1960 - Stackpole Press and associates
As the tag to his Preface, Kauffman references the Capt. Dillin, 1924 work but says this volume is the result of "a great deal of research ...done on the subject of muzzleloading rifles made in America. since Dillin's work. And this book is limited to those made in Pennsylvania. He anticipated doing another on Ohio-Kentucky and a third on Plains Rifles ... but I don't find either of those ever made it. Kauffman, however, has written extensively on early metal work - copper, iron and pewter. The man is good and knowledgeable.
Lots more information and pictures than in the Dillin book ... but they are both very respectable and necessary if you want to do any research on early American long guns.
And I have four (4) copies ... three different covers (and the "duplicate" cover ... Book 2 has a dust jacket and is the same cloth cover as book 1. So I have listed them separately ... even though they are the same book at the same price. The pic of the tan/brown cloth binding is the actual cover under the dust jacket of book 4