Apparently the rifle was dropped on the sight or something dropped on the sight. The elevation knob was bent and turns in a different plane that it was designed to do. when the lower edge reached the lock tab, that was as far as it would go. More forceful turning just locked it more. I took both screws on top out, pressed the sight down against the spring tension, and was able to turn the knob. I have straightened the knob bolt somewhat and it is adjusting now. Thanks for the help.
Charlie
