What is parallax on rifle scope? Parallax is an important optical concept that can affect your shooting accuracy when using a rifle scope. Simply put, parallax is the apparent shift of the reticle (crosshairs) in relation to the target when you move your eye position behind the scope.

How Does Parallax Occur?

Inside a rifle scope, the reticle is positioned at a certain focal plane. If the target image and the reticle are not on the same focal plane, moving your eye slightly off-center will make the reticle appear to move against the target. This effect is called parallax error.

Why Does Parallax Matter?

If you don’t correct for parallax, your point of aim may shift when you move your head, leading to less accurate shots. This is especially important for long-range shooting where even small misalignments can cause significant bullet impact deviation.

How to Adjust for Parallax

Many rifle scopes come with a parallax adjustment feature—usually a side focus knob or adjustable objective lens—that lets you focus the target and reticle on the same plane. Properly adjusting parallax removes the reticle’s movement relative to the target, ensuring your shots stay consistent regardless of eye position.

When Is Parallax Most Noticeable?

• At longer shooting distances (beyond 100 yards/meters)

• With high-magnification scopes

• When using scopes without fixed parallax settings

Summary

Parallax on a rifle scope is the optical illusion of the reticle moving relative to the target when your eye moves. Correcting parallax through scope adjustment improves shooting accuracy and consistency, especially at longer distances. Understanding and managing parallax is essential for any serious shooter.