How would you interpret ‘four hundred twenty’ and ‘minnenwerfer’ in the second line. 1 How would you interpret ‘four hundred twenty’? Does it refer to the caliber of the guns? 2 Do you know the meaning of ‘minnenwerfer’? Is it some kind of gun? Thanks. It’s from A Farewell to Arms by Ernest Hemingway (Chapter 9). the context: Something landed outside that shook the earth. "Four hundred twenty or minnenwerfer," Gavuzzi said. "There aren't any four hundred twenties in the mountains," I said. "They have big Skoda guns. I've seen the holes." "Three hundred fives." We went on eating. There was a cough, a noise like a railway engine starting and then an explosion that shook the earth again. "This isn't a deep dugout," Passini said. "That was a big trench mortar." "Yes, sir."