Eye relief is a critical factor to consider when selecting a scope for your firearm. It is the distance from the eyepiece of the scope to your eye where you can still see a full, clear image. Ideally, this distance should be at least three inches, as longer distances can cause fatigue and strain on your neck and shoulder muscles. Eye relief is often measured in inches, and varies depending on the type of scope you choose. For example, fixed-power scopes typically have longer eye relief than variable-power scopes, making them more suitable for larger caliber rifles. Furthermore, eye relief also depends on the type of reticle in the scope; some reticles need more eye relief than others. It is important to know your firearm and the type of shooting you plan on doing when selecting a scope with the right eye relief. By ensuring that you have adequate eye relief, you will be able to make accurate shots with ease and comfort.