I loaded 20 rounds with 69 gr. of IMR 4831 and had some trouble grouping two weeks ago. It was shooting 225 gr. Nosler Partitions. However, it was hot that day so I am not giving up on the load just yet. I want to try it again when it is cooler. I think some of it was me too as I was getting used to shooting from a lead sled.
I like a little faster powder in my .338wm, as like just about everything I own use H-4350 in mine, I'll sacrifice a little velocity for awesome accuracy.. I use the 225 partition or the 200 x-bullet, surprising they have almost the same impact point, no adjustment to the scope is needed..both shoot five shot groups around an inch, could be better but I can't handle it off the bench past three shots