The witness did testify that he was not a ballistic expert, but that he had had much experience in the work of identifying firearms; that the term “ballistic expert” did not apply to his line of work. In this the witness may be technically correct. But, be that as it may, the witness’ testimony disclosed that he was an expert in the identification of firearms and bullets by the comparison method by means of a microscope. The method used in this case to identify the shells and revolvers was similar to the method employed in the case of State v. Shawley, 334 Mo. 352, 67 S.W. 2d 74, loc. cit. 80. The question was there fully considered and it was held that the witness was qualified to testify. The rule is now well settled that such evidence is competent and may be considered by the jury in arriving at a verdict.