The included copy of a Winchester factory letter dated December 28th, 2016 states, "Serial number applied on April 29, 1918." This World War I era Winchester Model 1897 trench shotgun falls into the approximate known serial range of E613000-E705000. The Winchester 1897 was one of John Browning's many contributions to American sporting and combat arms, and in both the "trench" and "riot" configurations performed fine service for military and law enforcement users, seeing action as early as 1899 in the Philippines, and earning particular fame in World War I and World War II for its potent close range firepower. Features a six-hole handguard/bayonet adapter with "PAT.JAN.15&MAR.19.1918" marked on the left. The barrel protrudes 1/2 inch ahead of the bayonet adapter, which is considered correct for a World War I era Winchester 1897 trench shotgun. Receiver and cylinder choke marked barrel both stamped with a circled Winchester "WP" proof at the breech. The slide bar has the model and trademark information. Grooved forearm and smooth pistol grip stock with a Winchester branded checkered hard rubber buttplate. Length of pull is 13 3/4 inches. Includes M1907 brown leather sling. Reference page 50 of Bruce Canfield's book "Complete Guide to United States Military Combat Shotguns" for information on World War I era Winchester Model 1897 trench shotguns. Includes Winchester M1917 bayonet with later production scabbard.