Increment of load search
Five grains of powder is way too much of an increment to find a good load.
Start with the minimum published load (in your loading manual), for that powder and load 5 rounds each. Load another five rounds with .5 (half a grain more powder), another five with .5 grain more than the last, etc. Keep incrementing by half a grain until you find an good group, or until you either began to get pressure signs or you reach the maximum powder listed for that bullet in your manual.
Before choosing a powder to work with, ask 25-06 shooters (on this forum), which powder, load and bullet gives them the best results so that you get some idea what is likely to work well.
Addendum: I list the number of grains of powder and other data on a white envelope and seal those rounds inside until they are shot to keep them all separate.