I had to do pretty much identical method. I was loading the 195 eol in my 28 nosler. Found a load and at 100yards 5 shot group was 3/8". Went and shot at 400 yards and it opened up to like 14". Called berger customer support which was phenomenal and explained with these long bullets you may have to mess with seating depth. Reloaded several different oal and found where it was happy at longer distances while still being 1/2" moa at 100 yards. There is an article right on bergers website that explains all of this very well once the tech told me it was there
My loads are usually 10-30 thou off or saami length. I found nosler likes saami factory length, Berger’s and hornady eldx/eldm like 10k off, and hammers like 20k off. Just what works for me I usually can switch powder or adjust the charge a little and this works.
I usually do something like 30, 50, 70, 90, 110 and don't mess with the smaller increments. Seems to me like a bullet either likes to jump or doesn't. If it likes a further jump I will choose that over the closer seating. My 7 saum jumps 110 thou, creed is 70 thou.
I have been just going back from the lands in about 10 tho increments. I’m looking for good node that will be less than 1MOA across 10-20 tho at a minimum with the same POI. From there I’ll mess with .003 increments and usually find a sweet spot within a nice wide seating depth node that will be a forgiving load over the long term usually.
I have been doing this for a few years. I generally go in .030 increments to out to .120. One is usually noticeably better. I agree with above. The longer jump loads seem to be less sensitive to small differences in seating depth.
Depends on setup but with no limiting factors I do .010 increments from .010-.030 off, and then .020 increments from .050-.110 off and see what happens. Alex Wheeler talks about VLD's being pretty consistent to tune within .030 of the lands, and also somewhere around the .070 mark, and it's proven true for most of the testing I've done.
I normally start right at the .050 off mark. Close to the lands has always been finicky for me. If my bullet it really that picky that I need to tune .010 lengths I’d give up on it. For non vld bullets I just put them .050 off and start loading.
Lots of reading out there that more jump is becoming more consistent throughout barrel life.