I've been using FO sight exclusively on all my rifles that carry iron sights, some F/R, others front only w/peep, steadily converting them since FO sights came on the market, years ago.
As posted above, each human is a little different, in both their eyesight and the way they look at sights.
Added to that, some have no idea that FO front sight beads are available in the exact same sizes as their cherished Ivory and Gold Bead front sights ( 1/16"/fine and 3/32"/not fine
) and in two different colors (red or green) from various manufacturers like Williams, TruGlo, and Hi-Viz.
There can be a quantum increase in accuracy from a rifle just by switching from an open rear barrel sight to a receiver or tang peep sight - why do you think International target shooters use them when they're allowed ?
IMO, the reasons behind those having "problems" with a peep sight are that:
usually too small an aperture is used for hunting (often a small target arp ILO a larger ghost ring),
and ( the biggie) attempting to center the front sight in the peep aperture ILO simply looking through the aperture w/o looking at it, and looking instead at only the front sight, placing it on the target (game).
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