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    8 Comments for this article
    Type of weapon matters
    Frederick Rivara, MD, MPH | University of Washington
    With 14,000 homicides annually from guns, further information on these injuries that might decrease the toll of gun violence is critically important. While the exact location of the GSW is critically important, this study shows that overall the caliber of the bullet also greatly matters.
    CONFLICT OF INTEREST: Editor in Chief, JAMA Network Open
    Difficult to disentangle caliber from multiple hits
    James Cawood, Ph.D. | Factor One, Inc.
    Interesting work. It struck me that since the analysis showed that the fatal cases in this sample involved roughly twice as many wounds on average as the non-fatal cases, the likely additional traumatic and ballistic effects (e.g. blood loss, vital tissue damage, etc.) of those additional wounds raises a significant question concerning what effect the increased caliber had versus the additional effects of the increased number of wounds.
    Caliber - Fatal Validity Flaw
    Douglas Goar, PhD | Retired
    The 7.62 x 39 mm caliber is actually a .30 caliber bullet and by the authors' definition should be grouped into the “small caliber” group. This error is a flaw in the validity of your study. It should also be noted that the 7.62 x 39 mm round is a rifle round. It has a much higher muzzle velocity, generally 2 to 3 time that of handgun rounds. Lethality of a round for the most part must include the caliber and muzzle velocity and then remaining energy at distance to the intended target. For example, the Fort Hood shooter used a FN 5.7 handgun which is a .22 caliber round but with a very high muzzle velocity in the neighborhood of 2000 FPS. The lethality of that attack is well documented.

    Definitions of "Caliber" and Firearm Type Problematic
    Dave A. Olsen | None
    It appears the authors are trying to get at some measure of overall measure of a cartridge to determine lethality.

    They conflate caliber (diameter of the projectile), powder charge, type of gun action (revolver vs semi auto) and other things.

    For example, a .38 and .357 magnum fire the same projectile (caliber) but use different powder charges. Same with .40 and 10mm caliber firearms.

    A .44 magnum is fired from a revolver, .40 and .10 mm from a semi automatic.

    The .30 caliber rifle is smaller caliber but the same bullet weight as the
    .38 and 9 mm bullets and fired from a longer barrel.

    The study does not mention the type of projectile, design, weight, material, shape, and other factors that any hunter would know has a bearing on effectiveness for different uses.

    So, you could arrange the data to show other outcomes.

    The smaller 9mm is more lethal than .40 caliber.
    Revolvers are more lethal than semi automatics (depending on what action the .45 caliber guns used).

    AR15 rifles and their most common cartridge using a .22 caliber bullet are not used for homicides.

    And this only scratches the surface of ballistics, retained energy, sectional density, bullet construction, weight of the gun and its effects on precision, sights, etc. that have an effect on potential lethality.

    Also not mentioned was the number of homicides prevented by the use of firearms by potential victims. Does unholstering a .44 magnum cause crooks to flee more than showing a .22 derringer?

    CONFLICT OF INTEREST: Firearm enthusiast
    Caliber Also Affects Accuracy
    Adam Peterson | None
    The power of the cartridge has a dramatic effect on the accuracy of the firearm. It is much much harder to place an accurate follow-up shot with a more powerful handgun. Clearly a hit with a powerful bullet will be more deadly than a hit with a weaker one, however you can make more hits with a weaker bullet. The data on the number of shots taken compared to hits isn't as available or as accurate as the data on number and placement of wounds but one currently has an effect on the other and that should have been explored. />
    Nothing Really New
    John Santry, B.A. | Law Enforcement
    The notion that caliber plays a roll in terminal ballistics has been known for decades. For example, the FBI has known since the late 1980s that bullet performance is critical to stopping a threat. These were lessons learned following the disastrous Miami shootout, and these costly lessons are why American law enforcement officers don't carry .22 caliber pistols. Although, according to the FBI, within the common law enforcement calibers (9mm, 40 Auto, 45 Auto), the most critical factor is penetration, not necessarily bullet diameter. Of course, success in the law enforcement world is measured in stopping a threat, not death. In our world, a bullet wound can stop a threat without causing death and still be considered 100% effective. The problem here is that small calibers (and - by the way - I disagree with how calibers were categorized in this study) do not STOP as well as larger calibers due to a number of factors including the common lack of adequate penetration by small caliber projectiles. I also wish the study included a specific breakdown of wound location by caliber since location is such a critical factor. The element of time is also missing. In other words, how long did it take for first responders to arrive? How long was it before the victim arrived at a trauma center? How much time elapsed between the wound and death? These are all critical questions.

