Relatively new to air guns (Beeman R9), but one suggestion. Vibration is capable of unwinding every screw attached to those units. Literally check every one before beginning a session.
exactly. this is what happened to my R1. i loctited everything down real good and it broke through that too. my problem was always a wandering zero. either the OP has a bum scope or screws are loose on the gun itself or the mounts.
