Thanks ,Kuduae,
The important points you make are
A-Snug fit ( to avoid movement of the scope ) and
B-Rear base slightly out of position initially so that careful filing can produce a snug fit , no movement .
C-Yes . Recoil taken by front mount .
All that is very helpful .

The rifle is a Zi-di ( Ziegenhahn and Diem ) in 5.6x35 (hornet )
Regretfully the rear action ring will have to be machined its not uncommon to do that I notice .

Thanks to all who responded .
I shall now attempt to upload photographs for the first time .

[image] http://i1369.photobucket.com/albums/ag219/miers4543/2014-01-11014_zps53083077.jpg[/image]