Letter: O

A small hole or vent such as the gas port in the barrel of a gas-operated firearm.

A rough textured finish similar to the skin of an orange, generally referring to certain stock finishes.

A sight containing optical elements which may magnify the target.

On lever action firearms that part operated by the hand to open and close the breech.

A rear sight having a notch through which the front sight is aligned for aiming.

A type of bullet having a cavity in the tip or nose.

The momentary expansion of a cartridge case against chamber walls which minimizes the rearward flow of gases between the case and the chamber wall when the cartridge is fired.

An action in which the breech bolt is held open until the trigger is pulled.

A full length stock made from a single piece of wood. Includes both the butt and fore-end.

1. A shotshell component having the body and basewad as a single unit with a metallic cup. Sometimes called Unibody Shell. 2. A complete round of ammunition having the body and basewad as a single unit without a head of a different material.