Michael Courtney
Member
Ballistics Testing Group 2008 Publications
We appreciate the thoughtful discussions and valuable references provided by forum members over the years, and we are mindful of the regular requests by forum members to keep them appraised of our ongoing work. We’ve been busy in 2008, as attested by the list of publications below. The emails I’ve been getting also indicate our article on ballistic coefficients has recently been published by Varmint Hunter Magazine, though I have not yet received a copy in confirmation.
A Thoracic Mechanism of Mild Traumatic Brain Injury Due to Blast Pressure Waves
Published as: Medical Hypotheses, Volume 72, Issue 1 (2009) , p 76 – 83. doi:10.1016/j.mehy.2008.08.015
http://arxiv.org/ftp/arxiv/papers/0812/0812.4757.pdf
ABSTRACT
The mechanisms by which blast pressure waves cause mild to moderate traumatic brain injury (mTBI) are an open question. Possibilities include acceleration of the head, direct passage of the blast wave via the cranium, and propagation of the blast wave to the brain via a thoracic mechanism. The hypothesis that the blast pressure wave reaches the brain via a thoracic mechanism is considered in light of ballistic and blast pressure wave research. Ballistic pressure waves, caused by penetrating ballistic projectiles or ballistic impacts to body armor, can only reach the brain via an internal mechanism and have been shown to cause cerebral effects. Similar effects have been documented when a blast pressure wave has been applied to the whole body or focused on the thorax in animal models. While vagotomy reduces apnea and bradycardia due to ballistic or blast pressure waves, it does not eliminate neural damage in the brain, suggesting that the pressure wave directly affects the brain cells via a thoracic mechanism. An experiment is proposed which isolates the thoracic mechanism from cranial mechanisms of mTBI due to blast wave exposure. Results have implications for evaluating risk of mTBI due to blast exposure and for developing effective protection.
Comments on “Ballistics: a primer for the surgeon”
Published as: Injury, 2008 Aug; 39(8): p 964-5. DOI: 10.1016/j.injury.2008.03.020
http://arxiv.org/ftp/arxiv/papers/0812/0812.4930.pdf
Abstract:
In response to a published assertion to the contrary, this paper briefly reviews many studies that document remote wounding effects of ballistic pressure waves including experiments in pigs and dogs that find brain injury resulting from animal models shot in the thigh and case studies in humans that document both remote brain and spinal cord injuries ascribed to ballistic pressure waves.
Apparent measurement errors in “Development of biomechanical response corridors of the thorax to blunt ballistic impacts”
Published as: Journal of Biomechanics, Volume 41, Issue 2, 2008, Page 486
http://arxiv.org/ftp/arxiv/papers/0812/0812.4755.pdf
Abstract: “Development of biomechanical response corridors of the thorax to blunt ballistic impacts” (Bir, C., Viano, D., King, A., 2004, Journal of Biomechanics 37, 73-79.) contains apparent measurement errors. Areas under several force vs. time (Fig. 2) and force vs. deflection curves (Fig.4) differ significantly from the momentum and kinetic energy changes, respectively.
Misleading reference to unpublished wound ballistics data regarding distant injuries
http://arxiv.org/ftp/arxiv/papers/0812/0812.4927.pdf
Abstract: An article (J Trauma 29:10-18, 1989) cites unpublished wound ballistics data to support the authors’ view that distant injuries are a myth in wound ballistics. The actual data, published in 1990, contains a number of detailed examples of distant injuries. (Bellamy RF, Zajtchuk R. The physics and biophysics of wound ballistics. In: Zajtchuk R, ed. Textbook of Military Medicine, Part I: Warfare, Weaponry, and the Casualty, Vol. 5, Conventional Warfare: Ballistic, Blast, and Burn Injuries. Washington, DC: Office of the Surgeon General, Department of the Army, United States of America; 1990: 107-162)
Comments Regarding “On the Nature of Science”
Published as: Physics in Canada, Vol. 64, No. 3 (2008), p7-8.
