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 Forensic Science
      Firearms and toolmarks

	  			
  Overview
				What is forensic ballistics? Forensic ballistics involves the examination of evidence from firearms that may have been used in a crime. When a bullet is fired from a gun, the gun leaves microscopic marks on the bullet and cartridge case. These marks are like ballistic fingerprints. If investigators recover bullets from a crime scene, forensic examiners can test-fire a suspect’s gun, then compare the marks on the crime scene bullet to marks on the test-fired bullet. The examiner will then assess how similar the two sets of marks are and determine if the bullets are likely to have been fired from the same gun or different guns. Cartridge cases are compared in the same way.

**What we do**

For roughly a century, forensic ballistics experts have been comparing bullets and cartridge cases by visually examining them under a split-screen microscope. After comparing the bullets, the examiner can offer an expert opinion as to whether they match but cannot express the strength of the evidence numerically. NIST scientists are developing methods that will allow an examiner to attach an objective, statistically meaningful measure of certainty to their testimony. We also produce the NIST Standard Bullet and the NIST Standard Cartridge Case. These aren’t real bullets or cartridge cases, but precisely manufactured replicas of fired bullets and cartridge cases with known ballistic fingerprints. Crime labs use these standards to calibrate their instruments, which helps ensure that their examinations produce accurate results.
					Featured Content
      
                  Firearms and Toolmarks

	
	The Research
				Projects & Programs
  
Forensic Topography and Surface Metrology
                  OngoingThis project provides methods, standards, and services for characterizing surface texture and microform in manufacturing, forensics, and science. We seek toNIST Ballistics Toolmark Database
                  OngoingThe NIST Ballistics Toolmark Research Database is an open-access research database of bullet and cartridge case toolmark data. This database will: foster theStatistics for Ballistics Identification
                  OngoingNIST is making advances in the science and technology for identification of firearms and tool marks; SED provides statistical analyses and designs as a vitalUniversity of Texas, Arlington - RFID Smart Container Study
                  OngoingView All Projects/Programs
					Additional Resources Links
            FORENSIC SCIENCE PROGRAM
                                        Forensic Science Research Focus Areas
                                        Publications
  
  Kennedy Assassination Bullets Preserved in Digital Form
              NIST scientists used advanced imaging techniques to create digital replicas of these important historical artifacts. Learn more in our news story, blog post, and photo essay.
            Read the news story

  News
      How Good a Match is It? Putting Statistics into Forensic Firearms Identification
        On February 14, 1929, gunmen working for Al Capone disguised themselves as police officers, entered the warehouse of a competing gang, and shot seven of their rivals dead. The St. Valentine’s Day Massacre is famous not only in the annals of gangland history, but also the history of forensic science. Capone denied involvement, but an early forensic scientist named Calvin Goddard linked bullets from
            Read more
    
  Two New Forensic Firearm Examination Standards Added to the OSAC Registry of Approved Standards
            Read more

  NIST Launches an Updated Organization of Scientific Area Committees for Forensic Science
            Read more

  Divide and Conquer: New Algorithm Examines Crime-Scene Bullets Segment by Segment
            Read more
    

  
  

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