Atticus cute off Heck Tate as He is speaking to Jem. What might Heck have been about to say, and why would atticus watnt to stop him for saying it?

Old Tim Johnson the neighbourhood rabid dog is on the lose. Atticus shoots him from far away. Heck Tate is about to elaborate on how good a shot their daddy is when Atticus stops him. Atticus does not want to be known for anything to do with guns. Guns are a symbol of violence and Atticus is also a humble man. Miss. Maudie tells the kids that at one time, Atticus was known as "one shot Finch".