I just tried a 454190 in a R-P case to see what the max load of Trailboss was using the "to the base of the boolit" method. I got a measured max of 8.7gr which gives a 70% starting load of 6.0gr.
My Lymans Cast Bullet Book lists Trailboss with this boolit Max at 5.8gr.
8.7gr vs 5.8gr is quite a difference. Using the "base of boolit" method the min 6.0gr measured is over the book max. Any thoughts on this?