I thought I would elaborate a little on the Dayton Gun Headquarters, the owner and president was Joseph Hanen. They were modifying Ruger 10/22's in the mid to late 1960's, at the same time the Dayton S&W guns were produced. Hanen was apparently a firearms expert and was both a collector and shooter. He had an elderly woman in has employ who built all of the "Hanen Sportsman" 10/22 rifles. All of my info comes from Workman's book on 10/22's which has a small section on dayton gun headquarters, but makes no mention of other special guns produced for Dayton.