Hello, Tim and welcome to the site! For opinions on optics and ammo, check out the sub-forums devoted to those two topics. Or you can use the search button for them as well.
In the US Army and USMC, irons for the M16/M4 are zeroed to 300m using a 25m scaled silhouette. Iron sights for the modern AR10 are very similar, so the same standard can be used.
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