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Here are some recently
completed papers and papers in progress. Abstracts appear
below. Each title is a link to the full text where available.
EXTERNAL BALLISTICS
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Acoustic methods for measuring bullet velocity, M Courtney, in press, Applied Acoustics (2007), doi:10.1016/j.apacoust.2007.05.004.
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The truth about ballistic coefficients , M Courtney, A Courtney, (2007).
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An acoustic method for determining ballistic coefficients , M Courtney, A Courtney, (2007).
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Using sound of target impact for acoustic reconstructions of shooting events
, M Courtney, A Courtney, (2006).
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TERMINAL BALLISTICS
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Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities, A Courtney, M Courtney, in press (2007).
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Review of criticisms of ballistic pressure wave experiments, the Strasbourg goat tests, and the Marshall and Sanow data, M Courtney, A Courtney, (2007).
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Ballistic pressure wave contributions to rapid incapacitation in the Strasbourg goat tests, M Courtney, A Courtney, (2007)
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Relative incapacitation contributions of pressure wave and wound channel in the Marshall and Sanow data set
, M Courtney, A Courtney, (2007).
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A method for testing handgun bullets in deer, M Courtney, A Courtney, (2007).
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EXTERNAL BALLISTICS
Acoustic methods for measuring bullet velocity,
M Courtney, in press, Applied Acoustics (2007), doi:10.1016/j.apacoust.2007.05.004.
Key
Words: bullet velocity
This article describes
two acoustic methods to measure bullet velocity with an accuracy of
1% or better. In one method, a microphone is placed within
0.1m of the gun muzzle and a bullet is fired at a steel target 45m
away. The bullet's flight time is the recorded time between
the muzzle blast and sound of hitting the target minus the time for
the sound to return from the target to the microphone. In the
other method, the microphone is placed equidistant from both the gun
muzzle and the steel target 91m away. The time of flight is
the recorded time between the muzzle blast and the sound of the
bullet hitting the target. In both cases, the average bullet
velocity is simply the flight distance divided by the flight time.
The truth about ballistic coefficients , M Courtney, A Courtney, (2007).
Key Words:
acoustic, ballistic coefficient, chronograph, reconstruction
The ballistic coefficient of a bullet describes how it slows in flight due to air resistance. This article presents experimental determinations of ballistic coefficients showing that the majority of bullets tested have their previously published ballistic coefficients exaggerated from 5-25% by the bullet manufacturers. These exaggerated ballistic coefficients lead to inaccurate predictions of long range bullet drop, retained energy and wind drift.
.An acoustic method for determining ballistic coefficients , M Courtney, A Courtney, (2007).
Key Words: bullet, velocity, soundcard, acoustic
Abstract: This paper presents a method for using a PC soundcard, microphone and a chronograph to determine bullet BC with an accuracy of 6%. This is useful when a second chronograph is unavailable or when the projectile accuracy is insufficient to use a far chronograph.
Using sound of target impact for acoustic reconstructions of shooting events , M Courtney, A Courtney, (2006).
Key Words: acoustic, reconstruction, shooting
Abstract
The sound of a bullet hitting a target is sometimes discernable in an audio recording of a shooting event and can be used to determine the distance from shooter to target. This paper provides an example where the microphone is adjacent to the shooter and presents the simple math needed in cases where the microphone is adjacent to the target.
TERMINAL BALLISTICS
Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities,
A Courtney, M Courtney, in press (2007).
Abstract: Identifying patients at
risk of traumatic brain injury (TBI) is important because research
suggests prophylactic treatments to reduce risk of long-term
sequelae. This review considers results from the lateral fluid
percussion model of TBI, ballistic experiments in animal models, and
analyses of human studies. Taken together, these results
support the hypothesis that bullet impacts distant from the brain
produce pressure waves that travel to the brain and can retain
sufficient magnitude to induce brain injury. The link to
long-term sequelae could be investigated via epidemiological studies
of patients who were gunshot in the chest to determine whether they
experience elevated rates of epilepsy and other neurological
sequelae.
Review of criticisms of ballistic
pressure wave experiments, the Strasbourg goat tests, and the
Marshall and Sanow data, M Courtney, A Courtney, (2007).
Abstract This article reviews published criticisms of several ballistic pressure wave experiments authored by Suneson et al., the Marshall and Sanow "one shot stop" data set, and the Strasbourg goat tests. These published criticisms contain numerous logical and rhetorical fallacies, are generally exaggerated, and fail to convincingly support the overly broad conclusions they contain.
Ballistic pressure wave contributions to rapid incapacitation in the Strasbourg goat tests, M Courtney, A Courtney, (2007).
Abstract This article presents empirical models for the relationship between peak ballistic pressure wave magnitude and incapacitation times in the Strasbourg goat test data. Using a model with the expected limiting behavior at large and small pressure wave magnitudes, the average incapacitation times are highly correlated (R = 0.91) with peak pressure wave magnitude. The cumulative incapacitation probability as a function of time reveals both fast (t < 5 s) and slow (t > 5 s) incapacitation mechanisms. The fast incapacitation mechanism can be accurately modeled as a function of peak pressure wave magnitude. The slow incapacitation mechanism is presumably due to blood loss via damaged vascular tissue.
Relative incapacitation contributions of pressure wave and wound channel in the Marshall and Sanow data set , M Courtney, A Courtney, (2007).
Abstract The Marshall and Sanow data set is the largest and most comprehensive data set available quantifying handgun bullet effectiveness in humans. This article presents an empirical model for relative incapacitation probability in humans hit in the thoracic cavity by handgun bullets. The model is constructed by employing the hypothesis that the wound channel and ballistic pressure wave effects each have an associated independent probability of incapacitation. Combining models for these two independent probabilities using the elementary rules of probability and performing a least-squares fit to the Marshall and Sanow data provides an empirical model with only two adjustable parameters for modeling bullet effectiveness with a standard error of 5.6% and a correlation coefficient R = 0.939. This supports the hypothesis that wound channel and pressure wave effects are independent (within the experimental error), and it also allows assignment of the relative contribution of each effect for a given handgun load. This model also gives the expected limiting behavior in the cases of very small and very large variables (wound channel and pressure wave), as well as for incapacitation by rifle and shotgun projectiles.
A method for testing handgun bullets in deer, M Courtney, A Courtney, (2007).
Abstract:
Using service handguns to test bullets in deer is problematic
because of velocity loss with range and accuracy issues giving
sub-optimal shot placement. An alternate method is presented using
a scoped muzzleloader shooting saboted handgun bullets to allow
precise (2” in many cases) shot placement for studying terminal
ballistics in a living target. Deer are baited to a known range and
path obstructions are used to place the deer broadside to the
shooter. Muzzleloading powder charges provide a combination of
muzzle velocity and velocity loss due to air resistance for a given
ballistic coefficient that produce impact velocity corresponding to
typical pistol velocities. With readily available sabots, this
approach allows for testing of terminal ballistics of .355, .357,
.40, .429, .45, and .458 caliber bullets with two muzzleloaders (.45
and .50 caliber).
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