Thank you, everyone. Good information and a few laughs.
I don't actually need the gun to survive the fire -- my heroine has a second revolver not in the house. I just didn't want her to write the gun off as a loss if the fire wouldn't ruin it or salvage it if that wasn't probable. I'll just let the fire do its thing. Although, I like the hidey-hole idea and might use that in another story.
As for the flask of powder, I was hoping for dramatic firework-like pyrotechnics, but I guess that's a little too "hollywood."
Rachen – Good luck back at you.