I've been developing loads for my custom .375/06 improved. It likes IMR 4320, and both the 260 grain Nosler partition, and the 235 grain Speer. This is what I've come up with:

1) 260 grain Partition: 60 grains IMR 4320, CCI 250, 2625 fps into 3/4", 3 shot group.

2) 235 grain Speer: 62 grains IMR 4320, CCI 250, 2750 fps into 3/4", 5 shot group.

I think I've found my all round rifle. The groups are so close on the paper that resighting for each bullet is inconsequential.