I finally got around to chronographing some loads made up for my .270 using RL17. For lighter bullets there is a definite increase in velocity at the hotter end of the scale - 130fps increase to 3,550 using the equivalent powder volume of an H4831 load and a Sierra 90gn HP. Interesting but not much good for deer.
The results so far are less convincing for hunting loads, other than for higher velocity long-range hill loads. To see a viable increase in velocity, you need to be in the 3000fps+ territory to start with - good for accuracy and range but likely to give heavy meat damage. I suspect - as all of the US data indicates - that RL17 will give better results in the short magnum calibres like .270WSM rather than .270W.
I'll post up all of my data so far when I have a mo' this week.
Adam.