I would choose the prone postion with a bipod and a flat area to lay upon. A nice flat shooting rifle with no wind or mirage:
If I've been practicing and know the rifle/load well I would say I could hit it with confidence on the first shot. I've practiced at that range with a few rigs and have been able to keep em in the kill zone especially if I knew the range.
If it was an unknown rig/load or one that I have no experience with, then its a gamble for sure .
Out past 400yds, if its windy or hot (mirage) is where things start to get interesting..................
MtnHtr