In what chapter does Angus Tuck prove that he is immortal?

In chapter 7 of Tuck Everlasting, Winnie learns the story of the Tuck family and how they all found out that they are immortal.
Winnie meets Jesse Tuck when she sees him drink from a spring. He tells her not to drink from the spring because it would be bad for her. Winnie is insistent about drinking from the spring, but more of the Tuck family stumble upon the two and carry Winnie off to explain the situation to her.
Mae, Miles, and Jesse explain to Winnie that they came to Treegap 87 years before, and they stumbled on the same spring that Winnie saw Jesse drink from. They noticed that the water tasted strange, but they did not think too much of it until strange things started to happen to the family. Jesse fell out of a tree and ate poisoned mushrooms, Mae cut herself, Pa got a snakebite, yet all of them survived. They also noticed that year after year, they never seemed to age.
Finally, they suspected that the spring water had made them immortal, and Angus Tuck set out to prove it. Mae explains:

"He said he had to be sure, once and for all. He took his shotgun and he pointed it at hisself the best way he could, and before we could stop him, he pulled the trigger." There was a long pause. Mae's fingers, laced together in her lap, twisted with the tension of remembering. At last she said, "The shot knocked him down. Went into his heart. It had to, the way he aimed. And right on through him. It scarcely even left a mark. Just like—you know—like you shot a bullet through water. And he was just the same as if he'd never done it" (Babbitt 40).