parkerizing: A method of protecting a steel surface from corrosion and increasing its resistance to wear through the application of an electrochemical phosphate conversion coating. Also called phosphating and phosphatizing.
Picatinny rail: a bracket used on some firearms to provide a standardized mounting platform.
plinking: Informal target shooting done at non-traditional targets such as tin cans, glass bottles, and balloons filled with water.
POA: point of aim.
POI: point of impact.
pump-action: A rifle or shotgun in which the handgrip can be pumped back and forth to eject a spent round of ammunition and to chamber a fresh one. It is much faster than a bolt-action and somewhat faster than a lever-action, as it does not require that the shooter remove their trigger hand during reloading. In rifles, this action is also commonly called a slide action.