Good start to a gritty western. I like the imagery and the mood you set. Two suggestions:

Pausing at a hand painted wooden sign, “Calamity” Sam Townsend lifted his hat and wiped some of the sweat off his forehead with his sleeve.

The phrasing here was a little awkward and I thought at first that “Calamity” was the name of the town and not the protagonist. Perhaps you could invert the sentence?

That was enough to bring make his lips twitch into a smile.

There seems to be an extra word or two here.

I particularly liked the phrase “A tired shadow skulked into town”.

I also thought the town name was Calamity, so I’ll support BARomero’s comment. I thought the middle paragraph was the strongest, with the start being a little adjective-heavy. Still, good, gritty, Western fun. Lots of possibilities here.

Changes noted and fixed, more or less.

I liked it! Very good atmosphere!