Archives: Glossary

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

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

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

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.

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

Brass or copper cup designed to contain priming mixture.

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.

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

The explosive component of a primer.

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.