I came across this nice online ballistics calculator and thought it would be good to share. You input the caliber, bullet type, bullet weight, B.C., etc. The default zero range is 100 yards: Click on "Advanced" to change the BZO distance. You can also adjust the tables to correct for up- and down-hill shooting, as well as compare two different bullets.
http://gundata.org/ballistic-calculator/
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