Just don't think I'm getting deep enough

[digger460]

It rang a solid 82, which is why I originally dug. When I originally start digging, I went over it again, and just the corners of the top cover of what I think is a tractor, rang 82. Alot of iron on property has those high tones, which is really aggravating. Went out yesterday, but didn't get to dig it up to get a picture, because only had about an hour. Hope to get there this weekend. Thank god it's sandy soil!

Also was running Pro Zero, full sensitivity, do disc.