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.
I
IGNITION TIME
The elapsed time from moment of firing pin contact on the primer to the point on the X (time) axis equal to the point where the pressure time curve indicates propellant burning has initiated.
IMPRESSED CHECKERING
A heated die process which produces a carved effect in the gun stock or forearm.
IMR POWDER
The abbreviation for Improved Military Rifle Powder. A single base, tubular, smokeless propellant.
IN BATTERY
A firearm is said to be “In Battery” when the breeching mechanism is in the proper position for firing.
IN LINE
A firearm design incorporating it’s firing mechanism substantially in line with the longitudinal axis of the barrel. Ignition gases are typically induced concentric to the bore with this design.
INDUSTRIAL CARTRIDGE
1. Usually a blank cartridge used in industrial applications such as stud drivers. Usually color coded to indicate power level. Also referred to as power tool cartridges and power actuated tool cartridges. 2. 8 Gauge industrial loads with single projectiles or buckshot used for cleaning continuous cement kilns and other industrial applications.
Related Terms: POWDER ACTUATED TOOL, POWER DEVICE CARTRIDGE
INERTIA BLOCK
1. A device intended to function during recoil to set the fire control mechanism to fire a second barrel. 2. A device intended to function during recoil to prevent doubling on some double barrel shotguns.
INERTIA BULLET PULLER
A tool using impact to remove a bullet from a cartridge case.
INERTIA FIRING PIN
A design in which the striker or hammer stops after hitting the firing pin, requiring the firing pin reach the primer under its own inertia.
INERTIA OPERATED ACTION
A self-loading type firearm in which components of the locking system remains relatively stationary while the rest of the firearm recoils and thereafter unlocks the breech bolt to complete the cycle of extracting, ejecting and reloading.
Also Known As: Inertia Operated
INERTIA TRIGGER
The term used for firearms having two barrels and a single trigger wherein the inertia resulting from the recoil forces of firing one barrel causes the trigger sear to switch to the unfired barrel. A second pull of the trigger can then fire the second barrel.
INSIDE LUBRICATED BULLET
A bullet having lubrication in grooves on the bearing surface of the projectile. When seated, these grooves are covered by the cartridge case.
INSTRUMENTAL VELOCITY
The velocity of a projectile, or a shot charge, that is recorded by suitable instrumentation located a predetermined distance from the muzzle of a test barrel or a firearm.
INTEGRALLY-SUPPRESSED BARREL
An assembly which includes a barrel and suppressor elements, such as baffles or vents, incorporated onto the barrel by design.
Related Terms: SUPPRESSOR
INTERCHANGEABLE BARREL
Barrels which may be installed on a particular action without factory fitting.
INTERIOR BALLISTICS
The science of ballistics focusing on all thermochemical and physical events from primer ignition through projectile exit from the muzzle.
IRON FORE-END
On firearms with a one-piece stock, an intermediate part that holds the wood against the barrel and frame and retains the latch mechanism.
IRON SIGHT
Any sight, front or rear, not containing optical magnifying elements. It may be fixed or adjustable. Also called Metallic Sight.
Also Known As: Metallic Sight