I am Returned!
A quick review of this Thread, largely well covering most all points. But just to add one dimension NOT particularly covered. First just the side note that "Scopes" and "iron: sights are really two differing creatures, with their unique virtues, vices and applications.
Iron sights of two major divisions as "aft" sight either barrel or receiver mounted and we've well discussed nuisances of the perpetually termed "peep sight" genre. What wasn't well covered at all was a greatest virtue of the receiver mounted sight versus aft barrel mounted. "Sighting radius". Really quite important 'leg up' in addition to the other principal "peep sight" advantage of 'framing the target' as the human eye literally allowed to focusing entirely on the muzzle sight.
The aft barrel sight is a rather poor substitute at range, but remains entirely superior for short range "snap shooting" or where such obstacles as brush make it most handy/convenient. Anyway, any receiver mounted sight offers its rather huge advantage of often about twice the sight radius and is notably superior for such capability "within its realm where extra moments in acquiring and retaining "sight picture" are to be afforded.
My take!
Best!
John
