This is a kind of shotgun. One shot fills the other. It's very fast. What is that?

The reason why the US military adopted Winchester 1897, just like the development of M191KLOC-0/pistol, was that the weapons at hand of American soldiers could not effectively prevent the enemy from charging forward in the US-Philippines war. At that time, the US Army Command urgently purchased Winchester 1897 and gave it to the US troops stationed in the Philippines for use, which performed well in actual combat. This shotgun was also used in Pershing's campaign against Mexico in 19 16. After joining the First World War, based on the experience accumulated in trench warfare, the US military thought that it would be more effective to shorten the barrel of the pump-driven shotgun (because there was no submachine gun at that time), so the US Army Command ordered the development of a shotgun for trench warfare.

M 19 17 trench gun is called "trench gun" in France because of its short barrel, bayonet, fast pumping speed, 6 rounds of firepower (plus in-bore 1 round) and close-range hit rate and killing effect of 12 shotgun. There is a legend here: the German government strongly protested that the United States violated international conventions and used trench guns as an inhuman killing weapon; Moreover, castle wolfenstein claimed that all American soldiers carrying trench guns were executed immediately after being arrested. The U.S. government formally refuted the German government's protest, and the U.S. Army also said in a tit-for-tat manner that Germany dared to execute 1 American soldier with trench gun, and the U.S. would find a German prisoner to pay for his life. In the end, the German protest was invalid and neither side retaliated. However, it is said that the German government announced the execution of American soldiers carrying shotguns without relevant documentary evidence, which may be just an unwritten rule, or some frontline officers are afraid of revenge with shotguns. However, the German government did issue a diplomatic document in 19 18 to protest against the use of shotguns by the United States, but the effect of this protest document was equivalent to a successful commercial advertisement of shotguns. Finally, the Germans developed their own trench warfare suppression weapon-MP18I submachine gun.