While metal detecting an early artillery/arsenal with land owner's permission... I have found many cannon balls. However on February 4th I was digging an area that I had walked over many times and got a signal that had proven to be artillery shrapnel in the past. This time I decided to dig it! At first I believed it to be another 32lb solid shot...until It did not break free as the others normally do. I dug down some more to uncover something I had never seen before.
After emailing an artillery expert it has been identified as a proofing artillery projectile used to test cannons after being moulded. Expert says extremely rare. Most have never heard of these proof shots and it's a first for me! The CTX 3030 is a artillery freak! The second picture is my best day at same spot. Good luck out there!