Varminter,
I agree with ricciardelli about the 140 grainers. I have used both brands of 4831 with 130's and 150's for the 270 Winchester, and the Hornady 140 BTSP is by far the most accurate load I have for a couple of Model 70's.
I suspect the 4831 will be much too slow to be efficient with the 90 grain bullets. Pobably can't get enough of it in the case to do much good. A slightly faster burner such as 4064, 4320 or maybe even 4350 would probably be better. Good-luck...BCB