How long ago did all this happen and what Cabela's did you return the scope to? Not sure if Nikon can get the scope to check it out or not. Like I said, I have 3 and have over 1000 round's under all of them.
Very surprising that you would have a problem with Nikon's BLACK X1000 scope. Looking at your rig I would be more inclined to think it would be related to the P-Series mount's you used. I'm not sure why someone would put a $750 scope on a rifle with sub $50 mount's that have only one lock up...