I am looking for proper proof of the theory that it is called so due to the Norden sight of the B17, which was said to assist the bomber in putting a bomb into a pickle jar, and hence it stuck.
The accuracy of the Norden bombsight was often exaggerated, but it was never claimed it could put a bomb into a pickle jar. The exaggerated claim from the Norden Company was that a bombardier using it under "ideal" conditions could put a bomb into a pickle barrel from 20,000 feet AGL. In reality it could barely get within 100 ft of the target from 10,000 feet AGL. (AGL = Above Ground Level) Some sources claim that it's called a pickle switch because a control handle with many switches almost feels like a pickle with all its bumps, but that would imply the name was given considerably later than WW2.