It's funny, ACOG were designed & precalibrated to take out men at up to 800m, an even smaller target?????
Marketing BS. Try it before you buy it.
Trying to kill an animal humanly is not the same as "taking out"
men at 800m, whatever that means.
With ACOG (3.5x) it will be more luck than skill or optics to
wound 20" wide subject at 800m. M14 with ACOG is not the tool for a
long-range work regardless of what the marketing brochures tell you.
There are better rifles and scopes for that type of shooting.
If you use M14 with ACOG and keep shooting all day, you might be able
to hit something at 800m, not sure what, when and where.