Thanks Harry,
I have been doing lots of research. I like this evolution in cartridge design, while short lived it was the latest and greatest in its day. And as I mentioned I have always just wanted one.I will post some pictures of the pinfire shotgun in another thread. It is a nice gun and I'll figure out the shells.
While pricey, I ordered 2 of these to see if they will work and then I will likely order 18 more:
http://www.hlebooks.com/pinfire/cal16-01.htm
I contacted Rocky Mountain Cartridge and they don't make Pinfire shotshells any more. Though they are making some brass 12b shotshells for me.
On the henrykrank website I didn't see and 12 gauge shells just 12mm , they do have a lot of neat stuff on there.
I will check out that article you mentioned. I have run across a few people who were modifying modern primers and plastic shotshells and getting them to work well.