It comes in black, tan and camouflage. A pink version was once raffled by a gun store to raise money for breast-cancer research.
Favored by target shooters in competitions and by hunters who stalk small game and sometimes deer, its customizable features — stocks, grips, sights, barrel lengths — are endlessly discussed by enthusiasts in online forums. It ranks high among the firearms purchased for self-defense.
But the AR-15 style rifle — the most popular rifle in America, according to gun dealers — was also the weapon of choice for Adam Lanza, police said, who used one made by Bushmaster on Friday to kill 20 young children and six adults in an elementary school in Newtown, Conn., in a massacre that has horrified the nation.
The increasing appearance of the rifle in rampage killings — police officials say an AR-15 was used by James E. Holmes, who is accused of opening fire and killing 12 people in a movie theater in Colorado in July, and by Jacob Roberts, who killed two people then took his own life in a shopping mall last week near Portland — has rekindled the debate about its availability and its appeal to killers bent on mass slaughter.
Most Read Stories
It has also starkly highlighted the chasm between those who favor tighter regulation for firearms and those who believe that guns like the AR-15 are widely misunderstood and wrongly blamed for the actions of a few individuals.
Gun-control advocates contend that semiautomatic weapons like the AR-15 — the civilian version of the military’s M-16 and M-4 — are a logical choice for anyone whose goal is to kill a lot of people in a short time, because of their ability to rapidly fire multiple high-velocity rounds.
“The people we’re talking about, once they get into ‘I want to kill a lot of people,’ it’s not a leap for them to see that these guns are made and designed for war,” said Tom Diaz, a senior policy analyst at the Violence Policy Center. “And if you look at the industry advertising, that is a consistent theme.”
AR-15s are not the only weapons used by rampaging shooters. Semiautomatic handguns are also frequently employed.
In Newtown, in addition to the Bushmaster M-4 carbine, two handguns were found at the scene, a 10-mm Glock and a 9-mm Sig Sauer, although the rifle is what Lanza used, spraying up to 11 bullets into each victim’s body, according to the medical examiner. All three guns belonged to his mother, officials said.
In Colorado, Holmes carried two Glocks and a shotgun, officials said, as well as the AR-15. A Glock and a Walther were used by Seung-hui Cho to kill 32 people and injure 17 at Virginia Tech in 2007.
Diaz said that semiautomatic weapons, including the AR-15, increasingly are being used in the killings of police officers, whose vests often provide little protection against such firearms.
In the wake of the Newtown shooting, he and others have called for a ban on the high-capacity magazines routinely used with such firearms, which feed 20 or 30 rounds at a fast pace. (In Colorado, officials said Holmes used a 100-round drum magazine that gun dealers say is primarily a novelty item that is likely to jam, as Holmes’ rifle apparently did.)
Some advocates have argued for banning assault rifles, though some of them also acknowledge that the federal assault-weapons ban, which expired in 2004, was inadequate and largely ineffective.
Defenders of the firearm, however, say it is misguided to blame a gun that is used by millions of owners across the country in a responsible manner.
They argue that unlike its military counterparts, the civilian models of the AR-15 are almost all semiautomatic, not fully automatic, and so should not be classified as assault rifles.
Critics describe them as high-power weapons — in addition to firing multiple rounds quickly, their muzzle velocity is almost double that of a typical traditional shotgun. But defenders say that most AR-15s are chambered for .223 or 5.56-mm ammunition, low-caliber rounds that are less deadly than those used in many handguns.
And they cite statistics indicating that unlike handguns or shotguns, rifles account for only a fraction of U.S. homicides — out of 12,664 murder victims last year, 323 were killed with rifles, according to the FBI’s Uniform Crime Report.
What neither side questions is the popularity of AR-15s, which dealers say fairly leap off the shelves.
Gun makers do not release sales figures for specific types of firearms. But Stephen Halbrook, a constitutional lawyer in Virginia who compiled manufacturing estimates for a lawsuit, said that by a conservative estimate, between 3.3 million and 3.5 million AR-15s were made in the U.S. from 1986 through the first half of 2012 and were not exported. A similar estimate, for manufacturing from 1986 through 2009, was summarized by a District of Columbia circuit-court judge as sufficient evidence that the rifles were in “common use.”
“They get a lot of coverage when there’s a tragedy with one but the number of people unlawfully killed with them is small,” said Halbrook, who has argued high-profile Second Amendment cases and has represented the National Rifle Association.
Enthusiasts praise the AR-15 rifle as lightweight, durable, accurate and, compared to other long guns, gentle in its kick. They describe the rifle as a gadget geek’s dream — the “Barbie doll” of firearms, as one gun dealer described it — because of an array of accessories that allow it to be easily customized.
“The average person can change stocks, they can put lasers on them, they can put locks on them,” said Tony Dee, chief gunsmith at The Gun Store in Las Vegas.
“It’s just endless. It’s like building a custom car. You can just accessorize it to your own personal taste.”
Although in some states, AR-15s with certain cosmetic features are banned from sale — in Connecticut, the guns cannot be sold with collapsible stocks or removable muzzle brakes — manufacturers continue to sell models in those states without such features. Buyers who want those features can easily add them by themselves.
In a 2011 survey conducted by the shooting-sports foundation, gun dealers reported that 49.1 percent of the AR-15-style rifles they sold were bought for target shooting, up from 46.3 percent in 2009. Hunting accounted for 22.8 percent of sales and personal protection 28.1 percent.
Yet even some gun sellers acknowledge that some of their customers choose AR-15s for reasons that have little to do with plinking at cans or hunting prairie dogs.
The optional grenade launchers offered on some models have a particular appeal, one gun salesman said.
He added that although he did not want to make his customers sound crazy, the different types of ammunition available for AR-15s made them attractive to people “who want to be prepared for an Armageddon-type situation.”