Serial number 744017V indicates manufacture sometime in the 1960s during the Vietnam War era, prior to 1968 when the “S” prefix serial numbering commenced. Offered here is a parkerized Remington Model 870 Mark 1 variant trench shotgun featuring the U.S. Marine Corps type bayonet adapter assembly with rifle sight and bayonet lug for use with the included M7 bayonet, the same bayonet used on M16A1 rifles, and the extended magazine tube with 7-round capacity. The Model 870 Mark 1 was the first type of military shotgun to fit the M7 bayonet, whereas all of the military trench shotguns before it fit the M1917 bayonet, and also the first to have a 7-round extended tube. Remington's military records are mostly unreleased, but it is well known that a number of Remington Model 870 shotguns in a variety of configurations were procured by the various branches of the U.S. military during the Vietnam War and after, and have been in service in various forms in security and combat roles throughout Operation Desert Storm of the Gulf War in the 1990s and into the Afghanistan War; with many military 870s known to be absent of U.S. property markings and in both blue and parkerized finishes. Related information on various military Remington Model 870 shotguns can be found on pages 240-260 of "The World's Fighting Shotguns" by Thomas F. Swearingen. A known U.S. Marine Corps contract for 3,231 Remington Model 870 Mark 1 shotguns was in Spring of 1969, which featured the bayonet lug adapter with rifle sights, a 21 inch barrel with modified choke, plain walnut furniture, and parkerized finish, in which page 193 of Bruce Canfield's book “Combat Shotguns” (2007) states, “The exact serial number range for the Mark 1 shotguns is not known and was not reflected in the Remington/USMC contract information.” Rock Island Auction Company has sold some Remington Model 870 Mark 1 trench shotguns in the "S" prefix serial range, and one Remington trials/salesman sample without the serial number prefix (Lot 339, Auction 86). Relevant information and photographs of Model 870 Mark 1 and riot shotguns can be found in Canfield's book (2007) on pages 162-163, 181-184, 191-194, and 218-223, in which page 182 of the book states, "The first significant combat use of the Mark 1 shotgun was reported to have occurred in May 1975 during the Mayaguez crisis when an American ship was captured in international waters by hostile Cambodian forces. U.S. Marines eventually recaptured the ship and participated in combat operations against the Cambodian perpetrators on a nearby island. The M870 Mark 1 reportedly played a large role in these engagements, and the weapon quickly gained a reputation as a reliable and effective combat shotgun." Many of the Mark 1 shotguns later had their front sights removed, and some have been reconfigured with 20 inch barrels, as shown in various official photographs in Canfield’s book. This Model 870 Mark 1 variant has been subsequently arsenal/armorer rebarreled with a “WA” 1980 date code 20 inch barrel assembly with the later type adjustable rear notch sight, and choke measuring modified. Two-line "12 GA. FOR/2 3/4 IN. SHELLS" and the date code marked on the left side of the barrel, with the two-line Remington address on the right. "Remington/744017V" and "Wingmaster/MODEL 870" marked on the left side of the receiver. Serrated walnut forearm and smooth pistol grip stock with a black plastic serrated Remington buttplate. 13 inch length of pull. Includes an olive drab green canvas web sling, and an Imperial M7 bayonet with green plastic M8A1 scabbard.