I would be interested in knowing 12brd's method of using the #57 primers in the 209 pocket. To use the 209 primer in a 57 pocket on the old paper shells simply required swaging the pocket up. I knew one man years ago who simply bought the 209 size & primed all his shells, irregardless of brand, with them. His press pushed them in & apparently he never had a problem with this method.
To do it the other way around requires either Reducing the pocket or bushing up the primer.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra