Who wrote the article should have no bearing on an objective response .
And the doctor is specifically talking about the bullet if you actually read the whole article --
"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, we 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."
"I have seen a handful of AR-15 injuries in my career. I saw one from a man shot in the back by a SWAT team years ago. The injury along the path of the bullet from an AR-15 is vastly different from a low-velocity handgun injury. The bullet from an AR-15 passes through the body like a cigarette boat travelling at maximum speed through a tiny canal. The tissue next to the bullet is elastic?moving away from the bullet like waves of water displaced by the boat?and then returns and settles back. This process is called cavitation; it leaves the displaced tissue damaged or killed. The high-velocity bullet causes a swath of tissue damage that extends several inches from its path. It does not have to actually hit an artery to damage it and cause catastrophic bleeding. Exit wounds can be the size of an orange."
And the doctor is specifically talking about the bullet if you actually read the whole article --
"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, we 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."
"I have seen a handful of AR-15 injuries in my career. I saw one from a man shot in the back by a SWAT team years ago. The injury along the path of the bullet from an AR-15 is vastly different from a low-velocity handgun injury. The bullet from an AR-15 passes through the body like a cigarette boat travelling at maximum speed through a tiny canal. The tissue next to the bullet is elastic?moving away from the bullet like waves of water displaced by the boat?and then returns and settles back. This process is called cavitation; it leaves the displaced tissue damaged or killed. The high-velocity bullet causes a swath of tissue damage that extends several inches from its path. It does not have to actually hit an artery to damage it and cause catastrophic bleeding. Exit wounds can be the size of an orange."