With match ammunition that upper should hold sub 1" grouping at 100. As mentioned the limiting factor is bullet choice and the ability to read the wind and apply the correction/hold. Do take a look at various bullets though-long range they make a big difference. Go to JBM and compare them and see what they do in the wind. I try to break it down further than the stated difference in drift at 600. So let's say drift is 2 mils for a bullet with a full value 10 mph wind, a 1 mph wind moves it .2, at/about 3" drift at 600-so a mis-judge of 1 mph equates to a 3" error on target. For info from Litz's book, 1-2 mph judging error is considered elite. Break it down further-if one bullet drifts .2 mil less than the other, that mis-judge above cost you close to a 1/2" less on target at 600. Doesn't sound like a lot but they (variables) all add up.
Bottom line-find an accurate and efficient bullet, drive it hard (fast)and read the wind well.
Check the new tipped SMK and/or the 75 Hornady BTHP since these are going to be mag length more than likely. Single feed-75 or 80 grain AMAX
Factory 77's-Blackhills
Factory 75's-Hornady match
While I can't speak for the new tipped match kings, the 75 Hornady BTHP at equal velocity will be more efficient than the 77 SMK-the numbers don't lie
JBM run theory numbers 10 mph full value wind at 600 @ 0 density altitude
77 SMK at 2900 fps(MK262 from my 24" bolt) 1.9 mils
75 Hornady BTHP match (factory) at 2750"" 1.8 mils
80 AMAX slow-2585 (reload) -1.7 mils-these are single feed
Big thing is look at the 77 smk velocity-that's smoking-if I increase the velocity of the other two-very doable-the 77 smk can't keep up ballistically.
the 77 smk at 2800 is 2 mils and at 2600-2.3 mils
Run the 1000 numbers and you see the 77 smk is an ok bullet, again the 75 bthp and or 75/80 amax is much better, no direct experience with the Bergers other than with .260/.308

