Force Science News #165:

New report underscores credibility of Force Science’s shell-ejection studies

Contrary to persistent myth, where a cartridge case lands when it’s ejected from a semiautomatic pistol is not a reliable indicator of where the shooter was standing when the gun was fired.


That fact has been scientifically confirmed by the Force Science Institute in a series of research experiments starting back in 2004. “Yet some investigators and firearms experts continue to use the location of spent casings as critical reference points in reconstructing shooting scenes,” says FSI’s executive director, Dr. Bill Lewinski.


“In the most tragic instances, this spurious ‘evidence’ has been cited in court to challenge officers’ statements about where they were positioned in controversial officer-involved shootings. And when such testimony is accepted as dependable, officers can suffer grave injustices.”


[One example of a trial in which cartridge-case placement became a pivotal issue involved Arizona officer Dan Lovelace, whose courtroom ordeal, firing, and painful aftermath were covered in Force Science News transmissions #1 and #129 (Click here to go to the FS News Archive) This case is also thoroughly critiqued in the Institute’s course for certification in Force Science Analysis.]


Now it will be easier for conscientious investigators, expert witnesses, and police attorneys to refute outmoded concepts about the importance of shell placement. Force Science findings on this subject have recently been given enhanced credibility with the publication of a peer-reviewed report on the Institute’s unique work in an academic journal, validating that the research methods employed were sound.


In a detailed article titled “Fired Cartridge Case Ejection Patterns from Semi-automatic Firearms,” authored by a research team led by Lewinski, the current issue of Investigative Sciences Journal showcases the emphatic results from one of FSI’s studies, involving more than 7,600 rounds cycled through the 8 pistol models most commonly carried by LEOs. [Click here for the full article.]


These tests, the report states, “highlighted significant inconsistencies of spent cartridge-case ejection, compared to what is commonly expected and accepted.


The Journal is edited by Dr. James Adcock of the University of South Carolina and Dr. Henry Lee of the University of New Haven, with an editorial board of scholars from other institutions of higher learning in the U.S. and the United Kingdom. FSI’s research, Adcock states in an editor’s preface, “will be extremely helpful to those tasked with reconstructing shooting incidents.”


LASD STUDY. The featured study was conducted in California at a range operated in “a small sheltered valley” by the Los Angeles County Sheriff’s Dept. Forty-five deputy volunteers participated. They ranged in age from 22 to 50 and had from 2 months’ to 28 years’ LE experience.


Collectively, they fired 7,670 Winchester or Federal rounds from 9mm, .40-cal., and .45-cal handgun models: S&W 5906, Glock 17, Glock 21, Glock 23, Sig Sauer 226, Sig Sauer 229, H&K USP, and Beretta 92FS. These pistols are all designed to eject empty cases to the right rear.


Each deputy fired multiple rounds with gun held in 11 different positions. These covered a broad range of postures and manipulations: 1- and 2-handed grips at eye and waist levels while standing still and while turning; an awkward, improper 2-handed hold that an officer might unintentionally achieve in rushing to get on target; inward, angled cants that sometimes occur when rotating and shooting; muzzle angled downward at a 22-degree angle and upward at 45 degrees; and so on.


All positions and movements studied have been “performed by police officers in dynamic, rapidly unfolding life-and-death shooting situations,” as discerned from investigations of OISs across 30 years, Lewinski says.


When shooting, each deputy stood by a stake in the center of a 30-ft. x 30-ft. test site, which was covered to a depth of 3 inches with carefully leveled, fine-grain river sand. “This reduced the bounce factor of the ejected cases to nearly zero,” Lewinski explains.


The 900-sq.-ft. area was gridded with colored string into 1-ft. square sections. To further pinpoint where ejected cases landed, researchers used transparent plastic templates with 1-in. grid marks that could be inserted into any square where cartridges fell.


The weather was “hot and still each testing day, so wind was not a significant factor in the test results,” Lewinski says. An earthen bluff served as a backstop for the shooting.


