Is there a reason in the Old West that people didn't wear any body armor in shootouts and duels?
What about it?
It would seem smart to at least put an iron plate under your shirt to protect your centre mass.
I'm asking as an Aussie. Back then around the same time, we had Ned Kelly, a legendary outlaw who dressed in a suit of 1/4 inch iron armor, which made him effectively bulletproof even to the rifles of the era, during police shootouts.