You must be assuming that the shooter can shoot, and that the rounds used are in the low single digit ES numbers, correct? Because at, say, 1,000 yards you can have a rifle on a brick shithouse rest where it simply cannot move. Then you can send 5 rounds through paper and easily print a sub moa group. Then dial up to 1k and send 5 more and print a 20" plus group, and it could be wind variables or ES issues in the ammo. Heck, a 10mph cross wind on shot one that dies on shot 2 and is not accounted for will kill your sub moa hopes in a hurry! That would be a 50" miss. And If mv dips by a mere 20fps it'll also hit 5-6" low.