I knew Paul Marquart reasonably well in the mid-70s. He and Atkinson had a partners for many years until a rifle blow-up accident took a few of Marquart's fingers, ending the partnership. As I remember Atkinson made the barrels while Marquart fitted them (?).
Paul Marquart was probably best know for outside case neck reamers that may still be available. Great guy!
I met him giving a tour of the GS Dept. at TSJC about 1977 not knowing he was a graduate, or his credentials until the tour was competed.