Why did the Nazis claim that the Russians were firing ‘barns’ during World War II?

In 1942, the Red Army adopted M-30 rocket launcher shells. They were more powerful than their predecessors, but their large size meant they couldn't be fired from the ‘Katyusha’ launcher.

So, simpler launchers, with adjustable angles, were then developed for the M-30. Shells were loaded onto these launchers directly in the boxes used for transport.

The boxes actually served as guides for the shells. Their interior surfaces were lined with metal strips to ensure smooth sliding during firing. Launching was accomplished using a standard electric demining machine and a set of cables.

Before firing, the spacers that held the shells within the frame during transport had to be removed. This was stated in the instructions. However, the soldiers usually rolled cigarettes out of these instructions without reading them.

As a result, M-30s would, sometimes, fly off toward the enemy, right along with their crates. So the Germans began to say: "The Russians are crazy, throwing barns!"