A martial variant of a John Browning designed sport gun, the 520 Trench Gun 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 to 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 are sent back into the field for Vietnam. A combination bayonet lug and 6-hole heat shield is mounted on this example, with a two-line gauge marking on the left side of the barrel, the three-line address on the opposite, "P/(ordnance bomb)" proofs, cylinder choke and a 2 3/4 inch chamber. The frame is marked "P/(ordnance bomb)", "MOD. 520-30" and "U.S." with the post-1920 upper tang safety switch and the locking block in the top of the frame. Smooth metal jacketed forearm and pistol grip stock, with a green canvas sling, serrated plastic buttplate, and a 13 3/4 inch length of pull. With a U.S. Remington 1917 bayonet, 21 1/2 inches overall, 16 3/4 inch blade, wood grips and a "M-1917" marked sheath.

Very fine, with 85% of the original blue finish, showing some light spotting and handling marks overall, cycling wear on the magazine tube, and bright edges. The bayonet lug shows 85% of the original plum color, with some spotting on both sides near the muzzle. The stock is also very fine, with some mild dings and scuffs. The bayonet is very good, with some mild wear. Mechanically excellent.