Printer Friendly

Measurements completed for 20 RM 8240 standard bullets.

Scratches on a bullet recovered at a crime scene can be as incriminating as fingerprints. Unfortunately, methods for analyzing these tell-tale forensic "signatures" still entail manual comparisons, making firearms-ballistics databases impractical. NIST scientists, with input from industrial and government partners, developed "standard" bullets--bullet-shaped artifacts with a series of surface profiles that can be used for testing the forensic equipment and operators. These standard bullets, officially called Reference Material (RM) 8240, are still under-going final testing.

Surface profile measurements of 20 RM 8240 standard bullets were completed in April 2003. These measurements were performed with a newly developed NIST bullet signature measurement system. A NIST proposed parameter and algorithm are used for quantifying the bullet signature differences between the RM bullets and a virtual standard for the bullet signatures. The virtual standard is a set of six digitized surface profile signatures, originally obtained from six master bullets shot at the Bureau of Alcohol, Tobacco and Firearms and the Federal Bureau of Investigation, using six different guns. By using the virtual signature standard as tool path information in a numerically controlled diamond turning machine at the NIST instrument shop, the 20 RM bullets were produced. The NIST proposed algorithm uses auto-and cross-correlation functions (ACF and CCF) for quantifying bullet signature differences. When the two compared signatures are exactly the same (point by point), their CCF would be equal to 100%. Measurement results showed that the CCFs for all 120 profiles (6 profiles on each of 20 bullets) are higher than 95%, and most of them are higher than 99%. These results demonstrate the high reproducibility of both the manufacturing process and the measurement system for NIST RM bullets.

A NIST associate from Drexel University and NIST scientists developed the measurement program. The measurement data will undergo further statistical analysis at NIST. A NIST workshop is scheduled for early June, preceding availability of the RM bullets to forensic agencies nationwide.

CONTACT: John Song, (301) 975-3799; jun-feng.song@nist.gov.
COPYRIGHT 2003 National Institute of Standards and Technology
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2003, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:General Developments
Publication:Journal of Research of the National Institute of Standards and Technology
Date:Jul 1, 2003
Words:326
Previous Article:Publication available on Korea's standards and conformity assessment system.
Next Article:AFM probe developed for [M.sup.3].
Topics:


Related Articles
New photomask designed for SEM magnification calibration. (News Briefs).
Standard bullets--soon a reality. (News Briefs).
Initial tests show high performance of NIST RM 8240 standard bullets. (News Briefs).
A shot in the light: precise bullet replicas take aim at crime-fighting standards.
Standard bullets project featured in Science News.
NIST issues reference material 8457 to aid orthopedic implant manufactures and researchers.
Commander's Emergency Response Program (CERP).
SRM 2460/2461 standard bullets and casings project.
Preparation of reference material 8504, transformer oil.

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |