You bohemia guys never get it right. Some of the iron sights of weapons are weird and dont represent the original. The MP5 in Arma 3 is even worse than the one in Dayz. This is how its supposed to look:
https://upload.wikimedia.org/wikipedia/commons/4/4d/Visierlinie.jpg
Your eye is usually very close to the first part of the optics, and then you look down the sight and when youre lined up the ring has a halo around it, When its all even on all sides youre good. When you turn the dial for the range the holes change.
The 50-100 meter one doesnt have a hole and looks something like this:
The only thing you have to do is carve a notch into the ring, so the ring and the pin are actually visible.
The Dayz and Arma MP5/G3 scopes dont really allow for good accuracy. I shot both in real life and I am not pleased about the ingame representation so far.
If anything its only a small change, but would increase the usability of the MP5 by alot.
The current ironsights ( 0.6) cant even aim at a certain point right now. Unless you know where it will hit.