Specifications
The launchers consisted of a steel tube closed at one end by a steel baseplate, resting on a wooden platform. The 675-pound (306 kg), 5-foot-long (1.5 m), 13-inch-wide (330 mm) shells fit around and on top of the tube, instead of being dropped inside, comprising a type of spigot mortar. The range of each shot was adjusted by adding different size powder charges at the base of the round. The barrels could only handle five or six shots apiece before becoming damaged and unusable. When used in large groups, as was often done, it produced a fearsome effect known as "the screaming Jesus" to U.S. Marines. To absorb the massive recoil caused by firing their projectiles, the mortar tubes were almost always placed up against a mound of dirt.
Read more about this topic: 320 Mm Type 98 Mortar