No, I didn't think there was, just sometimes we ask rhetorical questions. Something to stir the old thought machine.

Here is a home-made tester page. I thought it was kind of ingenuous.
http://www.castingstuff.com/pr...esting_reference.htm

I have several calls into primer manufacturers and am awaiting their calls.

I did call one powder manufacturer and they stated that they don't have anything to do with primers other than make a solution for making primers. Of course they only sell that to the industry!
At any rate, they said that the only difference is their "brisance" and cup hardness. Of course size is a factor on the "large" side of things.

Cup hardness translates to the resistance of the primer to extrude under high pressure and the striking force required to ignite it.

When I have some verifiable information, i will post it.

Thanks for stirring this discussion.