In 1943, when three SS officers came to HYDRA Headquarters to question Johann Schmidt about HYDRA's failure to deliver promised weapons to the German armies in the front lines, Schmidt showed them his Tesseract-powered cannon. But when they discovered that Schmidt intends to nuke Berlin and owerthrow the Nazi Führer Adolf Hitler, Schmidt used the cannon to vaporize them all. That was a clear sign of his breakaway from Nazi Germany.
Soon, similar cannons were installed on several HYDRA vehicles, including the tanks. In November 1943, when Captain America freed four hundred Allied prisoners from a HYDRA factory, they used one of those vehicles to escape, and destroyed much of the factory with the cannon.
In April 1944, Captain America invaded a castle controlled by HYDRA on an island in the Nazi occupied Danish straits. After he defeated a soldier equipped with the advanced exo-skeleton battle suit, he commandeered a vehicle and killed several HYDRA soldiers with the cannon.
By the beginning of 1945, HYDRA's super bomber, the Valkyrie, was finished. The plane was armed with several HYDRA cannons. When the United States Army attacked Schmidt's last base, he flew away with the intention to bombard New York City. When Captain America followed the bomb-loaded plane in a flying bomb, Schmidt shoot at him, but his shots all missed.