This is not so simple. First, elevation is cammed for NATO 5.56. There are many versions of this round from various countries, all interchangeable for functionality, however trajectories and accuracy vary. I have never used a cammed elevation scope and am not a fan, as other factors affecting actual trajectory are barrel length and manufacturing tolerance variations.
Service Rifle used to be shot with standard rifles, iron sights, then Elcans and now, anything goes. The IOR M2 may be the best 4X sight available, but the shooter will probably have to aim off a bit, especially at 500. There is the advantage of quick adjustment, with no memory or notes, except for aim off and the optics are high quality, as is construction.
Debate?
Peter