Sighting in for the range where you normally shoot 90% of your game is not arbitrary.
Setting sights for a maximum 3 inch rise is a good method for
having a flat shooting rifle out to X yards. After that, you are back to holding over. I do like the Burris BP reticle, which have on 2 rifles, with zero set at 200 yards.
There are several different right ways for different people and hunting situations. And there are several wrong ways that people read about in a magazine article or an Internet forum, that will not work for them at all.
A sight setting for a .30-30 and one load is easy.
A single sight setting that will work for a .270 or .30-06 at 25 to 400 yards with a wide range of bullet is a bit more complicated.
If you intend to take shots at 300 yards or more, but might have one at 100 yards or less, the surest thing to do is mount a fixed 6x or 10x power scope with target knobs, sight it in for 200 yards, and learn how many clicks to move it to hit dead on at any range.
