That’s what happens when somebody has zero clue what they’re doing.The other day I shot a friend's AR rifle, a flat top with a SiG Romeo red dot sight mounted on it.
He does all his shooting at 5 to 15 yards to simulate combat conditions in and around his home. So, he had chosen to zero the rifle to be dead on perfect at 7 yards.
Well at 25 yards it was quite high (but still usable if you knew where to hold well below the target).
But at 50 yards we determined it was shooting about 4 feet high and 100 yards it was hitting 8 feet above the point of aim. This was ridiculously high --it basically made the weapon unusable at those distances.