My opinion, if you don't have a supply of powder and primers you're SOL. In any case scrounge every piece of brass you can find. Get out to the range and mine the banks for bullets to melt down for casting. Old timers may remember when people used spent rimfire cases as jackets - that equipment is still out there if you look. At the least you can keep your handguns and lever guns (and a few reduced loads in the bolt guns) well fed. Yes, it takes a bit more maintenance but you can weather this storm.