Seems pretty definitive to me. People carried spare cylinders as a quick reload.
There are a number of historical references and even artifacts in this thread. Why would they need to repeatedly document spare cylinders beyond the ads for sale and these stories? I would suspect most considered it "common sense" and self-evident.
Experimentation start approximately 1866. Colt tried a few different methods prior to the S&W bored through patent expired.
Actually, there are references in this thread to people often possessing both types of cylinders, especially for the Remingtons, and especially on the frontier. Sometime int he early days of cartridges, they were hard to obtain, particularly in remote areas and the small towns of the west. However, lead and black powder were nearly always available, having been part of the supply chain for decades. So, if you were unable to obtain cartridges for your revolver, you went to your C&B cylinder, rather than just having a paperweight on your hip, until such time as you located ammo.
Also, the vast majority of Civil War soldiers were not issued revolvers. A simple look at the number of long guns vs the number of revolvers issued reveals that. Revolvers were pretty much confined to cavalry and officers, while the bulk of the forces, infantry afoot, never were issued pistols, although some more wealthy individuals may have sprung for their own, but then they would have likely been on their own for ammo as well and would likely have chosen the smaller pistols you refer to.
