License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Nicolas Noël Boutet. Double-Barreled Flintlock Shotgun with Exchangeable Percussion Locks and Barrels, ca. 1818–20; exchangeable percussion locks and barrels, dated 1860. The Metropolitan Museum of Art.