The width of the light waves representing the image captured by the objective lens at the eye relief distance from the ocular lens is called the exit pupil.
How to bore sight a Rifle
Bore sighting is a crucial step in getting your rifle to shoot accurately. In this guide, we’ll show you how to use a bore sighter or naked eye and fine-tune your rifle’s zero for better accuracy.
Minute of Angle (MOA)
MOA is a measured way of adjusting a firearm’s sights elevation to compensate for bullet drop over distance due to gravity. It can also do the same laterally to compensate for windage.
Milliradian MIL or MRAD
Milliradians and Mils(NATO), like Minutes of Angle (MOA), are a way of adjusting a firearms sights for elevation and windage.
Parallax or parallax error is a phenomenon that occurs when the apparent difference in the position of an object is viewed from different lines of sight.