http://arxiv.org/ftp/arxiv/papers/0812/0812.4932.pdf
Abstract: An attempt to redefine science in the 21st century (BK Jennings, On the Nature of Science, Physics in Canada, 63(7) 2007) has abandoned traditional notions of natural law and objective reality, blurred the distinctions between natural science and natural history, elevated Occam’s razor from an epistemological preference to a scientific principle, and elevated peer-review and experimental care as equals with repeatable experiment as arbiters of scientific validity. Our comments review the long-established axioms of the scientific method, remind readers of the distinctions between science and history, disprove the generality of Occam’s razor by counter example, and highlight the risks of accepting additional scientific arbiters as equal to repeatable experiment.
Acoustic methods for measuring bullet velocity
Published as: Applied Acoustics 69 (2008) 925–928, doi:10.1016/j.apacoust.2007.05.004
http://arxiv.org/ftp/arxiv/papers/0812/0812.4752.pdf
Abstract: 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 0.1 m of the gun muzzle and a bullet is fired at a steel target 45 m 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 91 m 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.
Key words: bullet velocity
A method for testing bullets at reduced velocity
http://arxiv.org/ftp/arxiv/papers/0812/0812.4934.pdf
Abstract: Reconstruction of shooting events occasionally requires testing of bullets at velocities significantly below the typical muzzle velocity of cartridge arms. Trajectory, drag, and terminal performance depend strongly on velocity, and realistic results require accurately reconstructing the velocity. A method is presented for testing bullets at reduced velocities by loading the bullet into a sabot and firing from a muzzleloader with a suitably reduced powder charge. Powder charges can be safely reduced to any desirable level when shooting saboted bullets from a muzzleloader; in contrast, cartridge arms can only be safely operated within a narrow window of powder charges/muzzle velocities. This technique is applicable to a wide range of both pistol and rifle bullets at velocities from 700 ft/s to 2000 ft/s.
We appreciate the thoughtful discussions and valuable references provided by forum members over the years, and we are mindful of the regular requests by forum members to keep them appraised of our ongoing work. We’ve been busy in 2008, as attested by the list of publications below. The emails I’ve been getting also indicate our article on ballistic coefficients has recently been published by Varmint Hunter Magazine, though I have not yet received a copy in confirmation.
A Thoracic Mechanism of Mild Traumatic Brain Injury Due to Blast Pressure Waves
Published as: Medical Hypotheses, Volume 72, Issue 1 (2009) , p 76 – 83. doi:10.1016/j.mehy.2008.08.015
http://arxiv.org/ftp/arxiv/papers/0812/0812.4757.pdf
ABSTRACT
The mechanisms by which blast pressure waves cause mild to moderate traumatic brain injury (mTBI) are an open question. Possibilities include acceleration of the head, direct passage of the blast wave via the cranium, and propagation of the blast wave to the brain via a thoracic mechanism. The hypothesis that the blast pressure wave reaches the brain via a thoracic mechanism is considered in light of ballistic and blast pressure wave research. Ballistic pressure waves, caused by penetrating ballistic projectiles or ballistic impacts to body armor, can only reach the brain via an internal mechanism and have been shown to cause cerebral effects. Similar effects have been documented when a blast pressure wave has been applied to the whole body or focused on the thorax in animal models. While vagotomy reduces apnea and bradycardia due to ballistic or blast pressure waves, it does not eliminate neural damage in the brain, suggesting that the pressure wave directly affects the brain cells via a thoracic mechanism. An experiment is proposed which isolates the thoracic mechanism from cranial mechanisms of mTBI due to blast wave exposure. Results have implications for evaluating risk of mTBI due to blast exposure and for developing effective protection.
