Thanks for the comprehensive responses.

I tried a number of loadings based on the first post and I guess that 120gr as a maximum would work out well. The gun is far from rifle accurate so I that would also dictate loads.
One that would work well out to 150 yds is unnecessary if the accuracy limits you to 75 which is something that I should have taken into account.
Time to take it back to the range and see if I can manage any other improvements.

Che,ers

Tom