Oswald was hungry:
This is what will happen. I will write what happens when Lee Harvey Oswald decided to grab a hot dog, and how that foiled his plans to kill Kennedy. You guys get to make up the rest.
Friday, November 22, 1963:
12:15 pm: Fifteen minutes before Oswald kills Kennedy in our timeline:
Oswald is in the Texas book depository, with his rifle wrapped up. He is not in his position yet, but rather on the first floor talking to a friend.
Oswald says he is feeling hungry. He notices his friend is having a chili dog for lunch. He then notices his friend has two chili dogs. Oswald asks if he can have one of them. His friend agrees.
12:25 pm: Oswald goes up to his position, waiting for the president to come. Since he has five minutes to kill, he props his rifle up on its butt-stock and leans the barrel against his chest. He decides to take a bite of the chili dog. He takes a mean and messy bite, and a whole bunch of chili falls down the barrel of the gun. The gun jams, but Oswald is unaware.
Kennedy goes by in his car. Oswald pulls the trigger, and nothing happens. He keeps trying for about 15 seconds. Eventually someone notices him and he is reported and arrested.
You guys decide what is next.