People v. O’Neal, 254 N.E.2d 559 (App. Ct. Ill. 1969)

“The witness testified that he received the gun and bullet in question at the laboratory; and the gun and bullet were introduced into evidence. He also testified that he fired the gun twice, and that he compared the test bullets with the one in question. He testified to the procedure generally used and to the reasons why a comparison of bullets will reveal the identity of the gun which fired them. On the basis of these tests, he was of the opinion that the gun found on defendant’s person fired the bullet found in the complaining witness’s coat. The expert witness set forth the reasons for his conclusion, and it was for the triers of fact to determine how much weight to give to his testimony. It should also be noted that the bullet and gun in question were introduced into evidence, and that defendant was not foreclosed from conducting similar tests, either prior to or during trial.”




“Other jurisdictions also have allowed the conclusions of a ballistics expert even though demonstrative evidence had not been introduced. In McKenna v. People, 124 Colo. 112, 235 P.2d 351 (1951), the court held that the ballistics expert’s testimony was proper without the introduction of photomicrographs, stating that the latter were inaccurate to some degree. In State v. Wojculewicz, 140 Conn. 487, 101 A.2d 495 (1953), the court held that the introduction of the test bullet is not essential to the admissibility of the expert’s testimony. And in People v. Buckowski, 37 Cal.2d 629, 233 P.2d 912 (1951), it was held that the oral testimony of the ballistics expert as to the bullets in question was sufficient to support his conclusions.”







Hinton v. Alabama, 571 U.S. 263

Note: there are several lower court rulings on the standard applied to expert testimony on firearms identification.










Davidson v. Cunningham, 2017 WL 3738560 (E.D.N.Y. 2017)

Note: there is no limiting testimony ruling, but the defendant argues that the issue with the tesimony was that the expert testified to “a reasonable degree of certainty” and should have been limited to testifying “more likely than not.”










People v. Smith, 2014 WL 1493905 (App. Ct. Ill. 2014)

The court did not limit the testimony of the experts, but that may have been due to the experts limiting their own testimony: “Additionally, like the experts in Robinson, Mayland and Stevens testified that their conclusions were their subjective opinions based on their comparisons of the characteristics of the bullets and fragments. Neither testified that their opinions were scientifically certain, and Mayland specifically testified that he could not attach any type of probability to his identifications”




“Like the defendant in this case, the defendant in Robinson argued that the trial court should have excluded the toolmark and firearms identification evidence under Frye because it lacked a scientific basis. The court disagreed, finding that, while “federal and state courts have had occasion to revisit the admission of expert testimony based on toolmark and firearms identification methodology,” the courts have “uniformly” concluded that toolmark and firearms identification methodology is generally accepted and admissible at trial.”







State v. Legnani, 951 A.2d 674 (App. Ct. Conn. 2008)

Note: The court failed to address the Defedant’s reliability arguments: “The defendant argues that Jachimowicz’ testimony regarding the matching of cartridges to magazines exclusively on the basis of magazine marks should have been subjected to Porter scrutiny because it is not generally accepted in the scientific community. Furthermore, the defendant argues that when a subjective methodology is applied, as it was in the present case, the court must determine whether the principles underlying the particular procedure were applied properly to the facts of the case. Additionally, the defendant argues that even if the methodology used in this case was generally accepted, it was subjective, and, therefore, the court had to determine whether it was applied in a reliable manner. Finally, the defendant argues that the lack of recorded methodology and Jachimowicz’ failure to record the type of tests he had performed *419 rendered his testimony “incapable of assisting the jury in any meaningful way **687 because [it] could not independently assess whether his methods were reliable and, thus, his ultimate conclusions valid.””
“The state argues, and we agree, that the defendant failed to establish that the tool mark identification evidence involved an “innovative scientific technique” and, therefore, that Porter does not even apply. In State v. Porter, 241 Conn. 57, 698 A.2d 739 (1997) (en banc), cert. denied, 523 U.S. 1058, 118 S.Ct. 1384, 140 L.Ed.2d 645 (1998), our Supreme Court held that “scientific evidence should be subjected to a flexible test, with differing factors that are applied on a case-by-case basis, to determine the reliability of the scientific evidence.””




In the present case, the court found that it did not have to conduct a Porter hearing because the scientific principles of ballistics and firearms analysis are well established. Furthermore, the court held that “[t]ool marking is clearly a science and technology that can be measured, photographed, calibrated and enlarged.” As a result, the court found the evidence both reliable and relevant. In his brief, the defendant attempts to distinguish the process of tool mark identification that involves magazine marks from the general field of tool mark and firearm identification. The court did not abuse its discretion in concluding that the tool marking identification involving magazine marks is reliable and relevant as a part of the broader field of tool mark and firearm identification. There was ample evidence in the record to justify the court’s conclusion. On cross-examination, Stephenson stated that “[t]here’s only one method used, scientific method that we’ve all practiced and used within the field of firearms and tool mark identification, and that’s the comparison of two sets or more of random marks placed upon the contoured surfaces to compare those to find an agreement, a sufficient agreement between those two surfaces to make an individualization.” Furthermore, he stated that “[w]e all follow the same basic theory that an individual tool mark can be specified to an individual tool once we find that pattern agreement upon those surfaces of those two surfaces after we’ve made a conclusion of looking at those for the relative spatial relationship, size and number and quantity of those striae that are upon those surfaces.” Finally, Stephenson testified that “[t]he firearm is a subcategory of tool mark identification. The firearm now becomes a tool. The objects that come—that they come in contact with are the unknown or what you’re trying to identify back to the tool, i.e., the bullet to the barrel, the cartridge casing to the magazine, the cartridge case to the firearm, the breach, the extractor, the ejector, the firing pin. Those all become tools that come in contact with those surfaces. And it’s all based on an identification of those unique patterns of striated or impressed marks upon those surfaces.” Stephenson’s testimony reveals that identifying marks made on the magazine by the cartridge casings is merely a subset of the science of firearm and tool mark identification, which has been well established and admissible evidence under prior case law.