The Lonely Gun — Gordon D. Shirreffs

The Conquistadors had called it the Devil's Highway. It was the highest, driest, meanest desert in northern Mexico, and Case Hardesty had to cross it on foot or die. Behind him were the outlaws he'd taken for $20,000, and behind them the lawmen who had sworn death to them all. In one hand he held a Winchester, and in the other a salt sack stuffed with enough bills to buy a ranch in Sonora-if he made it. Or a grave, if he didn't.