Apparently, there is some sort of gene that is associated with both left-handedness and action movie (including Westerns) characters. Far more folks in action movies seem to shoot with their left hand than population averages would suggest. Either actors are more likely to be right-brain types (and thus are left-handed) OR the proclivity to use a gun or a sword is related to the tendency to be left-handed. OR there is a strategic advantage to use the left hand, allowing the lefties to survive gun battles and sword duels.
More study is required, of course. Starting with this egregious 1980s video directed by James Cameron and starring Bill Paxton (with Hurt Locker director Kate Bigelow making an appearance).
HT to retweet by Doc Jensen