I am trying to zero a 20inch rifle with NM BUIS sight base. Now I know you go one click past 8/3 on normal sight and zero at 25 meters. And once you are done you return it back to 8/3.

My problem is what is the incremental diststance value since the NM is in 5,10,15,20 insteaid of the usual. I assume it will be just once click past the value as well? Please someone help me solve this question.

Ok can i please be directed to a site or someone that could help?

Have you read thr BUIS FAQ?  A lot of info there.  I did not review to see if your specific question is answered, but there should be enough to draw a conclusion.
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