Disclaimer

If you play this game with an actual revolver you are beyond stupid. Do not do that.

The Actual Resolution System

Get a revolver's simulator, or a cap gun (in which case please don't put it next to your ear) or the equivalent, then load 1 bullet in. Then spin the barrel. Every time a character does an action that risks death, pull the trigger once. If the gun fires, the character dies. Every time a character does an action that puts them and others at risk, insert an extra bullet (max 5) and spin. Every time a character does an action that protects them from danger, remove one bullet (min 1 may be left) and spin the barrel.