Why an AR-15 is so lethal: bullets fired at very high speed

Screenshot of Post 3-D animation of AR-15 bullet impact*

What does the average American know about the AR-15? It's powerful? Controversial? It's both, but why? It's about the automatic rifle's bullets and their speed.

"The AR-15 fires bullets at such a high velocity — often in a barrage of 30 or even 100 in rapid succession — that it can eviscerate multiple people in seconds. A single bullet lands with a shock wave intense enough to blow apart a skull and demolish vital organs," report N. Kirkpatrick, Atthar Mirza, and Manuel Canales of The Washington Post. "The carnage is rarely visible to the public. Crime scene photos are considered too gruesome to publish and often kept confidential. . . . Medical examiners who, in some cases, have said remains were so unrecognizable that they could be identified only through DNA samples."

Joseph Sakran, a gunshot survivor and a trauma surgeon at Johns Hopkins Hospital, told the Post, "It literally can pulverize bones, it can shatter your liver and it can provide this blast effect." The Post explains, "The bullets from an AR-15 are uniquely lethal. . . . Consider a .223-caliber-sized round inside an AR-15. What makes the weapon so deadly is the speed of that bullet. It is small and light. Its cartridge holds enough propellant to send the bullet flying out of the barrel at a speed that would cross six football fields in a second."

Handgun rounds are heavier and slower. "Any bullet can kill, and instantly, when it hits a vital organ," the Post reports. "The higher speed of a bullet from an AR-15 causes far more damage after it hits the body and drastically reduces a person's chances of survival." Trauma surgeon Babak Sarani, an authority on casualties from mass killings, told the Post, "As that bullet slows down, that energy is so massive it has to go someplace, and your body will literally tear apart."

"In a hypothetical scenario, the bullet bursts into the chest cavity. It shreds lung tissue, severs nerves and vessels and causes massive bleeding. It also begins to tumble, taking a chaotic path in the body," the Post writes. "The speed at impact creates a blast effect, like the wake that follows a boat, causing internal injuries far outside the bullet's path."

And finally, "The bullet from the AR-15 leaves behind a gaping exit wound. The 9mm bullet fired from the handgun has a much smaller exit wound," the Post adds. "In this scenario, with immediate medical care and minimal bleeding, the victim has a chance at surviving the 9mm shot to the chest. . . . The bullet from the AR-15, however, causes torrential bleeding that is quickly lethal. . . . It works with brutal efficiency."

*Washington Post editor’s note: We are publishing these 3D animations to show the destructive power of the AR-15. The images may disturb some people.