Letter: P

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

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.

A burn that may result from contact with hot powder particles or propellant combustion gases.

Residue left in firearms after firing, either from unburned propellant or its solid combustion products.

1. (Smokeless Propellant) The degradation of propellant from the decomposition of the explosive components of the propellant. This can be accelerated by improper storage conditions.
2. (Black Powder) The degradation of black powder typically caused by absorption of moisture from the air.

The amount of powder by weight in a cartridge case or shotshell.

The speed with which a propellant burns inside a cartridge case. It is affected by both physical and chemical characteristics, as well as conditions under which the powder is burned.