Clif Cleaveland: AR-15 is a vector for terror

Clif Cleaveland: AR-15 is a vector for terror

February 27th, 2018 by Dr. Clif Cleaveland in Life Entertainment


The price cited in last week’s column for the recommended two injections of Shingrix vaccine was erroneous. In Chattanooga pharmacies, the retail cost ranges from $300 to $350 for two doses.

Dr. Clif Cleaveland

Dr. Clif Cleaveland

Photo by Contributed Photo /Times Free Press.

In epidemiology, a vector is an organism that transmits a disease-causing parasite, virus or bacterium from one animal to another. In malaria, a species of mosquito bites a person who is infected with the parasite. The parasites multiply within the mosquito before being transmitted to the next person bitten.

In plague, a flea transmits the bacterial agent from an infected rat or prairie dog to a person.

The black-legged tick carries the bacterium of Lyme disease from deer to humans.

Let us stretch the definition of vector and consider a specific firearm as a vector for massacres of civilians, transmitting hatred from the shooter to cause death and injury among victims.

The vector in this instance is the AR-15. This semi-automatic weapon was used in mass murders in Newton, Connecticut; Aurora, Colorado; San Bernadino, California; and most recently at Marjory Stoneman Douglas High School in Parkland, Florida.

ArmaLite Rifle, a small engineering company, developed the AR-15 in the late 1950s. Colt's Manufacturing Co. bought the company in 1959. Patents on the AR-15 expired in 1977. Many companies currently manufacture the weapon with a variety of modifications.

An AR-15 retails for $800 to $1,800.

The AR-15 is semi-automatic, meaning one trigger pull fires one round. Illegal modifications can make the weapon automatic. Modification with a bump stock, which was legalized by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) in 2010, allows firing up to nine rounds per second. A typical bullet has a diameter of .223 inches (5.66 millimeters), weight of 3.6 grams and a soft, lead center encased in a harder metal alloy.

The AR-15 has a muzzle velocity up to 3,200 feet per second with an effective range of 500 yards.

Magazines of varying capacity are attached to the AR-15. As of 2014, eight states and the District of Columbia limit the capacity of attached magazines to 20 or fewer rounds. California limits capacity to 10 rounds; New York has a seven-round limit. Magazines with capacities up to 50 rounds can be purchased.

On Dec. 21 last year, the coroner released the autopsy reports of the 58 people murdered in the mass shooting in Las Vegas on Oct. 1. Two of the killer's AR-15s had been modified with bump stocks. Autopsies documented the extensive damage that a single bullet could cause to multiple organs A bullet might fragment on impact, sending high-velocity fragments in multiple directions. Some of the Las Vegas victims sustained injuries to chest and abdominal organs from a single bullet. Alternately, a bullet might tumble upon entry, widening its path of destruction. Heat from rapid firing leads to barrel expansion, which causes bullets to tumble as they exit the barrel, thereby inflicting more damage on human targets.

In 1994, Congress passed the Federal Assault Weapons Ban by a 52-48 vote. President Clinton signed the act into law, which banned specific models and features of semi-automatic rifles and pistols. The act expired in 2004.

Seven states — California, Connecticut, Hawaii, Maryland, Massachusetts, New Jersey and New York — have enacted restrictions on the sale and ownership of AR-15 and similar weapons.

Detailed background checks should identify persons who should not own firearms. If Congress and state legislatures care about reducing deadly firearm vectors, these assemblies will need to consider: 1) age limits on purchase of AR-15 and similar weapons; 2) uniform limits on magazine capacities; 3) bans on bump stocks and other accessories that increase rapidity of fire. Should a national ban on these weapons and accessories be enacted, similar to the 1994-2004 law? This is one of the most vital and contentious issues facing our nation.

The voices of victims, their families, friends and classmates along with law enforcement officers and first-responders must be respectfully heard and factored into the debates on gun-related legislation. Unlike lobbyists, they have witnessed the carnage of mass shootings firsthand.

"The Gun" by C.J. Chivers provides an excellent history of the development and consequences of automatic and semi-automatic weapons.

Clif Cleaveland, M.D., is a retired internist and former president of the American College of Physicians. Email him at

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