I do not know exactly what velocity you are shooting you 400 gr bullets but think about this.
Using a 400gr RN at 2200fps for example, if you zero at 150 yards your trajectory will be about as follows.

50 yards 1.1" high
100 yards 1.7" high
150 yards Zero
200 yards -4.3"
250 yards 11.6" [about a foot]
300 yards -22.2" [about 2 feet]

Very easy to remember, just in case you see a good plains game animal at a distance and want to make the shot.