Dr. Heather Shaw MD, the chief of radiology, at the hospital that received the victims of the mass shooter in Parkland wrote this in Atlantic.
"As I opened the CT scan last week to read the next case, I was baffled. The history simply read 'gunshot wound.' I have been a radiologist in one of the busiest trauma centers in the nation for 13 years, and have diagnosed thousands of handgun injuries to the brain, lung, liver, spleen, bowel, and other vital organs. I thought that I knew all that I needed to know about gunshot wounds, but the specific pattern of injury on my computer screen was one that I had seen only once before.
"In a typical handgun injury that I diagnose almost daily, a bullet leaves a laceration through an organ like the liver. To a radiologist, it appears as a linear, thin, grey bullet track through the organ. There may be bleeding and some bullet fragments.
"I was looking at a CT scan of one of the victims of the shooting at Marjory Stoneman Douglas High School, who had been brought to the trauma center during my call shift. The organ looked like an overripe melon smashed by a sledgehammer, with extensive bleeding. How could a gunshot wound have caused this much damage?
"The reaction in the emergency room was the same. One of the trauma surgeons opened a young victim in the operating room, and found only shreds of the organ that had been hit by a bullet from an AR-15, a semi-automatic rifle which delivers a devastatingly lethal, high-velocity bullet to the victim. There was nothing left to repair, and utterly, devastatingly, nothing that could be done to fix the problem. The injury was fatal. And that experience repeated time after time.
Compare the damage an AR-15 and a 9mm handgun can do to the human body: “One looks like a grenade went off in there,” says Peter Rhee, a trauma surgeon at the University of Arizona. “The other looks like a bad knife cut.”
The 9mm handgun is generally regarded as an effective weapon; its bullet travels at 1,200 feet per second and delivers a kinetic energy punch of 400 foot pounds. By comparison, the standard AR-15 bullet travels at 3,251 feet per second and delivers 1300 foot pounds. 3 times the velocity and 4 times the punch.
The AR-15 is America’s most popular rifle. It has also been the weapon of choice in mass shootings from Sandy Hook to Aurora to San Bernardino to Parkland. The carnage sparked new calls to reinstate a ban on assault rifles like the AR-15, which were designed as weapons of war, intended to replace the M-16 in Vietnam.
It’s possible to argue about everything when it comes to the politics of guns—including about the definition of “assault rifle” itself—but it’s harder to argue about physics. So let's consider the physics of an AR-15.
A bullet with more energy can do more damage. Its total kinetic energy is equal to one-half the mass of the bullet times its velocity squared. The bullet from a handgun is—as absurd as it may sound—slow compared to that from an AR-15. It can be stopped by the thick bone of the upper leg. It is often passed through the body only to be stopped at a single organ where the damage is significant but narrow. These bullets can even become lodged in skin especially if the skin is backed by cartilage, muscle or bone.
The bullet from an AR-15 does an entirely different kind of violence to the human body. It’s relatively small, but it leaves the muzzle at three times the speed of a handgun bullet. It has so much energy that it can disintegrate three inches of leg bone. “It would just turn it to dust,” says Donald Jenkins, a trauma surgeon at University of Texas Health Science Center at San Antonio. If it hits the liver, “the liver looks like a jello mold that’s been dropped on the floor.” And the exit wound can be a nasty, jagged hole the size of an orange.
These high-velocity bullets can damage flesh inches away from their path, either because they fragment or because they cause something called cavitation. When you trail your fingers through water, the water ripples and curls. When a high-velocity bullet pierces the body, human tissues ripples as well—but much more violently. The bullet from an AR-15 might miss the femoral artery in the leg, but cavitation may burst the artery anyway, causing death by blood loss. A swath of stretched and torn tissue around the wound may die. That’s why, says Rhee, a handgun wound usually requires only one surgery to deal with immediate damage saving life and limb but an AR-15 bullet wound that is operable often requires three to ten.
Then, multiply the damage from a single bullet by the ease of shooting an AR-15, which doesn’t kick making multiple shots easy. “The gun barely moves. You can sit there boom boom boom and reel off shots as fast as you can move your finger,” says Ernest Moore, a trauma surgeon at Denver Health and editor of the Journal of Trauma and Acute Surgery, which just published an issue dedicated to gun violence.
Handguns kill plenty of people too, of course, and they’re responsible for the vast majority of America’s gun deaths (the majority the result of suicide). But a single bullet from a handgun is not likely to be as deadly as one from an AR-15.
Routine handgun injuries leave entry and exit wounds and linear tracks through the victim's body that are roughly the size of the bullet. If the bullet does not directly hit something crucial like the heart or the aorta, and they do not bleed to death before being transported to our care at a trauma center, chances are, ER's can save the victim. The bullets fired by an AR-15 are different; they travel at higher velocity and are far more lethal. The damage they cause is a function of the energy they impart as they pass through the body. A typical AR-15 bullet leaves the barrel traveling almost three times faster than, and imparting more than three times the energy of, a typical 9mm bullet from a handgun. An AR-15 rifle outfitted with a magazine with 50 rounds allows many more lethal bullets to be delivered quickly without reloading. Trauma studies show that a bullet from such a weapon is 11 times more likely to result in death than one from a handgun.
Furthermore with an AR-15, the shooter does not have to be particularly accurate. The victim does not have to be unlucky. If a victim takes a direct hit to the liver from an AR-15, the damage is far graver than that of a simple handgun shot injury. Handgun injuries to the liver are generally survivable unless the bullet hits the main blood supply to the liver. An AR-15 bullet wound to the middle of the liver would cause so much bleeding that the patient would likely never make it to a trauma center to receive our care.
In Parkland while the shooting was still in progress, the first responders were gathering up victims whenever they could and carrying them outside the building. Even the physicians trained in trauma situations could do nothing at the scene to help to save the victims who had been shot with the AR-15. Most of them died on the spot, with no fighting chance at life.
A peripheral wound from a bullet fired by an AR-15.
Comparing the damage from two bullets from two guns.......