A couple of years back I was faced with the same problem ; old eyes and open sights , so I made a scope mount/fore-end which clamps on to the barrel immediately in front of the action once the original fore-end was removed . I used it to good effect on a 32-20 Low Wall and a Martini 310 .
I posted the project in another forum . Here is the link .
http://www.homegunsmith.com/cgi-bin/...3;t=23311;st=0