Do all cowboys kill ? or do some have a no kill rule like superheroes ?

During the time of Westerns, it was okay to carry a gun in public. And it was okay to kill to settle things. Their ways of life was very different from ours. But since almost every one carried guns, there probably wasn't many violence due to the fact that everyone was scare of everyone. I remember hearing that records shows that there wasn't as many crimes back than as it is today. So not all cowboys got into a gun fight because they were afraid to die themselves. The type of guns they used back in those days were Revolvers and I'm sure people during those time has learned how to shot those guys very fast. Just look at this video of how fast Bob Munden can shoot his revolver.

https://www.youtube.com/watch?v=jAOPp_4QHFo

When you can shoot that fast, I doubt a lot of people is going to want to mess with you. So I'm going to guess there were no kill rules because it was better to kill your opponent than to let them live and come back to kill you later.