I really like peep sights. I have them on several deer rifles and my two air rifles. As far as deer go they are not a difficult target at the ranges I hunt, usually 100 yards or less. My Air rifles, one an FWB 300s has the original match sight and is geared towards the 10 meter bull. I sometimes use a little bigger insert in the front sight so I can keep the bull in the ring so I understand the correlation between insert and bullseye size. The other day I was getting bored with the same target, not that it wasn’t a challenge, I’ll never master them, but I wanted a change. I got a deck of cards and tried to hit the symbols on them with the circular aperture and it didn’t work out so well. Haven’t tried a post but I really couldn’t see them too well so how can you hit what you can’t see? I’d like to be able to shoot flies and I know this rifle will do it too. Do I change the rear aperture to something smaller perhaps or will I have to scope it to accomplish this. Please educate me on these sights and what I can accomplish with them. By the way, I’m 69 and wear progressive bifocals. Thank you.