FINDINGS. “The results of this study demonstrated how unpredictable spent cartridge casing ejection patterns are,” the Journal report declares. The researchers documented “significant variability and uncertainty” about where a spent case “would come to rest” when ejected, the report says, emphasizing “the imprecision of identifying shooter location based solely on the location of a spent cartridge casing.”


For tabulation purposes, the gridded test area was divided into 4 quadrants that pin-wheeled around the shooter’s stake: right front and rear, and left front and rear. Lumping all test positions and firearms together, 73.6 percent of the spent cases fell into the quadrant right and rear of the shooter’s position.


“This confirms what experts cite as the location that spent cartridge casings should land in when ejected from the firearms used in this study,” the researchers note.


However, they point out, this means that over 2,000 casings—a significant 26.4 percent of those fired during the study—landed outside the anticipated “correct” area. Indeed, consistent with previous Force Science studies, cases fell within the entire 360 degrees—all 4 quadrants—surrounding the shooting position. The final resting places of some cases were more than 20 feet apart. And even those that settled within the right-rear quadrant were scattered widely within that area’s 225-sq.-ft. dimensions.


“This illustrates how using the placement of a single spent cartridge casing to determine shooter location is not as precise as it may seem,” the researchers write. At best, casing location can “lead to only a tentative estimate of the shooter’s location.”


The posture that most often produced the traditionally expected right-rear result was the idealized training position: the “proper” 2-handed grip with arms extended and weapon uncanted and horizontal to the ground at eye level. When shots were fired from that position with the shooter stationary, ejected cases ended up in the right-rear quadrant 97 percent of the time. Even then, however, at least some rounds still landed in each of the other quadrants around the shooter.


Other positions produced more marked variances from the “norm.” For example, when a pistol was held down at a 22-degree angle and cantilevered in, as might easily occur during dynamic movement in a gunfight, less than 30 percent of expended casings landed to the right and rear of the shooter. The heaviest concentration (nearly 44 percent) ended up in the left-rear quadrant in that posture. Some 18 percent landed in the right-front.


“Changing the firearm position drastically changed the spent cartridge-casing pattern,” Lewinski says.


CONCLUSIONS. Data from the study were exhaustively analyzed, determining ejection results according to ammunition and make and model of weapon, as well as by stance and movement. Full details were too exhaustive to be included in the Journal report, but Lewinski states that “the only consistency is the inconsistency of where spent shells landed, whatever variable was under scrutiny.


“Unlike the relatively calm and precise gun-handling of range shooting, which results often in patterns as they are expected to occur, a real-life gunfight is almost certain to be complex, rapidly unfolding, time-pressured, and life-threatening, with very different grips, stances, movements, and angles of weapon deployment brought into play,” Lewinski says.


“Each person holds and fires a gun in his or her own idiosyncratic fashion under those conditions. The variables of human dynamics are usually unknown after the fact. Yet they impact profoundly on cartridge-case placement.


“In shooting investigations, it is imperative to obtain the most accurate shooter location that can be determined from the evidence. A shooter’s location can be vital in understanding how an encounter evolved. But investigators and others attempting to reconstruct a shooting event must understand that relying solely on where a spent shell is found to determine a shooter’s firing position can be a severely flawed method.


“Hopefully the publication of this study in a peer-reviewed journal will help in burying that dangerous mythology for good.”


Besides Lewinski, the research team authoring the new report includes Force Science Advisor Dr. William Hudson; David Karwoski, formerly on the law enforcement faculty at Minnesota State University-Mankato now serving as a leadership advisor to the Iraq government; and Force Science Research Assistant Christa Redmann.


To read other articles of interest, including fascinating case histories, you can access past issues of Investigative Sciences Journal free of charge at: [].



