so i went to the gunshow in puyallup over the weekends and bought some stuff. one of them's the NC star mark iii tactical scope/red dot (the 3-9x scope with the additional red dot sight) it seems like the knob for illumination is really hard to turn, my inger tip hurts just trying to turn it. How do i adjust the tightness/looseness of it so it's easier to turn? i cant seem to figure it out. the manual does not mention anything about it either. no brand bashing!