Took the new Garrett ACE 400i for it's maiden hunt today after work. It took about 45 minutes to get re-orientated to the conductivity number designations. They are somewhat different from the AT Series. The AT Series read pull-tabs at about 53. The Garrett 400i tends to bang on them at around 76. However, copper/signals read in the high 80's to low 90's. And our Canadian dimes, quarters and loonies bounce back and forth with numbers ranging from 70's - 80's -90's. After a while, I guessed on digging up a clad dime and quarter, and was correct. One of the older pull-tabs with more mass on it then the newer ones did read in the 80's.
The ACE 400i is very sensitive to tiny targets, as shown in the pic above. Junk targets tend to bell-tone in one direction, but not the other. But, you should still play with the target running the coil over the target in different directions to get a more accurate idea of what's in the ground. And as usual......if in doubt, dig it.
If the weather holds up, I will probably try a relic hunt soon.