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Ballistics

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.

News and Updates

Projects and Programs

NIST Ballistics Toolmark Database

The NIST Ballistics Toolmark Research Database is an open-access research database of bullet and cartridge case toolmark data. This database will: foster the

Publications

NIST Ballistics Toolmark Research Database

Author(s)
Xiaoyu A. Zheng, Johannes A. Soons, Robert M. Thompson, Sushama P. Singh, Cerasela Constantin
In 2009, a report by the National Academies called into question, amongst other issues, the objectivity of visual toolmark identification by firearms examiners

Pilot Study on Deformed Bullet Correlation

Author(s)
Zhe Chen, Jun-Feng Song, Johannes A. Soons, Robert M. Thompson, Xuezeng Zhao
Most studies on bullet identification address test fire bullet that have near pristine striation marks on the land engraved areas (LEAs). However, in case work