Comments on “Ballistics: a primer for the surgeon”
Published as: Injury, 2008 Aug; 39(8): p 964-5. DOI: 10.1016/j.injury.2008.03.020
http://arxiv.org/ftp/arxiv/papers/0812/0812.4930.pdf
Abstract:
In response to a published assertion to the contrary, this paper briefly reviews many studies that document remote wounding effects of ballistic pressure waves including experiments in pigs and dogs that find brain injury resulting from animal models shot in the thigh and case studies in humans that document both remote brain and spinal cord injuries ascribed to ballistic pressure waves.
Apparent measurement errors in “Development of biomechanical response corridors of the thorax to blunt ballistic impacts”
Published as: Journal of Biomechanics, Volume 41, Issue 2, 2008, Page 486
http://arxiv.org/ftp/arxiv/papers/0812/0812.4755.pdf
Abstract: “Development of biomechanical response corridors of the thorax to blunt ballistic impacts” (Bir, C., Viano, D., King, A., 2004, Journal of Biomechanics 37, 73-79.) contains apparent measurement errors. Areas under several force vs. time (Fig. 2) and force vs. deflection curves (Fig.4) differ significantly from the momentum and kinetic energy changes, respectively.
Misleading reference to unpublished wound ballistics data regarding distant injuries
http://arxiv.org/ftp/arxiv/papers/0812/0812.4927.pdf
Abstract: An article (J Trauma 29:10-18, 1989) cites unpublished wound ballistics data to support the authors’ view that distant injuries are a myth in wound ballistics. The actual data, published in 1990, contains a number of detailed examples of distant injuries. (Bellamy RF, Zajtchuk R. The physics and biophysics of wound ballistics. In: Zajtchuk R, ed. Textbook of Military Medicine, Part I: Warfare, Weaponry, and the Casualty, Vol. 5, Conventional Warfare: Ballistic, Blast, and Burn Injuries. Washington, DC: Office of the Surgeon General, Department of the Army, United States of America; 1990: 107-162)
Comments Regarding “On the Nature of Science”
Published as: Physics in Canada, Vol. 64, No. 3 (2008), p7-8.
http://arxiv.org/ftp/arxiv/papers/0812/0812.4932.pdf
Abstract: An attempt to redefine science in the 21st century (BK Jennings, On the Nature of Science, Physics in Canada, 63(7) 2007) has abandoned traditional notions of natural law and objective reality, blurred the distinctions between natural science and natural history, elevated Occam’s razor from an epistemological preference to a scientific principle, and elevated peer-review and experimental care as equals with repeatable experiment as arbiters of scientific validity. Our comments review the long-established axioms of the scientific method, remind readers of the distinctions between science and history, disprove the generality of Occam’s razor by counter example, and highlight the risks of accepting additional scientific arbiters as equal to repeatable experiment.
Acoustic methods for measuring bullet velocity
Published as: Applied Acoustics 69 (2008) 925–928, doi:10.1016/j.apacoust.2007.05.004
http://arxiv.org/ftp/arxiv/papers/0812/0812.4752.pdf
Abstract: 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 0.1 m of the gun muzzle and a bullet is fired at a steel target 45 m 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 91 m 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.
Key words: bullet velocity
A method for testing bullets at reduced velocity
http://arxiv.org/ftp/arxiv/papers/0812/0812.4934.pdf
Abstract: Reconstruction of shooting events occasionally requires testing of bullets at velocities significantly below the typical muzzle velocity of cartridge arms. Trajectory, drag, and terminal performance depend strongly on velocity, and realistic results require accurately reconstructing the velocity. A method is presented for testing bullets at reduced velocities by loading the bullet into a sabot and firing from a muzzleloader with a suitably reduced powder charge. Powder charges can be safely reduced to any desirable level when shooting saboted bullets from a muzzleloader; in contrast, cartridge arms can only be safely operated within a narrow window of powder charges/muzzle velocities. This technique is applicable to a wide range of both pistol and rifle bullets at velocities from 700 ft/s to 2000 ft/s.
