Is there really any way to have your most "accurate load" that doesn't also result in your least ES?
It's pretty much a law of physics that your vertical spread of rounds is going to be greater with an ES of 80 than it will be if your ES is 20. But it also has to do with the distribution of that ES.
Also, ES must be coupled with SD. You could have 19/20 rounds with an MV of exactly 2,750 fps and if round 20 of 20 is 2,670, you've got an ES of 80. Round 20 of 20 could have been off for a number of reasons. In that scenario, I whould be ecstatic. I would just discard case 20 of 20 and go shoot a match.
If you're going to win matches at 1,000 yards, you've got to come as close as you can to and SD of <= 6 and an ES of 20... on a consistent basis.
And we're only talking the vertical here. You also have to learn to read the wind. In my last 1,000 yd match 17 of 20 rounds would have been 10's vertically. Shooting in the 3rd relay and not being an expert (not even good) at reading the wind, I finished about mid-way down the list.
So, how do I get my vertical minimized?
1) Meticulous case preparation (details if anyone is interested)
2) Powder measure accurate to .02 grains (GemPro 250 and/or AccuLab 123)
3) Bullet runout to +/- .002 on the dial indicator (Hornady guage).
4) Lapua brass
5) Berger bullets (on the lands)
I shoot .308 F/TR using a 185 grain Berger BTHP