Pretty much agree with Troubledshooter.

The Anschutz diopter is the model 6706 from memory but it mounts on the rear of the scope rails using an adapter block which are pretty hard to find. If you have a diopter to fit, whilst I don't have the adapter block I do have a suggestion that "might" work.

Webley listed two springs for the O/S, a weaker target spring and the std Osprey one, sounds like yours has the target spring.

I have one of the earlier ones with the std Osprey stock, whilst no HW55 or Walther LG55 its certainly a fun rifle to shoot.