Mounting base needs to be shimmed when using factory screw. - Williams Gun Sight Ruger American .22LR Target Globe Front Sight w/ Attaching Base

I believe the screw well on the mounting base is drilled too deep. Using the factory screw to attach the mounting base I had to shim the base to secure it to the rifle. Without a shim the base is loose with the screw firmly screwed down. It was either a shim under the rail or a washer between the screw and mounting base. Since I didn't have a washer, I used a thin plastic material as a bed under the entire base rail. The thickness of my bedding material is about as thick as 3 or 4 sheets of standard printer paper. With the shim material in place the screw now holds the base secure with no movement. I have seen videos of others having this issue with the long barrel version of the Ruger American Rimfire rifle. Mine is the long barrel version.