I wound up fighting fire the first time I killed a deer with an old CVA kentucky, years ago. I was using Crisco for patch lube. Since then I have tried a lot of different lubes for summertime shooting here in California ( our deer season starts the second Sat. of August). The one that has never showed any signs of smoldering is a venison tallow base, with mink oil, or neatsfoot oil, even bear oil, or something similar, just to keep it from being to stiff. venison tallow, or mutton tallow, has a very high flash point, and is nearly impossible to ignite from momentary contact with flame, such as in your barrel.
Hungry Horse