Using 180gr bullets, I sighted my '06 to be 3" high at 100 yards. That results in about 6" low at 300 yards. There are ballistic calculators online that can calculate that for you.
Using that knowledge, I took a big cow elk at 302 yards with one shot this past September. She was dead before she hit the ground.
That sounds pretty good dixi. My .300 mag is 2.5 high at 100, 4" high at 200, dead on at 300 and 6" low at 390. That is with 150 grain Hornaday interbonds.