A martial variant of a John Browning designed sport gun, the 520 trench shotgun was originally developed in response to a World War I request for new fighting shotguns for the American Expeditionary Force. It made a strong impression on the evaluators but did not make it into the field before the armistice was signed. Seeing potential for the gun on the police market, Stevens kept production going until 1932, and at the outbreak of World War II, the U.S. government bought every 520 that was still in the warehouse. Checked back into the arsenals at the end of the war, many were sent back into the field for the Korean War and Vietnam. Fitted with a reproduction bayonet lug adapter and ventilated handguard. The right side of the barrel has the three-line Stevens Company address. The left side has the two-line gauge markings "PROOF TESTED-12 GAUGE/-2 3/4 INCH CHAMBER-". Choke gauges at cylinder. The left side of the receiver is stamped "MOD. 520-30", the correct "P/Ordnance Bomb" proofs are stamped on the right of the barrel and left front edge of the receiver. Fitted with a smooth forearm and pistol grip stock with a black plastic buttplate. The stock and bayonet lug are fitted with sling swivels. "MC/39351" handwritten on the right of the buttstock in black marker. Length of pull is 14 inches. Includes a correct Remington M1917 bayonet dated "10 17", olive drab green plastic scabbard and olive drab green canvas sling.