Praxis made a useful comment on my 5.56 holdover infographic:
Recognize that the point of impact for all of these aim points is the 300 dot high center chest. So with a 25/300 zero if you take an aimed head shot at 100-200 you will miss high. The 25/300 zero is an infantry zero that trades an area hit probability gain and gives up near range precision. You can run trajectories through JBM ballistics online. MV, sight height, and BC are the most relevant inputs. For most realistic and effective engagement ranges for civies and police an approximate 50/200 zero is more practical.
It’s a good point, and it stands. The long and short of it is that soldiers with battle rifles should use the 25/300 zero, while CQM carbine shooters should use the 50/200 zero.
The 50/200 is flatter shooting. The 25/300 zero has a max ordinate (the highest point in the trajectory) of 6.69″ at 175m, with the M855 round. The 50/200 has a max ordinate of 1.99″ at 123m. Essentially, the 50/200 zero is point of aim, point of impact from 0-230m. Your drop is 5 feet at 500 meters, so this zero is very unsuitable for medium range targets.