The Angel & Her Gun — Kate Copeseeley

Samora is a gunslinger in the Wild West, but she doesn't just carry a gun. She also carries the cross ring that designates her as an angelic agent, sent from God himself to battle over mortal souls on earth with the demons who seek to win their ages long battle.
She has two problems: her propensity for getting screwed over by conniving mortals and her love for Gideon -a fallen angel on the wrong side of the law.

This is a short story, about 25 pages or 8,000 words.