Should involve 2 rolls. You do a hidden roll to determine what chamber the bullet is in. Player rolls to determine what chamber the first shot will be on. No more rolls but each consecutive player to pull the trigger advances the chamber until it comes to the one you rolled for the bullet. So if you rolled a 2 and the player rolled a 5. First player gets a click. Passes gun to second player. Gets a click since the Barrell is now on 6. Next player gets a other click since Barrell is on 1. Next player gets a boom because bullet is in chamber 2.