Hornady lists the following, (7th edition)
HDY 158gr XTP bullet.
H 110 Start: 12.7gr WSPM primer
H 110 Max: 15.6gr WSPM primer
I am currently loading 14.5 for my loads with this bullet. It's strange that some loadings give the 3%, while others give quite a range..........
?
When I get a minute, I'm going to go back over my manuals and update my load book,
I'm assuming your flatpoint may have a different cannalure and seating depth..
Ben