Stokes Mortar Firing Gas Shells

Adoption of a rifled barrel made it necessary for engineers to redesign each component of the mortar, from baseplate to shell fuze. World War I shells had had an allways fuze to make certain that the tumbling shell would explode no matter whether it landed on its base, side, or nose. Fuzes of this type could not be used in a spinning shell since centrifugal force would activate the fuze and cause the shell to burst as it left the muzzle of the mortar. After considerable experimentation, engineers developed a safe, dependable fuze that could be set for impact or time. 

For the baseplate of the Stokes mortar it had been feasible to have a steel cup, bolted to an oak plank. But recoil from the new 4.2-inch barrel soon pounded this type of baseplate into splinters, and a forged steel baseplate had to be produced. Finally in 1928, after several years of experimentation, model Ml 4.2-inch chemical mortar was ready for service.  

During the next decade CWS engineers put considerable thought into improving the standard model. The practice of digging an emplacement, which took time and reduced the mobility of the mortar, was abandoned 

CWS designated all mortars with the new barrel as model M2. The CWS carried the M2 into all theaters and some were still in aaion at the end of the war.  

Notwithstanding that the range of the mortar had almost doubled by 1944, troops in the field were still not satisfied. They wanted the weapon to hit targets 5,000 or more yards away. One means of accomplishing this was to devise a jet accelerator that would fit on the base of a shell and give it a boost after it left the barrel. The CWS started work on such a device, but soon canceled the project after a survey showed that development would take too long, and that men with the know-how could not be spared from other mortar projects.  

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