I have a 270 WSM, it doesn't seem to have any more kick that the standard 270 WIN. I also have the opportunity to shoot deer at 300 + yards, I use a 250 yard zero. I do not have the ballistic chart in front of me but can generall say that your point of aim/point of impact will be within 2.5" of zero from 0 to 300 yards. That will make your 400 yard adjustment somewhere in the 4 - 5" range, still not bad. I aim dead on with the 250 zero until I go over 300 yards, then I make an adjustment since I will have the time at that range, game tends not to be bothered by a couple of clicks at that distance.