Hi :
I wonder if the book you mention would answer my quiry below /

New to the sight & I wasn't sure where to post this but I was wondering
if someone could enlighten me to some of the different Crown over Initial
Proof Marks that I've seen seen over the years. I 've seen Crown N stampings
which I believe means modern gunpowder not blackpowder. Correct me if I'm
wrong.

What does Crown over U , & Crown over R denote ? Could someone educate me on some
of the more common proof marks ?
Thanks;

Mike