rollingb..When I work up a load for a new rifle,I start with no compression and load only ten at a time. from there I increase the compression by .050.You will see the groop shrink someware down the line,when it get larger again go back to the last good groop and cut that by .025 and see what happens.next I work with the primers,then bullet and alloy.
I know that is a long drawn out affair.Then again you might find one right off.
I have a .45-70 Browning I thought I would never find a load for that I was satisfied with,but it shoots now with slight changes once in while when things change,like climet or powder.
If you like to do it by weight instead of volume go with a 1/2 grain at a time.
I like to use a dipper I cut from a case then drop tube it seat a wad and compress it.
Just something to think about