Checking Firearms Shop... ooh, a breech-loading revolver using .22 rimfire cartridges. 10 seconds for emptying the cylinder, then 5 seconds per shell for reloading. I guess having to remove the cylinder for reloading was somewhat time-consuming, but at least it's not a cap-and-ball.

Hm, I see this listed as a 7-shot in most places, a 5-shot in some...

OK, the overall situation is a little more complex than I first thought. There must have been a good reason to choose cap-and-ball inspite of the S&W cartridge revolvers being available. Was it a matter of reliability? Stopping power of the larger calibers?