip area to accommodate the thumb of the trigger hand.


TIME OF FLIGHT

The total elapsed time that a projectile requires to travel a specific distance from the muzzle.


TOE

The bottom (lower) end of a buttplate and adjacent portion of the stock on a shoulder firearm.


TONG TOOL

An unmounted, portable handloading tool using a plier action for handloading centerfire cartridges. Also called Nutcracker Tool.

Also Known As: Nutcracker Tool


TOP EXTENSION

A projection which extends behind the breech end of the barrels on some breakopen firearms. When the gun is closed, it fits into a corresponding recess slot in the frame and is used for locking purposes.


TOP STRAP

That portion of a revolver frame which passes over the cylinder.

Also Known As: Strap


TOP WAD

The closure disc over the top of the shot column held in place by a rolled crimp.


TOP-BREAK ACTION

An action in which the barrel or barrels are connected to the frame by a pivot point. Upon release of the locking mechanism, usually by a top, side or under-lever, the barrel or barrels rotate around the pivot point away from the standing breech.

Also Known As: Top-Break, Break-Open Action, Tip-Up,

Related Terms: STANDING BREECH


TRAJECTORY

The curved path of a projectile from muzzle to target.

Also Known As: Ballistic Curve


TRAJECTORY TABLE

A computed table describing the downrange trajectory of a projectile or of shotshell pellets, buckshot or rifled slugs.


TRAP

A clay target throwing device.


TRAP DOOR ACTION

An action in which a top-hinged breech block pivots up and forward to open. Locking on this action is accomplished by a cam piece located at the rear of the breech block that fits into a mating recess. Also known as a “Cam Lock.”

Also Known As: Cam Lock


TRAP GUN

A shotgun specifically designed for the game of Trap shooting.


TRAP SHOOTING

A shotgun target sport in which clay targets are thrown away from the shooters by a reciprocating trap located forward of the firing line.


TRAP-DOOR BUTTPLATE

A type of buttplate with a hinged closure plate in the butt-end of a firearm. Opening of the trap door exposes a recess in the stock which can be used for storage.


TRIGGER

That part of a firearm mechanism which is moved manually to cause the firearm to
discharge.


TRIGGER BAR

A connecting piece between the trigger and the sear.


TRIGGER CREEP

The sensible movement of the trigger or take-up or pretravel, prior to sear release.

Also Known As: Creep


TRIGGER GUARD

A rigid loop which partially surrounds the trigger to reduce the possibility of accidental discharge.


TRIGGER LOCK

1. An accessory for blocking unauthorized trigger movement during gun storage. Must never be applied to a loaded firearm. 2. A form of firearm safety blocking trigger movement.


TRIGGER MECHANISM

Those parts which, when pressure is applied to the trigger, release the hammer or striker. Also called Fire Control.

Also Known As: Fire Control


TRIGGER PLATE (ASSEMBLY)

1. A metal plate fitted to the lower part of some frames through which the trigger or triggers pass. 2. A component attached to the frame or receiver of some firearms, which supports the major components of the firing mechanism and may have the trigger guard as an integral portion.


TRIGGER PULL (FORCE)

The average force which must be applied to the trigger of a firearm to cause the sear, striker, or hammer to release with the force applied approximately parallel to the bore line.


TRIGGER PULL SCALE

A device for measuring trigger release force.


TRIGGER SHOE

An accessory which is attached to the trigger to give a much larger trigger-finger bearing surface.


TRIGGER SQUEEZE

A gradual increase of pressure on a trigger until it releases.


TRIGGER STOP

1. A device to prevent certain firearms from being fired until the finger lever is closed. 2. A device to prevent over-travel of the trigger.


TRIP

A part of the mechanism of some firearms which is released by the action of the trigger.


TRIPLE BASE POWDER

A propellant composed of colloided nitrocellulose, nitroglycerine and nitroguanidine. Generally used in large caliber military ammunition.


TRUNCATED BULLET

A design of a flat-nosed bullet having a conical shape rather than a nose formed by a radius.

Also Known As: Truncated Projectile


TRUNCATED CONE BULLET

A design of a flat-nosed bullet having a conical shape rather than ogive formed by a curve or radius.


TRY-GUN

A shoulder firearm having a stock which is fully adjustable for length of pull; drop at comb, Monte Carlo and heel; pitch and cast. It is used for fitting of custom made firearms to a specific shooter’s physical characteristics.


TUBE

1. The cylindrical body of a shotshell. 2. Improper term for a shotgun barrel. 3. A barrel insert to allow firing of a smaller gauge shotshell.


TUBE CUTOFF

A circumferential separation of a shotshell tube or body.


TUBE SIGHT

A metal tube that contains the rear sight.


TUBULAR MAGAZINE

A metal tube that contains cartridges or shells end to end.


TUMBLER

An English term that is sometimes used to denote a shotgun hammer. Also refers to an interior part of gun locks which contain notches that interact with the sear.


TUMBLING

1. The end-over-end rotation of an unstable projectile in flight. 2. A cleaning and polishing process, sometimes used in firearm part and ammunition manufacturing.


TUNNEL MOUNT

A telescope mount arrangement which has a hollowed-out base through which the iron sights may be seen and used.


TURNBOLT ACTION

A bolt action firearm on which it is necessary to rotate the bolt handle upwards for unlocking before it can be pulled to the rear. Similarly, it is necessary to rotate the bolt handle downward after closing to lock the firearm and enable the gun to be fired.

Also Known As: Turn-Bolt


TWIN-SINGLE TRIGGER

A double trigger arrangement used on some double-barrel firearms, wherein one or both triggers will, with each pull, fire the barrels sequentially. They are non-selective.


TWIST

The distance required for one complete turn of rifling usually expressed as a ratio, e.g., 1 in 10 inches.


TWO PIECE STOCK

A stock consisting of two separate parts, the buttstock and forearm.


TWO-PIECE MOUNT

A telescope mount having two separate base band ring assemblies.