Well, this is what the linked article says about it:

Prior to September 2005, comparative bullet-lead analysis was performed on bullets found at a scene that were too destroyed for striation comparison. The technique would attempt to determine the unique elemental breakdown of the bullet and compare it to seized bullets possessed by a suspect.[47] Review of the method found that the breakdown of elements found in bullets could be significantly different enough to potentially allow for two bullets from separate sources to be correlated to each other. However, there are not enough differences to definitely match a bullet from a crime scene to one taken from a suspect’s possession.[48] An additional report in 2004 from the National Academy of Sciences (NAS) found that the testimony given regarding comparative bullet-lead analysis was overstated and potentially “misleading under the federal rules of evidence”.[47] In 2005, the Federal Bureau of Investigation indicated that they would no longer be performing comparative bullet-lead analysis.[49]