Originally Posted by Conor
If you bring it down to 7yrds (for whatever strange reason you need 7) you will definitely obtain bigger gaps between your ranges 50-55.
Are you sure Conor? - I have tried this on a MK1 and Mk3 Nikko and found that bringing the focus range closer (from 10 yards to 8 yards) actually made the gaps at the top end smaller.
I have not tried it on a Big BSA though.