    "Guns don't kill people" refers only to the fact that guns don't have will or intent. The notion that there is any more meaning than that is just silly.

    Finally - although it was probably statistically insignificant - why on earth did the study include 7.62 X 39mm?

    "Most gunshot victims and survivors were young minority men with prior court arraignments."
    Peter Proctor | http://www.drproctor.com
    The preponderance (94%+) of young minority males as both victims and their killers and the apparent connection with both gang activity and the drug trade is in accord with previous findings, including the claims of antigun advocate Michael Bloomberg. By dint of age, criminal record, and engagement in a criminal enterprise, most, perhaps all, cannot legally own firearms.

    Consequently, most of these individuals have very little firearms training and experience. Police tend to frequent gun ranges and there is a paucity of public lands around Boston
    where shooting is legal. Thus, other variables such as bullet caliber come to the fore.

    An old saw among sportsmen is that "Guns don't kill people, proper stance, grip, aim, trigger pull, and follow-through kill people". That is, training counts. Allegedly, gangs on, e.g., the West coast with greater access to private transportation practice gun handling out in the countryside, typically on public lands far away from the public or law-enforcement, and are thus often quite proficient. Such material differences in training may account for much of the variability of the data.
    Complex Topic
    Ross Boyce, MD, MSc | University of North Carolina at Chapel Hill
    Prior to medical school, I served five years as an infantry officer in the United States Army, service that included a deployment to eastern Baghdad in 2004-05 as a Reconnaissance Platoon Leader. Therefore, I imagine I am one of the few physicians who has seen the tragic impact of firearm injuries in our emergency rooms and medical wards, but who has also used a firearm to take the life of another human being in combat. Those seemingly antithetical experiences, rather than any formal research, inform my comments below.

    First, allow me to commend the authors (and the editors) for
    tackling such an urgent, yet divisive issue. However, the fact that our society is so polarized on its approach to gun violence suggests that the two sides don't even agree on basic facts and/or use common language. My concern is that some aspects of this article, especially reference to the very different types of firearms studied, could exacerbate, rather than bridge that divide. After reading the article, I suspect that those advocating for wider availability of guns will dismiss the authors as "naive."

    For example, the discussion of caliber is inconsistent (as pointed out by previous commentors) not only in the classifications, but also in the units used. Caliber is simply the internal diameter of the barrel, which is traditionally measured in hundredths of an inch. Hence a "50 caliber" bullet has a diameter of 0.5 inches or 12.7 mm. Therefore, it is not clear to me how the authors decided on their classification scheme in which a 0.357 magnum (ie 9.06 mm) is coded as "large," yet a 0.38 caliber (9.65 mm) is coded as medium. Similarly, a 7.62 x 39 mm (0.3 caliber) is coded as large, while a 0.32 caliber (8.13 mm) is coded as small. It seems as if the authors are making other assessments about the power (i.e. kinetic energy, muzzle velocity, etc) of the round. I am also surprised that the journal would allow switching back and forth between metric and imperial units so frequently, even if the authors are using common terms.

    Second, I would like to see the analysis either stratified or limited by number of gunshot wounds and wound distribution. For example, I think it would be much more compelling if the authors were able to demonstrate that among individuals who received a single gunshot wound to the chest, those who were shot with larger caliber bullets died more frequently, although I suspect the study is not powered appropriately for outcomes such as this.

