Yes, there are detectors out there that can reach iron very deep, and if they go as deep as I did on that, they do very well! That said, I can cherry pick these targets and not dig any more iron all day, the canister shot, cannon ball, and one other small iron tool (?) were the only iron targets I dug the enrire day... that's 3/3. All other detectors I have used/tried you have to make the choice, chase iron and hope to get something good, or try and avoid it. For several years I chose to avoid it, until I started to try and understand it more, and now can't believe how easy it is to still dig it and not waste anytime finding the unworthy crap. (of course it's far from perfect and I only dig it at older sites) The explorer has very good disc. and the secret is knowing at what point the larger pieces break the null. I'm sure other units have their own tricks too, and maybe hit targets like that, but over all I can't imagine them being better in the sense I just described. BTW... Worthy to me is cannonball, trade axe, and larger items, I do have an interest in smaller relics like iron gun parts because I'm not willing to waste time chasing everything that size.
PS... I'd like to see what a IIb could do with a 15" coil in the right hands. (and decent ground) Also, good discrimination and digging targets in iron is much more important to me than getting 30" iron relics. But as I said, it was cool and made my day.