Parallax refers to an aiming error that occurs when the shooter does not look straight through the scope but rather at a slight angle. The reticle is then not projected onto the actual point of impact - this leads to a deviation in the point of impact and the shooter misses the target.
In most scopes, there is no shift in the point of impact up to a distance of 100 meters, even if one does not look directly through the optics. However, when shooting at greater distances, the scope must be adjusted to ensure it is parallax-free even at long ranges. This is especially important for long-range shooting.
The assurance of parallax compensation is achieved through the manufacturing process.
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