Hey Bruce you are partially correct but on a peacemaker it was a single action revolver so there is no need to leave an empty chamber, you have to manually $@+# the hammer before it can be fired so as long a you dont ride around cocked your fine its not going to fire. Its a built in safety.

An average person has a 2 dex so they can load 2 bullets a round which would be like bruce said take about 3 rounds to load 6 bullets but a character in a game is hardly ever average so its conceivable that a character with a 5 or 6 dex could damn near totally load or load it all but one bullet in a single round. If they are on horseback or other tough situation to handle small bullets and a gun have them make a difficult dex roll per bullet

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"The gun katas. Through analysis of thousands of recorded
gunfights, the Cleric has determined that the geometric
distribution of antagonists in any gun battle is a statistically
predictable element. The gun kata treats the gun as a total weapon,
each fluid position representing a maximum kill zone, inflicting
maximum damage on the maximum number of opponents while keeping the
defender clear of the statistically traditional trajectories of
return fire. By the rote mastery of this art, your firing
efficiency will rise by no less than 120%. The difference of a 63%
increase to lethal proficiency makes the master of the gun katas an
adversary not to be taken lightly." - Dupont, Equilibrium