All shooters have almost a universal lack of range estimation ability. Everyone should be able to kill game within 20-25 yards. If not hunting is not for you. Most people drop off very quickly beyond that point. Have you measured 35, 40 or 45 yards and then seen how small a bird looks at those distances? Different backgrounds make ranges even harder to judge. If you can correctly figure the range to within two to four yards you can then figure out the correct amount of lead. If not you are just spot shooting and any long range shots are pure luck.

Just like most 250 yard deer shots pace off to only 175 or so yards most 40 plus yard shot shrink when measured. Worse is that many figure it from where the bird is recovered which may be a long ways from where shot. Range is a tricky thing to some and a real mystery to others.