For the area I hunt with my 223's I usually sight high at 3" at 100. I don't mind shooting mid and hitting at head in closer distances.
Though the advise given is good , have a sight in a 100 and check it in real distance at those you are going to shoot at.
It's a good habit if you are developing a load to actually experience the drop and POA at the distance you are looking to shoot at.
-Aaron