A sound-suppressed .22lr, takedown autoloader, with a retractable stock and 7" barrel, with a see thru mount, 2x7 scope and dayglo paint on the iron sights (something like the Marlin Papoose) makes more sense to me. You're not going to have the saltpeter and sulphur for making black powder. "Corning" same, (needed to make it burn properly in a firearm) is very dangerous. You need so much blackpowder per shot, it's so corrosive, such a pita to clean up after each shot, wow! It's also just a single-shot, short-ranged, noisy,lots of flash at night, wont pierce concealed armor and it draws moisture.

If you need to forage, so will millions of other people and too many of them will shoot you on sight, post shtf. It only takes one person, and one .177 pellet, buckshot pellet, .22lr bullet to outright kill you, or give you such an infection that you die of it. So, realistically you dont want such arms for a survival sort of scenario. If it's not shtf, your normal ccw pistol and a rental satellite phone will do far more for you than any sort of longarm, and it's a lot handier to carry, too!