Old thread but... There are grub screws that hold the rings on the rails. You must remove the scope to access them. 2mm or 3mm hex key I think.
My ZR mount definately had some wiggle. Found all four of these screws had loosened up.
Tightening them definately improved the "wiggle" but did not eliminate it all.
I thought for sure that would solve my POI changes, but alas, I was wrong.
Very frustrating.
In my situation breaking in an RWS 54 magnum springer with PIO shifts I have run the following checklist to figure out what's up:
1) triple checked to eliminate paralax error
2) changed scopes
3) changed mounts
4) checked barrel droop
Still struggling.