Western game, reloading revolvers is a test based on the maximum number of rounds the gun can hold. With a six-shooter, you roll a 1d6 + a relevant skill.
Also, wanted to combine this with a weird west setting based on alternative history: Napoleon won and conquered most of Europe, now also pushing into the Americas. The Aztec empire never collapsed, it got stronger instead and extends its influence into the plains. And Japan did its empire thing early and now settling on the West Coast.