Space magic. Your right. In real life they would be non functional. I'm guessing that the designs were made more for looks than anything. If you wanted to get real technical in a futuristic space magic setting...then here is a quasi explanation. Using space magic...the light of the traveler...glimmer is used as ammunition. This matter, according to the grimoire can be changed and manipulated as needed/desired. All a gun would "need" is a place to store glimmer, a converting mechanism, and an exit point. The cylinder for hand cannons as well as the hammer would be added as a mere aesthetic, to a former era. Perfect example is The Last Word. It could explain how your able to fit 13 rounds in a tiny hand cannon cylinder. Hawkmoon and so fourth. Just my thoughts...about the far advanced sci fi video game guns that use space magic. Lol. No hate. Edit. Since you seem to know your guns. Is there a reason for having the revolver fire the bottom round versus the top? I saw the vid you put up of the Italian 357. It was neat, and was wondering it say had less recoil because there would be more weight on top of the barrel? Real question, I'm not much of a gun guy.