I found this out this year. When TSX bullets first came out, the new manual was not out yet. I called Barnes and they told me that the TSX max loads were 2 grains higher than regular X bullets. Thjey also gave me some loads over the phone.
This year I was loading some rounds for my dad's 7mm Rem Mag. 140gr TSX with, I believe 70 or 72 grains of RL22. I had it written down in my older manual and on the box of shells. Later on, I checked the newest Barnes manual and saw 66 grains was their maximum load. Wow!!! What a difference!!!
White Oak Lodge