The scene where Glenn Corbett refrains from shooting Patrick Wayne, and instead chooses a "fair draw," resulting in his own death, seemed very unrealistic, and a bad idea, at the very least.
Yeah, it proved to be a bad idea, but not unrealistic. As Breed (Glenn Corbett) wanted to try out his draw against someone who he knew was good, but not as good as him, or so he thought. And shooting Patrick Wayne's character would not have allowed Breed to try his draw against, again I say, someone he knew had a fast draw, but not as fast as him, or so he thought. But, in the end, it did prove a bad idea, because Breed wasn't as fast as he thought he was, at least against Wayne's character.
Patrick Wayne's character also has a spring action holster, and Corbett's character doesn't know that. The scene makes a point...technology has made a fast draw irrelevant.
What makes you think he had a spring action holster? The only time this is ever said (not implied) is when Michael says, "You know what I think? A spring. A spring at the bottom of the holster". That doesn't mean he actually had one.
"Parting is all we know of Heaven... And all we need of hell." - Beast, 90s X-Men Cartoon