Tony,
These finds can be used as a learning tool for ya. But I have to ask, What was your sweep speed? Fast, medium, or slow?
How do we explain how fast our sweep speeds are to each other?
Anyway, in my humble opinion, when the sweep speed is too fast, some junk targets will beep as good. And as Rick has mentioned, some will beep on the outer edge of the coil. He also mentioned that iron isn't constant.
Some of the iron targets you did dig, by the sound would prolly cause me to dig them as well. I think the iron targets that have a hole in them might beep as a worth-while target.
In the all-metal mode, some targets would have wailed very loud, indicating a big chunk of metal.
The iron square nails, again in my humble opinion, is a good indication that you will be finding some really deep finds. I know that sometimes they beep as good in my area. But when I check the target from a 90 degree angle, the target will null. I also check with the wiggle, and with a very slow sweep.
One other thing. Was your tone setting set at multi-tone, or single tone?
I once hunted like that and didn't realize I had it set to single. I felt like a silly rabbit for while.
Laterz
ed