logo for print

New shell ejection study suggests gun handling determines where empties fall


In this edition:


I. What the New Shell Ejection Study Found


II. New Clue To Potential Danger


III. Should Red Be the Hot New Cop Color?





An expanded study of shell casing ejection patterns, with important legal implications for law enforcement, has just been completed by the Force Science Research Center, with cooperation of the Los Angeles County (CA) Sheriff’s Dept.


Details and an analysis will be reported in the next issue of Force Science News, but FSRC Executive Director Bill Lewinski says that the new research tentatively confirms that “how a handgun is held has a more profound impact on the ejection pattern than caliber, ammunition, design or make of handgun.”


FSRC became interested in this subject 2 years after Lewinski was recruited as an expert witness for an Arizona officer who was charged with murder in the shooting of a female driver whom he alleged threatened him with her vehicle. An issue of credibility arose when a firearms examiner adamantly claimed the officer was lying about his position during the incident, based on where a spent shell casing from his semiautomatic was found.


Two preliminary FSRC studies conducted with single shooters firing a total of 150 rounds concluded that ejected-shell placement can vary radically depending on how a weapon is held. After Lewinski’s testimony to this fact at trial, the officer was acquitted.


** For more, see

Force Science News #1



The new study involved about 60 officers from LASD, each firing at least 110 rounds with a variety of handgun models held in 11 different positions. “Without a doubt, how a gun is manipulated when shooting has a greater impact on ejection pattern than any mechanical influence,” Lewinski says. “With a study of this extent, the empirical reliability is very high.”


This automatically becomes the largest study of its kind--because it is the only study that has focused on physical manipulation as a factor in ejection patterning. “Everyone else has come at it from the mechanics of the gun, the quality of ammunition, even the spring tension of the magazine on the slide,” Lewinski explains.


“This is a tragedy. Because of inadequate and incomplete ‘evidence,’ officers have been erroneously charged with capital crimes. Ignorance has been used to accuse these officers. A study of this nature should have been done long ago, and with all the firearms experts around who claim to speak with authority on this subject, it’s absurd that it wasn’t.”


Under the coordination of Lewinski and Lt. Joe Hartshorne of the LASD Homicide Investigation Division, the latest research was led by Dave Karwoski, an FSRC Technical Advisory Board member with 30 years’ experience as a sheriff’s deputy and firearms instructor. He was assisted by Mark Peterson, a law enforcement student at Minnesota State University-Mankato, home of the FSRC.




Canadian researchers have added a subtle but potentially significant nuance to the old warning, “Watch the hands.”


A study at the University of Alberta has found that the length of a man’s index finger relative to his ring finger can be a predictor of his predisposition for physical aggression. The shorter the index finger is compared to the ring finger, the higher his potential for physical violence.


This sounds like lockup lore. Even the study’s co-author, Dr. Peter Hurd, thought the finger-aggression link was “a pile of hooey” until he studied the data. But Dr. Bill Lewinski, executive director of the Force Science Research Center at Minnesota State University-Mankato, says the finding has a firm foundation in human science.


“This is associated with the level of testosterone a fetus is exposed to when it is developing in the womb,” Lewinski told Force Science News. “Testosterone influences not only how the aggression-related centers of the brain develop but can also affect the evolution of fingers that is taking place at the same time. The more testosterone, the greater the impact.”


The effect tends to negatively influence the maturing fetus’s capacity for empathy and compassion, as well, Lewinski says. However, the study found no correlation between finger lengths and nonphysical forms of aggression, such as mere verbal abuse, anger or hostility. Nor does the finger-length finding appear to apply to women.


Because of personal variables within the general results of the study, Hurd cautions against drawing hard conclusions about specific people. But Lewinski points out that you should be watching the hands of subjects you deal with as an officer-safety consideration anyway and this is one among other potential indicators of trouble that you can take note of.


“More than anything,“ Hurd says of his study in a report published in HealthDay News, “I think the findings reinforce that a large part of our personalities and our traits are determined while we’re still in the womb.”


Hurd’s research group plans to continue its investigation of physical aggression by studying the relative finger lengths of hockey players to see if there is a correlation with the penalty minutes they rack up in a given season


More details of his recent findings appear in the March issue of the journal Biological Psychology.




Should police uniforms be red? Would that make you safer and more easily in control of touchy situations?


You might jump to that conclusion after a quick read of a new study by British scientists of results at the 2004 Olympics.


A research team from England’s University of Durham compared the performance of athletes randomly assigned red outfits or body protectors compared to those who wore blue in one-on-one competitions of boxing, tae kwon do, Greco-Roman wrestling and freestyle wrestling.


Those wearing red won about 55 per cent of the time, while those in blue triumphed in only 45 per cent of their contests. According to reporter Bryn Nelson writing in Newsday, the researchers conclude that “the evolutionary connections between the color red and male dominance or testosterone-driven aggression in animals may well extend to humans, perhaps providing a subtle lift or leaving an opponent feeling, well, a little blue.”


In other words, the person wearing red may receive a subconscious hormonal boost that builds confidence while his opponent experiences a subconscious hesitation that either causes that person to back off or provides a slight momentary advantage that the red-wearer can then capitalize on.


Before carrying these findings to the realm of police uniforms, however, Dr. Bill Lewinski, an expert in behavioral psychology and executive director of the Force Science Research Center, advises caution. Besides projecting an image of dominance, red can also be a sign of confrontation and can be seen as a challenge, he points out.


“To a friendly or neutral audience, it conveys confidence and assertion,” he says. “But to a hostile audience, it can invite confrontation. It could create a negative impact that you then have to work to overcome, whereas a more neutral color like brown or blue can help neutralize and disperse hostility. Of course we are talking subtleties in both cases, but subtle influences can be important.”


How about the famously red uniform of the Royal Canadian Mounted Police? “Yes, that was used to advantage, especially in the RCMP’s dealings with North American Indian populations,” says Lewinski. “But the RCMP also had a reputation for being compassionate and concerned about the Indians. This earned them a tremendous amount of respect and was able to neutralize the red.”


The RCMP finally got rid of the red uniform for day-to-day duty assignments, Lewinski recalls, because it was considered “too high profile.”


The study of Olympian athletes is reported in the May 19, 2005 issue of the journal Nature.


Recommended for you

Join the discussion

Copyright © 2017 PoliceOne.com. All rights reserved.