Staff Writer (Updated: 9/26/2016):
The Model 1897 held an inherent "benefit" in which the trigger could stay pressed and the operator manage the pump for successive repeating fire - a powerful quality in short-range combat (the method known as "racking shells" or "slam firing"). This was carried over into the equally-popular Model 1912 which also saw service in World War 1 and World War 2.
At the start of World War 1, the American Army lacked much of the fighting tools required of war. With its commitment to war in Europe beginning in 1917, all manner of weaponry was procured - both foreign and domestic - to which many firearms producers sprung into action to net the potentially lucrative military contracts to follow. The Model 1897, already a popular firearm in America, was selected for military service as the "Model 97". It appeared in the basic Standard, Riot Gun and Trench Gun forms. Riot Guns were essentially Standard forms fitted with shorter barrels and intended to serve in guard duty. Trench Guns were given the military treatment, complete with shorter 20-inch barrels, a perforated heat shield over the barrel and mountings for the American Model 1917 field bayonet. The Model 1897 became the first shotgun to be selected for military service by the US Ordnance Department.
As a combat weapon, the Model 1897 proved resilient to the abuses of the modern battlefield, able to withstand damp conditions, dirt and debris and getting slammed about while still keeping its robust qualities. Such qualities are what endeared fighting men to their weaponry and the Model 1897 did not disappoint in that respect. As the war, once a fluid and mobile beast, had now ground down to a stalemate of trenches lining the European countryside, it was seen that short-ranged weapons to help clear such trenches were of particular value. America had always gone to war with shotguns since the 1850s and World War 1 proved no different where the Model 1897 was concerned, acting with exceptional brutality against entrenched foes. The Winchester Model 1897 fought alongside another drafted Winchester product - the Model 1912 (M12) - which served the same form and function as the Model 1897. The Springfield Armory had to design a special bayonet mounting for Winchester shotguns as the bayonets in use relied on a ring fitted over a .30-30 service rifle barrel. Model 1897 shotguns featured a substantially larger diameter barrel so an underslung mounting was developed in which an adapter fit over the barrel and the bayonet seated into the adapter. Use of a bayonet did not impeded the slide function though it made the overall weapon lengthier and, perhaps, a bit more cumbersome. Both the United States Army and Marine Corps retained their Model 1897s in inventory in the decades following the November 1918 Armistice.