[–] hobbidlybzi 0 points 1 point 1 point (+1|-0) ago
https://www.military.com/join-armed-forces/marine-corps-weapons-qualification-course.html The US trains marines for this. With iron sights. Check out: https://www.trngcmd.marines.mil/Portals/207/Docs/wtbn/MCRP%203-01A.pdf look for "Holds for Iron Sights at 300 to 500 Meters/Yards"
https://www.wheretoshoot.org/ Put your area in and filter for 500yds+
https://invidio.us/watch?v=jJ3XwizTqDw <- That is exceptional. Doing that prone with a rifle just takes practice.
[–] Karnivor 1 point 0 points 1 point (+1|-1) ago
None of that says anything about being 1moa from 500 yards. Just that they shoot that distance. You'd be a good shot to be on a body sized target at that distance.