I remember my dad had a chart with the "close range zero" for several calibers. Seems he used 27 yds for his .30-06 Springfield...his deer rifle. I don't know what happened to that chart. It gave the yardage for zero, plus, plus, zero, minus, minus for each cal listed. I wish I still had that chart.
...even a blind hog finds an acorn every once in a while.