The Remington Model 10 shotgun did indeed see service in WW1 along with Winchester's Model 97 but the Model 97 was first (proving the concept) and many more of them were used during the war. When Winchester could not keep up with demand, the government asked Remington to militarize its Model 10. Because of patent infringement (business trumps war) Remington had to devise a different bayonet mount and used a wooden heat shield. Both shotguns employed the slam fire mode. The Model 10 did have an advantage in that both the loading and ejection of cartridges was through the underside opening. The Model 97 had an opening on the underside for loading, an ejection opening on the side and a hammer-cocking opening at the back-- three places where dirt and mud could foul the weapon instead of just one.