About 6” down in farm field not off beaten track. But read like iron. So probably just passed over many times. I saw the end of the barrel first and thought I had a piece of pipe.
Boy was I shocked when I pulled it out.
Scrub all the loose rust off, soak it in evaporust for a while and clear the barrel completely (make sure it's not loaded) then boil it in paraffin wax for a few minutes (bake it in the oven to make sure all the moisture is out first) when it cools buff it with a soft cloth and it will make a great display and last a long time without corroding any further