Daring Pony Express Riders (True Tales of the Wild West) by Jeff Savage

Pony Bob had traveled more than a hundred miles. Exhausted, he still kept moving. As a Pony Express rider, he had mail to deliver. Suddenly, he heard yelling. A group of Paiute warriors were chasing him! Bullets whizzed past him. One bullet struck his shoulder; another grazed his cheek