I have both a Colt Walker and 1860 Army with the same problem. Using FFg splits the caps. Pyrodex DESTROYS the caps. I have been using CCI #11s. They are so mangled after firing I have difficulty removing them so that I may take the next shot. I have installed after market nipples with a much smaller flash hole that was supposed to reduce the back pressure, but that did not work. Anyone have a solution? Does anyone make a "heavy duty" cap?