This is an Ithaca Model 37 riot gun with trench handguard attachment and "USSF" stamped on the lower left of the receiver. The left side of the barrel is roll-stamped with the two-line Ithaca legend followed by "CYL" and a "P" proofmark, with a second "P" stamped on the left side of the receiver near the barrel. The barrel is fitted with a World War II pattern six-hole heat shield with bayonet adapter. The Ithaca "Roto-Forged" logos are stamped on the right of the barrel and receiver. The pistol grip stock has impressed checkering on either side of the wrist, and is fitted with an Ithaca branded black plastic buttplate. "SP-30-06" stamped on the right of the bayonet adapter. A nearly identical Ithaca Model 37 trench gun is illustrated on page 267 of "The Worlds Fighting Shotguns" by Thomas F. Swearengen with the caption, "Right side of an Ithaca Model 37 reportedly made for Army Special Forces". Rock Island Auction previously sold an identical example exactly 400 serial numbers off this one (serial number 371369484, auction 71 lot 1611).