My picks for the worst costumes in a mainstream Western. 90% of the clothing in 90% of Westerns is wrong but there's wrong and then there's wrong. My first pick is Michael Parks' tourist sombrero in Django Unchained, complete with plastic string adjustor:

He's definitely not helped by his Kohl's button-up shirt or John Jarratt's fucking T-shirt. Pro-tip: shirts were pullovers throughout the 19th century. Full button-downs are more 20th century, and T-shirts didn't exist.

Second pick: Bruce Dern's Jean jacket in Posse. This was still the Victorian Era and jeans were known as "overalls" because they covered "proper clothing" (what we think of as overalls were known as bib overalls). No one had jean jackets:

Sam Worthington's hat in The Keeping Room. I don't know when these weird leather hats came over here from Australia but it was probably just short of a century after the Civil War. Sam looks like the type of country singer I would avoid: