I ran some 260 grain BT (not Accubonds) pretty fast but found that I was loaded too hot. Dropped back to 73 grains of R-15 and every thing was good. I found even 2,800 fps was too much for the BT and urged Nosler to beef them up or get rid of them before someone poked a cape buffalo with them and the buffalo objected. Incredibly they listened and soon quit the BT in favor of the Accubond which is a great bullet.
Many people slightly under load the 375 H&H for better performance and easier shooting. Like others have mentioned if you want speed go to the 375 WM for + 150-200 fps, the 378 WM or 375 RUM for + 300 fps. but this would put things over my comfort level and the bullets may perform less well at these velocities.
If you have to exceed 3,000 fps then the 235 grain and less bullets can do this with R-15, R-16 & R-17 and other powders as well.
