Rod, Ayoob's formula is aim at the chin. I also have a S&W 640 2" .357 that I can shred a 1 gal milk jug with at 100yds. It's not the gun, it's the shooter.
With this I can do the same at 300-400 yards. Not quite as well as I used to, now that my eye sight is going T.U.
S&W Mod.57 .41 mag. 8-3/8" Barrel
Ron