FSN Extras


I. Our readers write…


II. European police trainers seek information on Force Science findings


III. New “Excellence in Training” e-book aids ILEETA scholarship fund


I. Our readers write…


In Force Science News Transmission #163 [“Anger sets the stage for seeing threats where none exist”], we reported on Northeastern University research indicating that test subjects who are angry are more likely to mistake an innocent object in an individual’s hand for a gun than those experiencing less hostile emotions. Reader responses include:


Misidentification easier when the stakes are very high


I think Dr. Lewinski raises some very valid cautions about how much we can infer from this study. In the real world, the stakes for a misidentification can be very high: having an armed suspect shoot the officer, or someone else, or the officer shooting someone who doesn’t have a firearm. The stress this creates can be a significant factor in making correct identification more difficult.


I’m reminded of an old Alfred Hitchcock TV episode in which an older man sees a younger one with a new cigarette lighter and offers him a wager. If the man with the lighter can get it to light 10 times in a row, the older man will give him a new car. If not, the older man will cut off the younger man’s little finger. The younger man confidently takes the bet.


I won’t spoil the outcome if you haven’t seen it, but it highlights the point that a very simple action is a lot more stressful and hard to do when the risks involved are great.


Atty. Adam Kasanof


Lt., NYPD (ret.)


Arlington, VA


Was the study really free of bias?


The researchers attempted to diminish the risk of bias by showing test pictures only of individuals of “apparent white European ancestry” for rapid evaluation. If all of the participants whose reactions were recorded were also white people of apparent European descent, then there would likely be no problem. But if some of the participants were people who might feel a bias toward white people of apparent European descent, for whatever personal reasons, then the results may be skewed.


My life experience indicates that it might have been better to match the “target individuals” to the participants based on apparent ethnic origin and gender in order to obtain a more balanced result. But I’m just a cop.


Spcl. Agt. Frank Mulkearns


Firearms/force instructor, DHS/ICE


Burke, VA



Does some training breed anger?


I have wondered if we actually create “anger” in police officers during basic training through the use of some forms of discipline and poorly planned and executed scenarios. Could this anger actually be anxiety that has been programmed into recruits through training? I don’t suggest this is the only answer, but it may be a component.


As for good training, I recently spent a week with [Force Science technical advisor] Ken Murray at a reality-based training instructor course. We have been able to contract with Ken for the past 3 years and have trained over 240 firearms and DT instructors. Our goal is to institutionalize RBT throughout the state. This training has had a significant impact on the mind-set of the instructors.


Mark Fettinger


Supervisor of Public Safety Programs


State Div. of Criminal Justice Services


Albany, NY


“Great addition” to leadership training


In our Academy of Police Supervision (a 3- week, residential, 1st-line leadership course), I teach emotional intelligence. This article would be a great addition to my material. Would you mind if I use it? [Permission granted—FSN ed.]


Ken Morris


State Dept. of Criminal Justice Training


Richmond, KY



II. European police trainers seek information on Force Science findings


Dr. Bill Lewinski, executive director of the Force Science Institute, has been invited to address the annual European Police Trainer Conference next March 10-11 in Nuremberg, Germany, regarding his research on deadly force dynamics.


The conference is sponsored by PID (Polizeitrainer in Deutschland), a non-profit research group organized in 1996 by German officers to “continually develop and improve the effectiveness and quality of duty-related security and survival training.” Working with experts in Europe and abroad, PID personnel develop, evaluate, and offer training in defensive techniques and tactics for line officers, according to president Eckhard Niebergall.



III. New “Excellence in Training” e-book aids ILEETA scholarship fund


A popular proponent of the winning law enforcement mind-set has published a new book you can download for less than $6—and help police training in the process.


Brian Willis, author of the popular W.I.N. blog column and a certified Force Science Analyst, is offering the e-book Excellence in Training as a fund-raiser for the ILEETA Scholarship Fund. It’s an excellent—and useful—62-page collection of “thoughts, insights, and lessons learned” from Willis’s 30-plus years as a member of the Calgary (Canada) Police Service and as an international instructor with his Winning Mind Training organization.


For immediate download, go to: Cost is only $5.77, of which $4 goes toward ILEETA scholarships.


Written by Force Science Institute

December 16th, 2010 at 2:15 pm

© 2017 Force Science Institute Ltd.