Firearms & Toolmark Examinations
Our forensic scientists have the resources to analyze firearms at our laboratory in order to determine functionality as well as to generate test fires for the comparison of bullet and cartridge cases. Whether it is the reconstruction of an indoor crime that occurred within an enclosed bedroom or an outdoor drive-by shooting scene, we can assist in determining what most likely transpired at the scene and provide you with the decision-making information you need.
Firearm Mechanism Examination (Function of Firearms)
Our firearms examiners can examine and test the condition and functionality of firearms to determine if a weapon functioned properly during a case incident. We can also perform test firing of the firearm and generate exemplar bullets and casings for comparison or for issues regarding some aspects of shooting reconstruction such as distance determinations or ejection patterns.
Firearm Serial Number Restoration
Manufacturers often stamp serial numbers onto products such as firearms, tools, cameras, watches and automobile parts. These numbers can establish ownership or manufacturer identity. Individuals may attempt to obliterate serial numbers by scratching, filing, grinding, over-stamping or welding new metal onto an obliterated area. Our scientists attempt to restore obliterated serial numbers through physical and chemical methods.
Cartridge Case Ejection
Semi-automatic and fully automatic firearms eject fired cartridge casings from the firearm during the normal course of operation. Our scientists can analyze the pattern of ejected cartridge casings to determine a range of the shooter’s location or weapon at the time of discharge. This can add valuable information when performing shooting incident reconstructions.​
Toolmark Examinations
A toolmark is an mark that results from contact with sufficient pressure between a tool and a surface. The examination process involves comparing the impressed or striated surfaces of the “tool” to the striated surface within the questioned tool mark. During this examination, our scientists can also examine for additional trace evidence such as hair, fiber, and fingerprint evidence.
Comparison of Bullets, Cartridge Cases, and Toolmarks
Fired bullets and cartridge cases recovered from crime scenes can be examined to determine the number of firearms involved and whether a specific firearm was used. Our Firearms Experts use comparison microscopes to analyze and document this evidence, prepare detailed reports, and provide expert testimony in court. They can also review firearms and toolmark analyses conducted by other laboratories to assess the accuracy of the work and help interpret the results.
Make and Model Determination
Make and model determinations are performed when fired bullets and/or cartridge cases are recovered from a scene, but no firearms are found. The bullets and cartridge cases can be examined and the class characteristics of the markings can be categorized to generate a list of firearms that could have potentially fired the evidence. This information can provide potential investigative leads.
GSR Analysis
Gunshot Residue analysis, or GSR, is the detection of minute particles expelled by a firearm when it is fired. When the primer in a shell casing is ignited, a cloud of tiny particles, imperceptible to the naked eye, is expelled from the firearm. These minute particles are expelled primarily from the barrel of the gun but form a cloud emanating in all directions. An adhesive substance, typically a GSR Stub, is used to collect a sample from the hands or clothing of the suspected shooter. A scanning electron microscope (SEM) is subsequently used to analyze the surface of the stub for three common elements of gunshot residue – lead, barium and antimony.
Our firearms experts will work with you on any and all aspects of the process – collecting samples for GSR analysis, procuring GSR analysis of the evidence samples, and expert review of the GSR results. Each of our firearms experts has over 20 years of expertise in GSR sampling and interpretation and we can help you decide if GSR is right for your case and what the results mean if testing is done or has already been done.