Yes there has been a real cannon found. It was found around Bonsboro MD. There was a church adding an addition on and while digging for the foundation they came across a cave. when they looked into the cave they found a connon and other civil war things. Caves are very common in south central PA in Franklin county and northern MD in washington county. I'm not sure what ever happened to the canon and the other things. but one was found and its hard to tell what else is out there in those caves. I would love to get into some caves and do some detecting....