Swapping to a 168 grain Sierra MatchKing BTHP in my .308 for consistency at 600

Swapping to a 168 grain Sierra MatchKing BTHP in my .308 for consistency at 600 yards. Some folks swear by heavier bullets, but I've found this sweet spot keeps things predictable with that gold dot on target. Back when I was active duty, we learned that small changes can make big differences. Anyone else found their own magic recipe?