To get the aperture, centering effect, the hole has to be close to the eye. Mounted down on the barrel you have a hole, which is just an alternative to a notch. One may work better than the other for a given situation or shooter.
I was curious about this and got a fairly good discussion and pointers to literature when I asked about mounting a peep on a hand cannon pistol or long range single shot pistol. Bottom line, ZERO, benefit and nobody does it. I am sorry, I dont remember where I was. It is not a question of less benefit, there simple is none. None with regard to the aperture. Might be just the ticket for an individual for some other specific individual.
