In the classic SHTF scenario..in my opinion, you aren't gaining anything because you are still relying on "store bought" ignition. So just cut to the chase and get yourself a decent quality flintlock, preferably a smoothbore, learn how to shoot and maintain it. In spite of the schidt Hollywood peddles, North America was tamed with smoothbore trade guns and fowling pieces.
I'm looking for a cached, do-it-all gun. By chance I have lots of 209s and blackpowder, so there is that. I have 2 other ML rifles, but the breakopen is far more versatile.