Sight target at 300 meters. Shoot. Observe your point of aim and point of impact. Note that they are the same.
Sight target at 200 meters. Shoot. Observe. Repeat at 100m. Note that POA & POI have relatively little shift. This continues all the way to almost point blank. At point blank there is a height over bore offset, which should be there, as the optics/iron sights are higher than bore.