(1) A hole(s) pierced or drilled through the web in the primer pocket of a metallic cartridge case. May also be known as a Gas Vent or Gas Port.
(2) The hole in the end of a battery cup primer used in shotshells. May also be known as a Gas Vent or Gas Port.
(3) The hole in a percussion nipple. May also be known as a Gas Vent or Gas Port.
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