If I want to be able to shoot out to 250 yards without having to compensate for the long distance, how high would I have to sight my rifle in at 100 yards. Would it be worth the high aim at 100 yards, or would it be so high at 100 yards that sighting in to be dead on at 250 wouldn' t make sense?

get volume two of Horndy' s handbook of cartridge reloading...fifth edition.....all the data is in there.

It' s all based on the ammo you choose and the ballistics for that particular load. Here' s two examples for Remington loads, but you want to look up the ballistics tables for the specific bullet you' re choosing.

120 gr HP
Short-range trajectory: 100 yd .6 high; 150 yd 0; 200 yd -1.9; 250 yd -5.3
Long-range trajectory: 100 yd +1.4; 200 yd 0; 250 yd -2.9

140 gr SP
SRT: 100 yd +.7; 150 yd 0; 200 yd -2.1; 250 yd -5.7
LRT: 100 yd +1.6; 200 yd 0; 250 -3.1

Basically, you should zero to 200, and you don' t have to concern yourself with 250.