I often read that Civil War cavalrymen carried spare cylinders and reloaded with them in the saddle. Since I picked up a Remington New Army reproduction and actually tried swapping cylinders, I have come to doubt that. It's a two-handed operation that requires manipulation of the hammer position, cylinder, cylinder pin and loading lever. I can manage it easily enough at the range with both feet on the ground, but can't picture doing it on horseback in the middle of a gunfight. Carrying capped and loaded cylinders seems like a pretty risky proposition and uncapped cylinders aren't going to be much help. Clint Eastwood seems to manage it easily enough, but I wouldn't try it. A second (or third) loaded revolver seems like a better idea.