There's not that much difference between H4831 and IMR 4831. I wouldn't think that you'd even notice the difference. Hodgdon shows only 1 grain difference in max loads for the 30-06 using 180 grain bullets. Also, with either of the 4831's in the 30-06, it's really difficult to even fit more than the book max load in the case. You could just fill up the case with as much 4831 as you can fit in it, and you'd be fine, pressure wise. Really the 4831's are too slow for the 30-06. 4350 is a much better choice, in my opinion. I like H4831 in my 270 but in my 30-06 I use H4350.