Ahem, the reason sixgun gurus like Elmer
Keith put adjustable sights on their shooting
irons was so they could adjust to all sorts of
loads and distances.
What, bottom line, do you really expect a fixed
sighted sixgun to do? Without the exact
right load for a given distance and velocity,
you'll never be dead on with a fixed sighted gun.
I think Wyatt Earp said it, or maybe he never did,
but the practical distance for a handgun in his day
was 15 yards. But he did say you could certainly
worry a gent hundreds of yards away by lobbing the
rounds.
By the way, those who saw Elmer Keith take out gallon
jugs at pretty far distances noted that he sometimes
would "walk" his rounds in before getting a hit.