Here is an S&K Item #1365 mount & rings I put on this 1941 Lithgow over 10 yrs ago. Rock Solid thru 500 rds of surplus ball. They are kinda pricey but work real well.
Good advice about taking it to a gunsmith. Unless you have a Dremel and know how to fit them, (if your rifle needs it) they can be toast real quick!
Good look'in old rifle ya got there! Ken