    Lastly, I think it would be a mistake to focus on the caliber result, rather than other findings, such as the high proportion of events associated with gang violence and victims of color (ie wealth inequalities, historical discrimination), the much stronger association between fatal outcomes and multiple wounds (ie high capacity weapons), and the overwhelming number of events associated with handguns/pistols as opposed to rifles (ie ability to conceal, transport, etc). These findings seem just as, if not more important, from a policy perspective than any association with caliber.
    Original Investigation
    Public Health
    July 27, 2018

    The Association of Firearm Caliber With Likelihood of Death From Gunshot Injury in Criminal Assaults

    Author Affiliations
    • 1School of Criminology and Criminal Justice, Northeastern University, Boston, Massachusetts
    • 2Sanford Institute of Public Policy, Duke University, Durham, North Carolina
    JAMA Netw Open. 2018;1(3):e180833. doi:10.1001/jamanetworkopen.2018.0833
    Key Points español 中文 (chinese)

    Question  Is there an association between the likelihood of death for firearms shooting victims and the caliber of the firearm?

    Findings  A cross-sectional study using 5 years of data extracted from investigation files kept by the Boston Police Department determined that the case-fatality rates of assaults inflicting gunshot injury increased significantly with the caliber of the firearm. Caliber was not significantly correlated with other observable characteristics of the assault, including indicators of intent and determination to kill.

    Meaning  The findings are foundational to the debate over whether deadly weapons should be better regulated and provide evidence against the common view that whether the victim lives or dies is determined largely by the assailant’s intent and not the type of weapon.


    Importance  A foundational issue in firearms policy has been whether the type of weapon used in an assault affects the likelihood of death.

    Objective  To determine whether the likelihood of death from gunshot wounds inflicted in criminal assaults is associated with the power of the assailant’s firearm as indicated by its caliber.

    Design, Setting, and Participants  Cross-sectional study with multivariate analysis of data on shooting cases extracted by the authors from police investigation files for assaults that took place in Boston, Massachusetts, between January 1, 2010, and December 31, 2014. These data were analyzed between October 1, 2017, and February 18, 2018. In all cases the victim sustained 1 or more gunshot wounds in circumstances that the Boston Police Department deemed criminal. The working sample included all 221 gun homicides and a stratified random sample of 300 nonfatal cases drawn from the 1012 that occurred during the 5-year period. Seven nonfatal cases were omitted because they had been misclassified.

    Exposures  The primary source of variation was the caliber of the firearm used to shoot the victim.

    Main Outcomes and Measures  Whether the victim died from the gunshot wound(s).

    Results  The final sample of 511 gunshot victims and survivors (n = 220 fatal; n = 291 nonfatal) was predominantly male (n = 470 [92.2%]), black (n = 413 [80.8%]) or Hispanic (n = 69 [13.5%]), and young (mean [SD] age, 26.8 [9.4] years). Police investigations determined firearm caliber in 184 nonfatal cases (63.2%) and 183 fatal cases (83.2%). These 367 cases were divided into 3 groups by caliber: small (.22, .25, and .32), medium (.38, .380, and 9 mm), or large (.357 magnum, .40, .44 magnum, .45, 10 mm, and 7.62 × 39 mm). Firearm caliber had no systematic association with the number of wounds, the location of wounds, circumstances of the assault, or victim characteristics, as demonstrated by χ2 tests of each cluster of variables and by a comprehensive multinomial logit analysis. A logit analysis of the likelihood of death found that compared with small-caliber cases, medium caliber had an odds ratio of 2.25 (95% CI, 1.37-3.70; P = .001) and large caliber had an odds ratio of 4.54 (95% CI, 2.37-8.70; P < .001). Based on a simulation using the logit equation, replacing the medium- and large-caliber guns with small-caliber guns would have reduced gun homicides by 39.5%.

    Conclusions and Relevance  Firearms caliber was associated with the likelihood of death from gunshot wounds in criminal assault. Shootings with larger-caliber handguns were more deadly but no more sustained or accurate than shootings with smaller-caliber handguns. This conclusion is of direct relevance to the design of gun policy.