Friday, April 26, 2019

NRA Firearms Law Seminar - Terminal Ballistics

Dr. Paul Maurer gave a great presentation on terminal ballistics - the study of interface between physics and the projectile moving in space and the impact with biologic tissue.

He noted biologic tissue is incredibly random and variable as compared to physics of how the projectile move up until it hits biological tissue.

He has quite a fun sense of humor as a surgeon, he notes forensic pathologists tend to be a day late when assessing a shooting subject. To say he had everyone's attention was an understatement.

He also knows Martin Fackler very well and worked with him in the army.

From a surgeon's perspective he noted much of what people believe about terminal ballistics is myths not science.

Goal is incapacitation in a lethal force encounter.

Incapacitation is achieved by a hit to the Central Nervous System - the brain or spinal cord hit which is a small surface area; or Exsanguination - namely blood loss.

Even a shot to the heart the person can still act for about 3 seconds.

He gave some great case studies on incapacitation.

He notes gelatin is useful to scientifically reproduce results.

He addressed the bigger hole more blood loss noted the 9mm or 45 ACP when you put a hole in the fluid container it does similar damage, and once you hit a certain threshold its all about real estate- location, location, location, and bullet design as there is no perfect answer when dealing with biologic tissue.

You do get a stretch cavity with a handgun bullet, and tissue does become dysfunctional even if later it looks ok at an autopsy. Question becomes where did the stretch cavity go if it causes any significant damage and hits tissue where it is used to stretch like a lung or intestine. Rifles on the other hand bring a lot more energy to the party.

stretch cavity is figured out by the kinetic energy calculation Ke=1/2 mass x velocity squared.

Any projectile penetrating the body 7-8 inches will get to the heart. Nipple to bottom rib on right side is a high fatality injury. When you hit 30% blood loss you're incapacitated. In short if you do your job with shot placement, the bullet will do its job.

Absolutely outstanding presentation.

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