Dave's mother allows him to buy the gun on the condition that he takes it straight home to her. However, Dave doesn't go straight home but stays out late, returning only when he thinks his mother will be in bed. When he gets home he puts the gun beneath his pillow. When his mother tiptoes into his room later that night and asks for the gun, Dave "plays possum," which probably means that he pretends to be asleep. When that doesn't work, he tells her that "the gun (is) hidden outdoors," and that he will "bring it to her in the morning." This excuse does seem to work, and his mother goes to bed, leaving Dave to examine the gun.
The next morning Dave takes the gun from under the pillow and holds it up to the "gray light of dawn," testing its weight. The fact that it is so early implies that he couldn't sleep for excitement. He seems to have woken up early especially to hold the gun, and he feels "a sense of power" when he does. After holding the gun for a little while, he takes out the cartridges and feels them, before putting them back in. He wants to hold, and feel in his hands, every part of the gun. He then proceeds to wrap the gun in "a long strip of old flannel," which he uses to tie the gun, "still loaded," to his thigh. Skipping breakfast, Dave then heads out to Jim Hawkins's plantation.