This is an extremely rare WWII military trench shotgun that was manufactured by the Ithaca Gun Company for the US Army, circa 1943/44. This is probably the rarest of the WWII US Army trench shotguns and probably only second to the rarest of all the trench shotguns, the WWI Remington Model 10 trench shotgun. There was only a very small number of original Ithaca trench shotguns manufactured during WWII, all in a documented serial number range of "57820" to "61450", with this example being numbered "57972". There was an additional Ithaca contract let during Vietnam, however they were produced in a considerably higher serial number range consistent with the 1962-69 commercial shotgun production. These WWII Ithaca shotguns were originally manufacture for use as military guard guns and eventually were used in the Far East as effective weapons during the jungle fighting. They had an all blued metal finish with an Ithaca factory commercial varnish on the pump handle and buttstock. The barrels were fitted with the early, short, 6 hole sheet metal handguard which had a bail sling swivel on the bayonet lug and standard sling swivel on the lower underside toe area of the buttstock. These original Ithaca trench shotguns can only be identified by the serial number range and the Ordnance inspection proofs found on the left side of the shotgun. In this example that consists of a "P" firing proof, followed by the small U.S. Ordnance Shell and Flame proof, followed by "RLB" which are the initials for the U.S. Ordnance inspector Lt. Col Roy Bowlin from the Rochester NY district. It is correctly serial numbered on the right front edge of the receiver and right, rear underside of the barrel (both matching). The two line Ithaca factory barrel markings are clearly visible on the left side behind the heat shield. It has a single brass bead sight on the bayonet adaptor. The barrel has the 12 ga-2 3/4 inch chamber markings. The receiver is correctly smooth on the sides with no hunting scenes. It has the earlier factory varnished walnut stock with checkering on the side of the pistol grip and a ribbed pump handle. The buttstock correctly does not come with any cartouches of proofs. It comes with rare "L&C/1942" marked leather sling.