In Ray Bradbury's short story "The Sound of Thunder", what happens to Eckels at the end of the story?

Although Bradbury does not specifically state what happens to Eckles, we can assume that Eckles is killed by Travis.  Discovering that Eckles has indeed brought back something from the future and the course of history has been changed the end of the story has Eckles on his knees with his eyes closed and hears Travis move his rifle, take off the safety and then a sound of thunder, or as I understand it to mean, the firing of the gun.