Definition of pickle barrel in US English:

pickle barrel

noun

  • 1A barrel for storing pickled food.

  • 2U.S.A.F. slang. A (small or precise) target. Chiefly in phrases suggesting accuracy in bombing, especially in "right in the pickle barrel" and variants.

adjective

  • US Military slang. Of bombing, etc.: precisely aimed; extremely accurate.

Origin

Mid 19th century. From pickle + barrel.