THE NEW YORK STATE FIREARMS TRADE,, by H. J. Swinney/Tom Rowe, has 22 pages devoted to John M. Caswell. It states that the most important gunsmith shop in Upstate New York, during the 1820' & 1830's, was that of John M. Caswell, in Lansingburgh. It steadily employed 20 to 25 men, and produced, in 1833, "from twenty-five to thirty rifles...and sometimes thirty-six" per week. Caswell was previously in Albany, 1814-1816, and probably in Troy, around 1819. John M. Caswell was born in Connecticut in 1777, the son of Thomas Caswell, also a gunsmith. There were other family members, including at least one brother, Solomon Caswell, and two nephews, Hiram and Eli, who were also involved in the business. John M. Caswell died on Sept. 4, 1857. There was also a son, John M. Caswell, Jr., who was for a time involved in the business, but there is little information on him. The New York book contains pictures of a number of J. M. Caswell firearms of all types, including several pairs of pistols.