Vengeance Trail

Eleven year old Zebulun Ball watched as six Missouri border ruffians murdered his family, burned their Kansas farm, and left him for dead. A nearby family rescued him and raised him as their own. As he grew, there was one thought in his mind: Vengeance. He learned to use a gun and use it perhaps too well. His adoptive father talked him out of vengeance, but justice was another matter. Even when he wasn't looking for the men who murdered his parents, he seemed fated to meet them. He enacts justice in a blaze of gunfire. Finally, wanting to get away from the violence, he joins a cattle herd and works his way to Montana Territory, where he founds a ranch of his own. However, fate has other things in mind and justice will not be denied.

From the book:
Zeb walked down the boardwalk, simply looking at the shops and people as he went. He was amazed that there could be so many people around with seemingly nothing much to do. As he passed a saloon, suddenly a couple of men burst through the door and out onto the board walk. One of the drunken men ran into him as he barged out, almost knocking him off of the boardwalk. The man growled, You dare to run into me, farm boy?

Shock ran through Zeb. Realization of who the man was hit him at the same moment he realized the man was drawing a gun. Someone grabbed his right arm at the same moment. He was going to be murdered! He reached with his left hand and pulled his pistol, firing two shots that sounded as one. The man's pistol shot exploded into the wood at his feet. As the man was falling, he shot the man holding his arm, who collapsed with a moan. Dead at his feet, with his blood soaking the boardwalk, was big Dick Chaney, a man he saw shooting his mother.