I've seen one in action 4 years ago and dude was pulling dropped US .58'S at IMO 18 -20 + INCHES in a damp lower lying area right next to the Kennesaw Mountain Battlefield , other machines could not hear them at all including a Whites TDI but that guy located a nice SC Cuff that he only showed to 3 or 4 people and I was not one of them but I did see it later at the club meeting . That hunt bordered the National Battlefield Park where 8 Million dollar homes were being built 3 were finished & our club members had a day to hunt it and share the finds with the 3 homeowners and the builder but when 2 dozen people showed up they quickly re*igged on the deal and ran us off after 2 hours; needless to say the homeowners and the builder only got a few fired minnies and Iron 'what is it's'.
Oh also the Park Rangers had put up cameras in many places and a few guy's where watching through binos , they actually said they were there looking for poachers as this was in early December . Ill add to my 'book' of a reply here (LOL) , several of the oldtimers had already scoured that area years and years before the Park added that land in the 1970's. . They must have kint picked as most there found a few fired Minnies and Roundballs . Except for the guy with the GPX and his drops. Sorry so long I need to get out more.