Nothing wrong with using rancid bacon fat grease if you don't mind the smell. Put some of the bacon fat in a pot and melt some bees wax or paraffin wax mixed with the fat and throw in some cologne to mask the rancid smell if the bacon fat is rancid. Or use scented candle wax. The beeswax, candlewax or paraffin wax melted together with the bacon fat, will stiffen the bacon fat some, but still be pliable enough to use and keep the bacon fat from running out of your cylinders on a hot day. Less messy too with it being a little stiffer than crisco by virtue of the added wax.
I wouldn't worry too much about the salt in the bacon fat corroding your revolver. The corrosive salts in the mercury fulminate residue from your percussion caps are more corrosive than bacon fat salts. And you aren't going to leave your BP revolver loaded with salty bacon fat/beeswax lube laying around without planning on shooting it immediately and then immediately cleaning it. Chicken fat, pork fat, beef fat, bear fat, even motor oil and just about any kind of fat/oil melted and mixed in with beeswax will work.
You could get a lot of chamber lube out of rancid bacon fat melted together and mixed with a couple of scented candles wax or other wax. Give it a try. Melt some wax in with the grease and then let it cool. Test it to see how pliable it is. Then melt more or less wax into the mix as needed. Should work just fine.
Also, since you said you wanted to know how old timers did things, get yourself a set of the Foxfire books. Especially volume #5 which is about making black powder and muzzle loaders from scratch and loading and firing, like the old timers did.
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