I bought a SA standard M1A from a friend a couple of years ago. I hadn’t shot it since I bought it, so I took it out recently to kill some paper.

The rear sight elevation and range dial kept shifting on me when I was shooting. I don’t have a lot of experience with these rifles, but I think that I have the rear sight screw tightened enough, it doesn’t seem like I can tighten it anymore. The range dial does not move independently of the sight.

Is there something I am doing wrong? What can I do to fix this?

I had the same problem with my SA M1A Scout rifle, called SA and they said I would have to send it in. I did. They fixed it and sent it back no charge. Hasn't happened since then.

your pinion(windage) and elevation knob are loose....you need two screw drivers to tighten....one on each side....if you over tighten you wont be able to move the knobs with your fingers so tighten a little and check it

Thanks. I hadn't tried two screw drivers. That seems obvious, I wish that I had thought of that.