Don, I'm curious. What possible problems could you have with a flat breech? Patents have all kinds of issues, just because of restrictions, and passages. Hard to clean, etc.
I guess I'm just talking flint locks though .
Smallpatch,
I suppose I've been lucky with my T/C patent breeched rifles. Ever since getting the first one 40 yrs ago, I've been doing just like Daryl said..pull the barrel, put one end in a container of water and flush the whole thing out end-to-end. Easy, and never had an ignition problem over all that time, and a LOT of shooting.
OTOH: My first experience with a flat breech rifle was with a Jack Garner flintlock.
I will admit at this point in the conversation that the problems were most definitely the result of my own ignorance, which has been addressed over the years. I'm much better now. In short, I was wiping between shots with a jag/patch combination that was a bit too large. As a result, I was pushing everything that was in the barrel down the bore to rest on the breechface before pouring in the next powder charge. That's the process which had worked on my T/C's, and there wasn't anyone around to tell me any better, so off I went..and it wasn't long before I was having all kinds of ignition "issues".
Other folks experience may differ...this has been mine. Always willing to learn.