Good to see that you've finally found the sweet spot for this one Doc.
You can have a bad time for some calibres' & whatever you do just seems to all go to pot!
Sometimes a simple powder change can lead to a complete reversal in fortunes & then Eureka.....success.
It's a sweet feeling!
I had the same issue with my .308 Norma Magnum.
Great article mate - hope to see more from you.
Cheers
93x64mm