Primers are the last item on my list of concerns.
I have used Winchester 209s in both plastic and paper shells. There are lessons to be learned. Primers were not the problem. Basically, blackpowder is hard on stuff. Paper hulls burn through in a load or two. Plastic, on the other hand, doesn't burn through - it just melts. Don't use anything plastic around blackpowder.
The tougher element is wads and lubes. I'm still trying stuff. There are a lot of variables that include the span of time between loading and shooting, and how much shooting is done and over how many hours. Do a web search, find some homemade concoction you think you can whip up in or around the house without getting thrown out, and just wade in.
Oh, primers. I forgot the thread. Nowadays I use some righteous brass hulls powered by pistol primers. Works great.
