It seems that I can find 20 different ballistic charts for 5.56 rounds. They can be had for different bullet weights, barrel lengths bullet types, etc.

But just finding a chart for a 16", 123 grain 7.62x39 round results in a wade through fuzzy math and confusing data.

Does anyone know of a link, source, etc, for a genuine trajectory chart for zeroing. I'd like to compare various battle sight zeroing and not just here "well I zero at #$#$% so it'll hit at #$%#".

Any help?

www.sportsmansguide.com/resource/remington_charts/762x39bal.htm

This may help you out.  It seems this round is a bit like throwing rocks.  

www.headsbunker.com/html/article_trajectory.html