You might consider trying the 240 SMK and US869 at about 101 -104g or so. Stablizes just fine out to about 1500yds according to reports on this site.
Edit: I'm at 3000fps over the Oehler with a 7-8 fps SD the last string I checked. 104.5g US869. Get up to 5-6 firings. Gonna try 104g and see how that works.
JonA, another member, is at 101g US869 with Nosler brass and doing a consistent 2970fps. Nosler brass in the 300 RUM has a bit less volume and seems to be a bit softer. Not sure what kind of case life he's getting.