I've got a Remington Sendero 7 RUM that I'm trying to use for long range. I've got a Nightforce 5.5-22x56 on top mounted in NF steel rings and NF steel 20 MOA picatinny rail. I'm having a very hard time getting this gun to shoot sub-MOA. One day it will shoot a good, not great, group. The next time it won't hold them in a tea cup. Yesterday was a tea cup day. While sitting at the bench trying to figure out the problem, I tried wiggling the scope to make sure everything was still tight. It was rock solid until I got to the rear lens. If I tried to make it wiggle while looking through the scope, the cross hairs moved all over the target. I was surprised. Not so much that the lens moved because it turns with the power adjustment, but with the fact that the cross hairs moved so much. How do I know that they are staying constant when I change power or even shot to shot? I may be grasping at straws here. Would some of you guys try this and tell me if your NF does the same. I'm just having a hard time believing that I can't make this gun shoot. I've been shooting 700 Remingtons for 40 years and reloading for them just as long. This one is giving me fits. The only thing I haven't done it is bed the stock but it seems to be stable. I get no movement when I torque the front or rear action screw independently. There are only two new variables on this rifle: the caliber and the NF scope. I've never owned either one before. I'm thinking one of them is the problem.