I think that Atticus keeps his marksmanship a secret from his children because he does not want them to grow up knowing that his achievement was being a ‘dead shot’. I think this because Atticus realised that this was a skill which he could possibly abuse.

‘down at the Landing when he was coming up, if he shot fifteen times and get fourteen doves he’d complain about wasting ammunition’

This shows that when Atticus was younger, he was confident enough in his shooting to get all the doves but I think that he missed on purpose. This may be because he doesn’t want to abuse his ability and kill all the doves in cold blood therfore making the excuse of missing the last bullet. Linking this back to not telling his children, I think he did not tell them as his humbleness over the years and didn’t want to seem arrogant to his children as this could make them boast about their father’s achievements. This was shown when Miss Maudie told Scout that her father was ‘One Shot Finch’ and Scout wanted to tell her friends at school.