[doorgunner69]

Using a ballistics program input with the AR sight height and M80 ball ammo I get -1.49" low at 25 yards with a 100 yard zero.

So it would seem just group 1.5" below point of aim. No zero crossing at that close of a zero. Investing in a laser bore sight is not a bad idea as well.

[eartick]

What I get as well...

[Okieshooter]

“
Using a ballistics program input with the AR sight height and M80 ball ammo I get -1.49” low at 25 yards with a 100 yard zero.”

Not all AR’s have the same sight height. I use taller scope mount, 3 inch sight height, I get 1.91 inches for 100 yd zero.

Also I recommend using a 200 yd zero for .223 or any high velocity round. This will give you a greater point blank range than a 100 yd zero. In other words you don’t have to worry about hold over until 250 yds or so.