Re: What's more important, ES or Group Size??
J E Custom is right (as usual). You need a balance between group size and ES. To determine how small an ES you need, just run the numbers....
Lets say that your 7mag shoots .5moa groups with the 168VLD at 3000fps (average), with an ES 32. Check the variance at 800 yards with a velocity of 2984fps and 3016fps. Then, depending on the variance you can determine if that variance is too much for the target at which you are shooting.
Continuing the example, lets suppose that this velocity variance provide you with a .25moa variance at 800 yards. This doesn't seem bad until you add the average .5moa group. This would mean you have the possibility of a .75moa variance at 800 yards. that's roughly 6" and is outside the the magic 8" kill zone on a deer (remember, you are shooting at the center of the kill zone, so it's a 4" radius). In this example, an ES of 32 is too much. You would need to roughly cut that number in half to 16.
Generally speaking, I look for .5moa accuracy (or better) with an ES of 15 (or less) in nonmagnum cartridges.
I'm not gonna shoot here. I'm gonna shoot waaaaaaaay over there!