Re: the small sights on Colt revolvers.
My understanding is that the cap and ball revolver was intended to augment the rifle, since it offered up to six shots and the rifle only one.
The low sight made the revolver shoot high at close range, and about dead-on at 100 yards.
The late gun writer Elmer Keith, who knew Civil War veterans, once wrote that a good cavalryman could keep an enemy at bay out to 200 yards with his Colt Single Action in .45 caliber.
Sounds reasonable enough that cavalry and infantry of the Civil War could hit an enemy charging en masse out to at least 100 yards, perhaps farther.
The powder charge and conical bullet weight in the issued paper cartridges varied greatly contractor to contractor, for both sides. This would have made consistent shooting difficult.
All of my Colt repros hit dead-on at 80 to 100 yards, because of the small, low front sight. Consequently, they hit high at 25 yards, less so at 50.
"And lo, did I see an ugly cat. Smoke. Brimstone. Holes in parchment. And this ugly cat was much amused." --- The Prophesies of Gatodamus (1503 - 1566)