Going back to the 1850's Government and State orders for Colt's pistols usually included a few thousand combustible cartridges, percussion caps, screwdrivers, conewrenches and bullet moulds. The bullet moulds were quickly discarded by the troops issued them, because they preferred using the cartridges.
The unpopularity of casting round or conical balls was such that it ultimately led to the government no longer ordering them by the end of 1863.
Concerning chain fires; your brother was using improper sized bullets or the wrong caps. The original Colt instructions for loading these psitols advised against using wads and makes no mention of grease.
They do urge the user to use soft lead and the correct size ball, for a tight fit.
When, in may of 1860 a board of officers tested the Colt new model army pistol for possible army adoption they filled the chambers to capacity and even sprinkled loose powder around the cones and balls and yet did not succeed in achieving a chain fire. They also tried different cartridges without injury to the firearm.
Needless to say, they were very enthusiastic about this new, light army size pistol.
The fact that these weapons were procured by the hundreds of thousands and were in great demand by both sides troughout the war proves their effectiveness.
Many examples show hard use but survived the war and the frontier, even early production ones, suggesting that quality percussion revolvers such as Remingtons and Colts were far more reliable than people give them credit for.
Sources: The history of the colt revolver and other arms made by the colt patent fire arms mfco 1836-1940 by Frank A. Belden and Charles T. Haven
The Colt Model 1860 army revolver by Charles W. Pate