tim, welcome. best powder I have found for the 25-06 is IMR 4831 or the SC offering of the same powder. The SC (short cut) meters much better for thrown charges. As for charges, with a 115 Nosler BT the best for me has been 51.7gn and clock at 3150 out of a 26"bbl. I'm seating .025 off the lead. According to my books this is a safe load but on the high end of the spectrum. 48.5gn of IMR4350 is my #2 load and it runs at 3100fps also safe but on the high end. Primers are Fed 210. As usual load with caution, consult reference books etc, for all you know, I'm just some moron with a computer.
Good luck,
~z