Don- for many years, Elmer Keith told of the "Proper" method of loading the Cap and Ball revolvers.
_ Full charge of powder, waxed wad- (felt preferred)oversized ball or bullet. There is/was/never intenteded to be any grease or whatever placed over the ball in the chamber mouths. Elmer tired it as that was the favourite method in print in the 70's & he reported decreased accuracy. I do believe his load for the 1860 Army was 30gr. 3F, but it could have been 2F - I don't remember. With oversized balls, .451, .545 or .457, which ever the revolver required, along with the waxed wad prevented chain fires FROM THAT END - according to him.
: Most chain fires were from the nipple end of things, and the recessed nipple seat was Sam Colt's patent to prevent that from happening, when using, proper sized caps, of course. Many revolvers of the period didn't have that 'protection for the nipple, but then, many others got around the patent in various ways. One even had individual spring clips to hold the cap in place, one for every nipple.