Seating depth

[Gord0]

300 win mag, virgin Sig brass, 72gr H1000, 200gr eldx. Essentially zero wind today, 100m, bipod and bag off a bench. Tested 4 lengths to fireform brass for load development.
Which would you go with to start doing a workup?

 

[Okanogan]

Your post doesn't say how far off the lands you are or if you are working of a COL limit from magazine length.

Before I sent my 300 WM rifle off to be re-barreled, I was having reasonable success (1/2 MOA) with 200 gr ELD-x at 0.020" off lands
79.0 gr H1000
F215
Norma brass

 

[Gord0]

Sorry, forgot to add that I'm trying to keep this mag length. I started at max and worked my way in. Stock Savage 110 bedded in a Boyd's.

 

[Mikecr]

Your groups didn't open or close much at that distance. Your 'lengths' need to be CBTO, not COAL. Land relationship doesn't matter, just best CBTO.
But try what you're doing at 3.410 & 3.430