I love the depth my CZ 70 gets but the target ID is driving me nuts!!. When it shows a target on coin, on the far right side, a lot of times it is a aluminum can!! The only way I found to descern between can and coin is a short beep and a can covers a larger area than a coin but why does aluminum show up in coin even in the so called preset coin mode? Is it possible it may need tuning or is it supposed to do that? Please help before I throw this in the river!!