When someone documents their collection of 161 rings .....and their numbers on ANY machine , come in at a certain range , it DOESN"T MATTER how he dug them , whether there was iron around or Pink Elephants around !!..... The FACT remains that for his machine , THESE ARE THE RANGES HE GOT FOR RINGS FOUND WITH HIS MACHINE !!! ......How can data that someone got from their machine posibley be BIASED ? ...... What does Iron have to do with it ? ....... This data was not even from a Minelab machine ..... I think that it's safe to say that other machines besides the Sovereign have pull tab ranges, and Gold ranges , and Silver ranges, and Aluminum ranges , and Iron Ranges , and all kinds of other ranges ...... There is no possible way that this statement could be biased ......Biased against WHAT ? ........ You can draw whatever conclusions you want from what was found and the ranges that they were found in , but BIAS is SURELY not one of them ..... He's not trying to prove anythhing , he'a merely making a statement ...... Tell me how someone can be biased by simply making a statement ......You may want to know his entire proceedure , but that does not make what he is saying biased at all ..... Jim