Defendant argued that the statement made by the expert that he did not measure the or photograph the width of the grooves and lands because the "comparison microscope is the highest and best evidence" should have been excluded. The court agreed and held that "when [the expert] omitted to confine his answer to facts, or to his opinion as an expert on bullet identification, and planted his reply in the realm of the judiciary by stating a legal conclusion, it was improper and prejudicial, and should have been ruled out on motion."