As you probable already know, the accuracy of discrimination circuits are greatly dependant on depth. Were the wheat cents you mentioned fairly deep?? wheat cents are right on the border of being disc'd out in the coin check mode, and the deeper they are in relation to the coil, the closer they will come to "no mans" land.(out of the coin checks range) The deeper they are, the lower the machine will read them on the conductance scale. This is true of any detector. In ideal conditions, the disc circuit will nail a wheat back every time in zinc check, but that changes with depth. As far as the response on the V nickel, you may just have been in close proximity to another target(unseen), and were enhancing the response of the V nickel due to the proximity of the other target. V nickels are funny critters however, due to their composition, and rarely fall into any particular range. A lot of "iffy targets will give a "click", or "chirp" in coin check, despite their relative low conductivity, but you'll note, when checked in the range they actually fall in, they respond with a clear clean signal. You also have to keep in mind the type of field generated by the 9" coil. It isn't the classic "V" shape found on most detectors. Its more of a bloated "U" shape, and consequently gives you a far greater field of detection at depth. The 5 simply "sees' a lot more than most detectors do in any given swing of the coil. This is a very good argument for having a 7" coil in your detector bag, to hunt trash riddled sites with. Less target overlap, but still with lots of sensitivity and depth. One other thing of note is, that when switching to coin check, there will be a small delay while the circuits are being charged, and you wont get an accurate reading for one or two sweeps. (depending on your sweep time.) also, be sure to make very narrow sweeps when trying to ID a target, to try to avoid input from adjacent targets. hope this helps..

Streak!