• Ejector

    Mechanism that expels cartridges from a firearm More

  • Exit Pupil

    A significant characteristic of an optical viewing instrument is the diameter of the exit pupil. The exit pupil is the circular patch of image-forming light the instrument presents to your eye. If you point a riflescope toward a brightly lighted wall or a patch of clear sky (but not at the sun!) and position your eye about 10 inches from the eyepiece, along the optical axis, you will see a bright disc of light in the center of the field. That disc is the exit pupil. More

  • Expansion Ratio

    Ratio of the chamber volume to the bore plus chamber volume. To calculate, compare the chamber volume to the base of the bullet to the total volume of the chamber and the bore to the muzzle. More

  • Expansion Ratio

    The sum of the volume of the bore and powder chamber divided by the volume of the powder chamber. More

  • Extractor

    A mechanism that withdraws the fired case from the chamber of a firearm More

  • Eye Relief

    The term "eye relief" commonly refers to the distance between your eye and the eyepiece lens of an optical instrument when your eye is positioned so that you can see the entire field of view. In recreational shooting, the optical device is most likely a scope, spotting scope, binocular, or rangefinder.

    A serious pitfall with eye relief stems from taking the conventional definition too literally. For shooters, eye relief should really be redefined as the distance between your eyeglass lens and the rearmost projection of the eyepiece when you can see the entire field of view. More