The book The New York State Firearms Trade by Holman J. Swinney, compiled by Tom Rowe, Volume I (it's a five volume set) has so much information on the Caswell family gunsmiths, that I wouldn't know where to start. Pages 316 through 356 are all on the Caswell gunsmiths, and there were many, all part of the same family. John M. Caswell was born in Connecticut on Sept. 2, 1777, probably in Woodstock. Swinney list him in Albany, New York 1814-16; Troy, New York 1819; and Lansingburgh, New York 1820 -50 or later. He died September 4th, 1857. J. M. Caswell's shop was, during the 1820's and 1830's, the most important gunsmith shop in Upstate New York. It steadily employed 20 to 25 men, and was producing between twenty and thirty-six rifles per week in 1833. There was also a J. M. Caswell, Jr., who worked at the trade as well. Information on him is scant, but he was born April 9, 1803 and died June 25, 1880 in Pontiac, Michigan. This information barely scratches the surface of what the book contains. There are many pictures of Caswell firearms, all of superior quality.