Started this one because of a question in another thread. The question was "Why do you need a scope on a shotgun?" Ans. Because I am old. Really.... My reading vision began going bad at age 40 and now it is about a correction of 3.0 at age 48. And since then, my distance vision deteriorated as well. So now I have bifocals with a fair bit of both short and long range correction. So, when I look down the rifle sights with the naked eye, I can't focus at all on either the deer or the sight pin. And when I put my glasses on, I can either see the deer or the sight pin....depending on which part of the eye glasses I am looking through. And it doesn't work to try and bob your head up and down. Scopes solve this problem for me. The reticle is in focus and so is the deer after it is adjusted. I have my aim back.....maybe better than in my youth. I don't really understand how it works, but it works great. My crossbow has to have one also. Without it, no chance at all. I don't know if it just the reading vision thing (age), or whether it applies to near-sighted and farsighted conditions as well.