In the trench gun configuration, the Model 12 has a perforated steel heat shield and the M1917 bayonet adapter, very similar to the Winchester Model 97 trench gun As a riot gun, the barrel was plain with no heat shield and no bayonet adapter.
Winchester Model 12 Trench Gun (TM 9-2117, July 1957).
By the time World War II began, stocks of shotguns were too small to support the mobilization and new orders were placed. The
well regarded Winchester Model 12 trench and riot guns were again procured with a total of more than 80,000 guns ordered by the U.S. Government by 1945, more than any other combat shotgun of the time. Collectors will notice that there was a change in the ventilated heat shield during WW II from the WW I design of six rows of holes to only 4 rows starting in 1942.
In the photo to the left, a Marine on Blue Beach 2, Okinawa (1 April 1945) is armed with a Winchester Model 12 trench gun as assault troops of the 1st Battalion, 7th Marines go over a seawall after landing unopposed.
The mobile warfare of the European Theater of Operations had little use for the shotgun, but on the islands of the Pacific Theater it was entirely different. There short range combat in the jungles or against Japanese bunkers, caves and unseen snipers was the norm. The Marine Corps had combat shotguns in almost every unit and their use has been documented in most Pacific battles. When facing this type of combat, the shotgun was superior to every infantry weapon available in WW II except perhaps the Thompson and M3 submachine guns.
The Model 12 remained as the primary combat shotgun, used heavily by the USMC in Korea and until the Vietnam War where they again served. The Model 12s still in Government inventory were quickly exhausted early in the Vietnam War and newer, less expensive shotguns were procured. Winchester stopped producing the gun in 1963 (except special order). The Winchester Model 12 was superseded by the Remington Model 870 and Winchester Model 1200.
Description of the Winchester Model 12 Shotgun
The Model 12 combat shotgun is hammerless with a streamlined receiver, a 20-inch cylinder bore barrel and a tubular magazine holding five shells. The action feeds from the bottom and ejects from the right side. Like the closely related Winchester Model 1897 (or M97), the Model 12 has no trigger disconnector -- with the trigger depressed, shells can be fired as fast as the forearm can be pumped.
The M12 magazine tube and the barrel can be removed from the receiver for takedown.
Books and Manuals for the Winchester Model 12 Shotgun
The military technical manual is TM 9-2117 titled "Field and Depot Maintenance, Winchester Riot-Type Shotgun M12 and Stevens Riot-Type Shotguns M520-30 and M620A". This Department of the Army Technical Manual is dated July 1957.
Find More Information on the Internet
There are many fine websites that have additional information on this
topic, too many to list here and too many to keep up with as they come and go.
Use this Google web search form to get an up to date report of what's out there.
For good results, try entering this: model 12 shotgun. Then click the Search button.