Well I spent literally 8 hours of today reading Zedikers "hand loading for competition" and B.L "putting rounds on target". I am now going to turn case necks (if needed), uniform primer pockets, de-burr necks and flash holes, Sort brass by weight, use his semi improved ladder test/ group test method at 500 yards using a 190 gr berger .000" off with .2 gr difference (300 WM) to extract a semi good load over a chronograph, to make watch for ES and hold an SD under 12, than play with seating depth to fine tune at either 500 or 700 yards.. sounds good in theory. Also am going to start annealing my cases ever firing.
Another good read is a article called IIRC - "Tales of the old Houston warehouse". After I read that I never uniformed a primer pocket again.
Is your 300WM chamber SAAMI spec? If so then don't turn much more off than .001". All chambers are different, especially the neck. For instance I had a DPMS 308 that had .011 neck expansion, which is ridiculously large, I was getting some split necks on the 2cnd firing so it would have been useless to turn necks for it, not that I would for a rifle like that anyway. Normal neck expansion is usually .007-.008". Still a lot IMO but neck turning could be beneficial still.
Anymore I'm only turning necks for my customs which have tight neck chambers, .002-.003" expansion and never get a split neck. Between annealing on my Benchsource and the necks being turned within .0002" of each other, there is almost no difference in neck tension. The last ladder I did produced a 5 shot .9" group at 400Y and all five were .1 grain different in charge weight.