A recent Oregon Court of Appeals ruling blew a gaping hole in the state police crime lab’s long-standing technique of matching a suspect’s gun to shell casings left behind at a crime scene. The court found that a forensic examiner relied on “subjective judgment” based on training and experience – not objective scientific methodology – when linking shell casings in a 2018 Portland shooting to a Taurus handgun.The decision threatens an untold number of similar prosecutions across that state that have relied on ballistic comparisons. It already has left prosecutors scrambling to adjust trial tactics while defense attorneys hope the...