The Bushnell 3-9x40EG is legendary for being "the working man’s scope"—affordable, bright, and tough. But its affordability comes from simplicity, not hand-holding. The manual translates that simplicity into accuracy.
The manual explains that the (the one near your eye) is adjustable for your vision.
Turn the rheostat dial to "R" (Red) or "G" (Green). The numbers 1-5 represent brightness levels.
This allows you to dial back to your exact zero even after field adjustments. Lose the manual, and you might strip that tiny set screw using the wrong tool (often a 1.5mm or 2mm hex key, as noted in the manual).
The 3-9x40EG illuminates the reticle, which is beneficial for dusk or dawn hunting.
If you are looking for specific, in-depth tutorials on how to adjust your scope for different weather conditions, or perhaps you have questions about which mounts would best suit your rifle, please 985-bushnell-legend-series-manual.pdf - Balistas.cz