Okay, I'll agree to disagree with you. I see a terrific improvement over using an original notch rear sight, not just on well defined aiming points but in general field work as well.
The comments on a handgun may shed some light on the situation, perhaps the effect lessens the further away from the eye the aperture is placed. On my three rifles so equipped, the rear sight is approximately 15" from my eye. On a handgun that sight is some 26" away. I've already noted that the barrel mounted peep isn't as precise as a receiver mounted peep and that lessening could certainly be directly proportional to distance, but the centering effect is definitely there. You mount the rifle and focus on the front sight only, the eye still automatically centers it in the aperture which is just a fuzzy looking hole. Like any peep, your eye isn't shifting focus from the front to rear sight continuously. One caveat, obviously, is to match the aperture to the use. A small .05" or even .09" diameter aperture won't work, it requires what amounts to a ghost ring sight.
I've only tried it for me so can't say how someone else would use it but to conclude that there is no benefit at all for anyone - on a rifle - I cannot agree with that.
