OK, so this has got me a bit confused. I usually hunt with the high FE numbers (27+) blacked out. If I'm swinging and get a promising but weakish signal (say 17-45 and the like), I figure it is either a good target, or iron falsing. So I go into quickmask (which is totally all metal in my setup), and swing over the target, and if 9 out of 10 swings or so show FE numbers in the 30s, (generally 35 the way it has been working out), I assume it is an iron target and move on. What I look for is the conductive target has to put up a fight, and it least ring say 30% of the time, for me to deal with the target.
Turns out I think this may be stupid, and I think I'm completely confused. I got one today which sounded good at first, then pretty much every swing in quickmask showed FE 35. I decided to dig anyway, just to keep myself honest, at it was a wheatie at just 6 inches. No iron to be found anywhere. I scanned the hole again, no signal, no iron. So I'm wondering why it was almost always showing FE 35?
I decide I'm going to dig the next one like this as well -- it was showing 11-12 inches, an occasional conductive reading, but over 90% of the swings on the target were FE 35. Was a merc at 9 inches, on its side. So, that's my story, FWIW. I guess you have to dig those FE 35 signals when they are deep, and live with iron. I dunno. My understanding was conductive targets would top out at about FE 26 or so. I guess I was wrong, and I can only imagine the silver I have passed up.