Thank you kindly for the effort and information you have compiled!
Very relevant in today's political climate as I'm sure many folks have a stockpile of small rifle primers which will, in a pinch, substitute in small pistol loads.
According to some internet reports, which I have no way to verify, but perhaps it would be a good question for John, in some instances, Magnum small pistol primers and normal small rifle primers have the exact same amount of priming compound.
Again, this are claims by unverified internet sources, and I'd feel more comfortable from someone whom I know had reputable industry connections, so take if for what it's worth.