PROFICIENCY TESTING PROGRAM OF THE ENFSI WORKING GROUP "FIREARMS"

Dr. Ludwig Niewöhner

Within the framework of the ENFSI Working Group "Firearms" a proficiency testing program on the detection and identification of GSR by SEM/EDX was set up and performed. The test material was designed by the Bundeskriminalamt and manufactured on order by an external company for SEM accessories. The participating laboratories were requested to determine the total number of PbSbBa containing particles on the test samples following their own laboratory specific methods of automated GSR particle search and detection by SEM/EDX. The presentation summarizes the results of the study as well as a statistical evaluation and compares the current achievements with previous studies.

 

THE CALIBRATION OF BALLISTIC CHRONOGRAPHS

Lucien C. Haag, Independent Examiner, Carefree, AZ

Ballistic chronographs are useful in a number of forensic endeavors. Assessing ammunition performance, approximate muzzle velocity for a particular gun-ammunition combination, provides important data in exterior and terminal ballistic experiments and addressing legal definitions of “dangerousness” based on velocity, kinetic energy or energy density.

At present there is no established means of verifying the accuracy of such measurements. This presentation offers both a means for crime laboratories to establish the reliability of such equipment and a suggested testing protocol necessary for ASCLD LAB accreditation procedures.
 

 

THE EFFECTS OF CYANOACRYLATE FUMING ON TRIGGER PULL MEASUREMENTS AND BULLET IDENTIFICATION

Lucien C. Haag, Independent Examiner, Carefree, AZ

Cyanoacrylate (“Super-Glue”) fuming is commonly used to develop latent fingerprints on recovered firearms. This action typically precedes ballistic identification efforts and/or the measurement of trigger pull. Since this process coats the firearm with a layer of material normally used as an adhesive it may be argued that the presence of this material changes the character and forces involved in discharging the firearm. It may also be of concern insofar as bullet identification efforts since this material may deposit itself in the bore of the firearm.

This presentation shows the before and after measurements for three types of handguns subjected to heavy C.A. treatment: a Ruger Blackhawk single action revolver, a Lorcin striker-fired pistol and a Smith & Wesson double action pistol.

The heavy deposition of cyanoacrylate on the exterior portions of these firearms did not measurably increase their trigger pull values as determined with the Trigger Scan device nor did it compromise identification efforts for fired projectiles.
 

BALLOTING BULLETS: EXTERIOR AND WOUND BALLISTICS OF FIRED BULLETS, PHYSICAL CHARACTERISTICS OF FIRED BULLETS AND CARTRIDGE CASES

Lucien C. Haag, Independent Examiner, Carefree, AZ

A number of mismatched cartridges can be readily loaded and fired in certain firearms without difficulty. These include .380 Automatic ammunition in 9mm Makarovs, 9mm Luger in .40 S&W, and .270 Winchester in .30-06 rifles. The bullets ballot down the bore acquiring intermittent rifling marks and emerge with reduced muzzle velocities. Most of these bullets are not spin-stabilized and tumble in flight. As a consequence they have very poor exterior ballistic properties. Bullet holes and entry wounds produced by these balloted bullets will frequently reflect their tumbling nature with relatively low bullet penetration depths in tissue due to yawed impacts and reduced impact velocity.

The necks of the fired cartridge cases will expand to fit the chamber often without splitting. Nine-millimeter Luger cartridges must be manually extracted and ejected from a .40 S&W pistol whereas .380 Automatic cartridges will cycle the action of a 9mm Makarov.
 

LOCKS, THEIR FUNCTION, AND SURREPTITIOUS ENTRY

Clyde Roberson, Medeco Lock Company Salem, VA

A presentation designed to introduce the way locks work, how they can be compromised, and the types of marks left by the instruments used to effect an illicit entry.
 

THE IDENTIFICATION OF KEYS TO PROVIDE INFORMATION REGARDING SUSPECTS, ASSOCIATES, AND LOCATIONS

Marc Weber Tobias, Investigative Attorney, Sioux Falls, SD

Keys found on suspects, at crime scenes, in automobiles, and in the execution of search warrants can provide valuable information and leads for the criminal investigator. This power point presentation details critical information regarding keys, and how to identify the lock that they open and its potential location. Keys can provide leads as to locations where evidence may be obtained, as well as critical links to associates. This is especially important in view of the events regarding international terrorism.

This material is designed to provide criminal investigators and forensic specialists with a basic working knowledge of keys, how they are produced, and cut, and how they can identify the locks to which they fit. The material for this presentation is taken from Chapter 27 of LOCKS, SAFES, AND SECURITY (Second Edition), released in 2000, and written by the presenter. This is a 1400 page reference for law enforcement, and reflects 35 years of experience by the author in the bypass and analysis of locks and locking systems.
 

MOMMY, WHERE DO STRIAE COME FROM?

Michelle Kuehner, Allegehny Co. Coroner’s Office Pittsburgh, PA

There have been many papers in the AFTE journal indicating that striae on bullets (or wads) can come from a specific part of a barrel. This paper will review some of our earlier research and show how pin gauges and barrel casts can be used to assign particular striae on a bullet as having been made by a particular site in the barrel.
 

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