WI Teacher:
I also have a Ruger 77 in 25/06, (medium sporter barrel); I bought it new at Bill's House of Guns in Merrill,WI in 1983 [no longer in business].
Anyway, I tried lots of powders and loads w/ the 75 gr Sierra and Hornady bullets for my annual one week groundhog trip to Ohio in the summer.
One day I loaded 57 grains of Norma MRP powder and the Hornady 75 HP and got super 3/8-1/2 groups. As noted these days, RL 19 will work as well if not better.
For deer, I used the 120 gr. Nosler Partition or the Hornady 120 gr. Interlock w/ 50 grains of IMR 4831.
For the 90 gr. HPBT, I used 55 grains of IMR 4831 and/or 47 gr. IMR 4064.
All of the above loads were with Remington and Winchester cases and CCI 200 non-match primers; work up to similar loads in your rifle. The 25/06 is a great chambering.