Try Cornell Publications.
No definitive sn data published.
Cornell Publications might have a book with that information.
No detalied sn data published Other answer: The No.6 was made between 1896 and 1899
Sorry- H&A went out of business in 1916, and there are very few production records for the company.
1887.
if the top of the barrel reads Hopkins and Allen MANUFACTURING CO, it was made before 1896. If it reads Hopkins and Allen ARMS CO, it was made after 1898.....
Hopkins & Allen ended business in 1916, and there are very few points in the database. Sorry-
idddkkk
Made 1902-1914
Hopkins and Allen purchased Forehand Arms in 1902, so sometime between then and 1915 when the company closed.
Hopkins & Allen Arms Co. Fifty Years of Gunmaking 1867 - 1917 by Joseph T. Vorisek is about the best book on H&A.
1870-1910 or so