I think percussion loading was just slightly faster than flintlock, but much more versatile in various ways. Powder from a powder horn can get wet, spill, or blow away in a wind while one is trying to load it. As for loading, one would put some black powder down the gun barrel, then a wad, then a lead ball, then another wad...all done by using a ramrod to push them down...then mount a percussion cap on the little round holder where the firing pan used to be on the flintlock, then aim and shoot. The percussion cap held a tiny charge which would go off on impact like a cap in a cap gun, thus setting off the black powder in the main firing chamber and shooting the bullet.

Early pistols were one shot flintlocks, or two shot if they had two barrels, or three shot if they had three barrels, etc...The same basic arrangement followed with percussion cap pistols. After the invention of modern cartridges it was easy to have a fast-loading six-shooter with a rotating barrel. I think there were percussion six-shooters with rotating barrels too, and 6 percussion caps. It took a fair bit longer to load them, needless to say. In the heat of close battle you would shoot off whatever rounds you had, then resort to a saber or edged weapon or whatever else came to hand...and use the gun itself as a small club.