The 66 has always been a problem for scope fitting in Australia. Hilver, lynx, Tasco, and Eaw mounts were options but I have always had problems bringing the scope back far enough for optimum eye relief. My answer is to buy Pecar scopes with the reticle in the Ist focal plane or fit scopes with straight tubes eg Kahles 1.1/2 to 4 or Leupold 1.1/2 to 5. Scout scopes or red dot scopes are another option.