Another scope question. When I took the Bushnell AR 4.5x18 scope out of the wrapper, a little dime-shaped piece of aluminum with a "B" embossed on it fell out. I assume it goes in the rangefinder turrent, but I don't see any way of holding it there. Without it, the turrent shows a bright steel screw/cap with a coin slot. The instruction manual says the turrent cap should be solid with a hex screw holding it in place. Doesn't sound like this turrent at all. I assume I would loosen the screw/cap and turn the turrent to reset zero, then retighten the screw. But do I have a faulty turrent cap, or is that "B" disk to be removed [or held in place some way]? It just fits the opening in the rangefinder turrent, but not tight enough to stay in place. I might be able to use double-sided tape to hold it in place.