Originally Posted by Tench
The smaller objective 24mm scopes give a greater depth of field and reduced px error, as the exit pupil is smaller your eye has to be more precisely aligned to the scope centre to see the sight picture reducing error. Exit pupil size is objective lens size/magnification.
That would make sense, same as shutting down the F stop on a camera.
It would be quite good fun to fit one to my 300, very "Enemy at the Gates"