hmmm maybe if I try explaining a little differently...

My round pinguard appears just a tad smaller than my peep when aiming. This produces 3 different sized circles that I can actually seewith good clarity innatural sunlight- the outside perimeter of the peep, the inside perimeter of the peep, and the pinguard. Because the pinguard is just a tad bit smaller than the inside perimeter of the peep, I center the pinguard inside the peep. I'm then anchored and aim and shoot.

When shooting indoors, it's more difficult to see both the inside and outside perimeters of the peep making it harder to center with the pinguard. Also, because of the poorer lighting, the inside perimeter seems to get bigger which produces slop in my sight picture when trying to center the pinguard inside the inside perimeter of the peep.

I'm thinking this just has something to do with light diffraction and nothing can help it. Have I completely lost everyone? LOL sorry, thanks for trying to understand though.