John Bivins, in the Acknowledgments of his book "Long Rifles of North Carolina," gives acknowledgement to "Foremost of those who helped is Dr. R. H. Mackintosh of Rock Hill, South Carolina, who began pioneering research in the field of Carolina rifles some years ago and who is continuing this study in depth." I would assume that Bivins consulted with Dr. Mackintosh at some point, so, by default, could not some of that research have been reflected in Bivins' book?
In William Ivey's book there was at least one "Owner" reference to the "Mackintosh Collection" (see rifle #154.)
Others know much more. Just my two cents.
Caw.