I pick a bullet, touch the rifling, pick a powder, Find a max load in a book subtract 4 grains, load three shells, add .5 grain, load one shell, add .5 load another etc. until I have 10 total. Just before dark when the winds calm down I set up a spotting scope and two targets at 300 or 400 yards.
Fire the first two as sighters, this fouls bore and dial scope to last shot. Fire the 8 remaining shots, from least to most powder, at the other target marking down on a target at the bench the order in which they went in. If you get pressure signs stop. Read the clumps, they should tell you what the rifle likes for speed with that combo. If you don't get a clump try a different powder. If they are just starting to "come in" at the highest load I will continue up a bit more. Here is an example:
Notice it liked slow and then the last 2 rounds started going out. I picked load 5. Then I do four or five shot groups doing variations off this base, adjust seat depth, swapping to regular primers, changing neck tension, at 100yd. If one is showing improvement, I do another ladder with .3 grain increments, half above and half below my first crude node pick. In this case I'll go out to 400 as the whole ladder is just over 1 moa. [img]/ubbthreads/images/graemlins/grin.gif[/img]
Works good. Good luck.