JJ's load for a Heym A-frames 79.0gr IMR3031 with 2gr Dacron over filler or one of the commercial plugs!
For the Break-Away solids Bill (owner) at Swift said reduce load by 1.5-2gr, He said about the same
'Reduction in powder charge for most bigger calibers and I've found that works well in 450-400 double
and 375 H&H and 416 Rigby!
In all 3 of my doubles that formula with very little fine tuning gives same point of impact and same in the bolt guns.
Hope that helps! Knowing what gun u own and what loads you have been able to regulate with would help! I have a lot of data I've tried in the 470NE and so I happy to share my experience.