I just got an "Open Box" Steiner 5-25x56. I mounted and zeroed the scope yesterday morning. Yesterday afternoon, I attempted to set the zero stop but where the two screws go in the elevation turret all I can see is threads. It looks like the screws have come out. Same thing with the two screws on the windage turret. Also, what are you supposed to use to loosen/tighten these scews? Are they "inside" the turret and I just can't see them? The scope adjusts correctly and nothing seems loose. Please Help!