When first mounted the main screw was too long, so I added a lock washer to the outside of the plate. Even that is not always enough to keep the unit tight however. It needs to be checked regularly for tightness. If tight and sighted in, it shoots well however. Locking screws on the leveling screws are a good part of the design.
Pros: Probably the only and thus most reasonable rail mounting solution for this gun design
Cons: Not an entirely stable scope mounting platform because it loosens up from firing a while
This review was written in the old system and had content requirements that are different than reviews written today.