This is a pretty common problem with rifles, centrefires in particular as a lot of the Moderators tend to be quite fat.
As already suggested this is probably reflected light from a mod or perhaps the barrel.
Lots of possible solutions, angle the lamp up a bit, use a dimmer switch, try a filter on the lamp, sling the lamp under the barrel, or to the side (but this can cause distance problems), cover the scope/barrel with non reflective material, black insulating tape over the bottom of the light lens, flip up scope cover UP on objectice lens, etc etc, some or all of the above will "prob