How far do you expect to take shots ? JBMballistics.com gives you the ability to select your bullet from the library, input the mv, select your max distance and select the distance intervals. You need a good indicator of mv from your barrel length, not what is expected from a .223 with a 20'' barrel.
The beauty of a program is that you can vary the mv and see the effects. Many folks use the 'max point blank range'. Your max distance is defined by not having a bullet exceed 3'' higher or lower than line of sight. If you expect small targets you might elect + or- 2''.
After you are near point of aim at 25yd, move to 100yds for your work.