In my experience it seems to vary by rifle. My most recent 6.5x284 build using 140 VLD's gives its best precision at .020" off the lands. It erodes quickly past .030" and below .010" as your statement suggests. My 300WM gives similar results. I think it still has to be tested because I have two other 6.5x284's that are optimized at .075" off the lands and the window is very narrow at less then +/- .010".