One of the most common user errors is failing to set the diopter correctly. The manual dedicates a critical Step 1 to this process, which many skip:
: Rotate the power change ring (near the eyepiece) to the desired setting between 3 and 9. Note that for ballistic reticles to function properly, you should typically be at the highest magnification. Illumination Control bushnell 3-9x40eg manual