I hunt beside an Mx sport and a V3i and we do lots of signal comparing. I'll hang onto my 800 thank you. Lots of deep coins being called iron.
I have noticed that will happen rarely on super deep stuff and usually when you are not using the correct swing speed for the sat setting. but in all metal it still sounds good and not like iron. Question is, was the nox seeing what was there as well? I imagine it was. I have found the nox to excel over the sport in mineralized ground and trash mostly, depth has been pretty comparable in mild sites.