Last night I took a few minutes to use the Compadre in the yard next door to ours. This small pin (little larger than a quarter) was a hard momentary hit for the machine. It was buried almost 6 inches down in sandy root laden soil. Not sure what it is, looks like there might have been a stone or other inset items. As it is the piece is quite heavy for it's size. Got to love that simple little Compadre. I know a number of expense machines have passed over this area and missed it.