Thanks for your data!I was running 78.0 Varget under a 260 Partition at 2,800 ft/sec. Accuracy was very good from my 20" Ruger Guide Gun.
Two shots went completely through a buffalo and were both caught in the off-side hide. Picture perfect expansion.
71.0 Varget achieved 2,500 ft/sec with the 300gr Partition but they weren't accurate in my rifle and I never tried a heavier charge. I think you could easily exceed 2,500 ft/sec.