thanks for all the comments i found a cantilever mount on e bay and have solved the problem some were silly money but if you go through all the posts eventually you will find what you want at a reasonable price. there is nothing special about the scope (nikko sterling) its the length of my arms and ...

i too have this problem i have moved it back as far as i can get it but it still needs to come back further i did wonder if extended mounts were the answer but i dont know where to find them would be grateful for any suggestions'thanks in anticipation