I have the same problems with how-much for my 270 using 140 TSX and IMR4350. I called Barnes and they said to go with 49 to 53 gr, working up in .5 gr increment. For 30-06 and above they said I could go 1 or 2 grains over Xbullets. Below 30-06 you should not go that strong. I started out with 52.5 grains and it was a mild load. Then I went to 53 and I could tell the difference. Going to try 53.5 gr next. But that will probably all I will go.