Always Curious --
So far, as far as I can tell, there is ONE type of pulltab that can hit at 13, or a 13-14 bounce, and unfortunately it's a common one in some areas. I THINK it's Coke/Diet Coke, but not sure. In any case, where I hunt there aren't too many of those, most are a tad higher, but I hear you. I would LOVE to have Minelab "spread out" the VDI range. There's room, too...not that much that we are likely to dig rings up in the 30s...so quarters, halves, and dollars could maybe be compressed into the high 30s, instead of spread throughout the whole 30-40 range. That would leave more room for "separation" in the mid ranges...
Anyway, just a thought.
Meanwhile, Ksdirt, on a rusty cap, I have seen the same thing. I hit them around "11," and though there seems to be some audio clues in there (too early for me to tell for sure), switching to 5 kHz and seeing a jump into the mid 20s to 30s is a definitely giveaway that it's rusty steel...
Steve