Does this sort of thing really happen?

I seriously doubt it. If you shoot you probably know that even at those relatively close ranges accuracy problems would kill it quick. There would be enough injuries from it combined with how sensational a news story it would be I think you would hear about it even in foriegn countries. YouTube and all that.

I could probably hit the vest fairly consistently aiming carefully, but with someone's life on the line I wouldn't want to try it, more importantly I wouldn't trust someone else firing back. That's without factoring people with adrenalin firing without really aiming, there would be a ton of leg and groin wounds.

Also even the movie mentioned how the vests lose their cohesiveness after getting hit even once. That one fight he had with the big guy I would imagine would have had a very high chance of a round getting through.

An observation I had as an aside. Most of those draw styles would probably be counterproductive, one would be the clear fastest and the one everyone used. And no way in hell would Mickey Rourke's character pull out of his belt, at least with the site still on the end of the barrel. It would catch every time.

No, it does not happen in reality, at least not even remotely in that format.

It is true that the concept of a "duel" is a major part of European culture (Pushkin comes to mind immediately). But this movie is essentially an American attempt to re-create that concept in a different time and different setting, based on incomplete and woefully misunderstood information. It is what's often referred to as "cargo cult". It's like making an exact replica of a radio antenna out of bamboo sticks and expecting it to work.

It does happen in real life, but no where near as much as the movie makes it appear to be.

And I imagine in real life it's mostly slave owners forcing their slaves to shoot each other.

3rd world countries are messed up. They get off on this kind of stuff.