Although AR-15-style rifles have been sold commercially since the 1960s, for a long time there was barely a market for them. In 1990, they accounted for just 1.2 percent of all firearms manufactured in the United States. But starting in the mid-2000s, after the assault weapons ban expired, their appeal grew. The wars in Afghanistan and Iraq gave AR-15-style rifles a certain cachet — people wanted the same guns the soldiers were using. The spike in sales was also influenced by politics, including the election of the country’s first Black president. Concerns about new gun-control measures, coupled with fears about where the country was heading, caused a surge in demand. According to a recent poll commissioned by The Washington Post, about one in 20 Americans now own an AR-15-style rifle. The Post cited a gun-industry estimate that there are currently around 20 million AR-15-style rifles in private hands, although that number was not confirmed independently. They have become so popular that they are often referred to these days as “America’s rifle.” Representative Barry Moore, an Alabama Republican, recently introduced legislation to designate the AR-15 “the national gun of the United States.” Some Congressional Republicans have taken to wearing AR-15 lapel pins.

AR-15-style rifles have been involved in some of the worst mass shootings that the United States has experienced over the last decade or so, including those in Las Vegas; Orlando; Sutherland Springs, Texas; Parkland, Fla.; and San Bernardino, Calif. In the view of Koskoff and others, the firearms industry bears considerable blame for this — not only because it continues to sell AR-15-style rifles but also because gun advertising has become increasingly provocative. Many ads for AR-15-style rifles play up their lethality, even glamorize it. A lot of the marketing seems directed at one group in particular: young men. Masculinity is a common theme, as are appeals to male grievance. In 2012, a few months before Sandy Hook, Bushmaster published an ad in the men’s magazine Maxim that featured a picture of an AR-15-style rifle with the caption, “Consider your man card reissued.” Gun makers have also cultivated buyers through popular first-person shooter games like the Call of Duty franchise that showcase their AR-15-style weapons (the virtual versions look identical to their real counterparts and sometimes sport the brand names). Adam Lanza reportedly played Call of Duty games obsessively. Gun companies, Timothy Lytton says, are “marketing semiautomatic rifles to young people in the form of fantasy games that deliver the experience of shooting to kill as a form of entertainment.”

Daniel Defense, a Georgia firearms manufacturer, has generated particular controversy with its marketing. One ad, which was posted on the company’s Twitter account a few months before Robert Crimo III began shooting people from a Highland Park rooftop, displayed a rifle mounted on top of a building, with the lights of a city or town visible below; an adjoining photo showed the view through the gun’s sight — it was of a parked vehicle. The caption read, “Rooftop ready, even at midnight! 🌚” The gun maker has also been accused of deploying racist imagery: A few years ago, its catalog included a picture of a man with a Valknot tattoo; the Valknot is a Norse symbol embraced by white supremacists.

A recent congressional report said that Daniel Defense’s annual revenues from sales of AR-15-style rifles tripled between 2019 and 2021, to over $120 million from $40 million. A Daniel Defense DDM4 V7, an AR-15-style semiautomatic weapon, was used in the shooting last May at Robb Elementary School in Uvalde, which left 19 fourth graders and two teachers dead. According to a report commissioned by the Texas House of Representatives, the teenage gunman, Salvador Ramos, a former student at Robb Elementary, purchased the rifle for around $2,000 shortly after his 18th birthday. (Daniel Defense did not respond to a request for comment. In congressional testimony last year, Marty Daniel, the company’s founder and at the time its chief executive, denied any responsibility for Uvalde, saying, “These murders are local problems that have to be solved locally.”)

The Texas House report also included personal details about Ramos, who was killed by law-enforcement officers after they entered the school. A native of Uvalde, he came from a broken home, spoke with a stutter and had been bullied by classmates. When he was 17, he was expelled from high school, having only completed ninth grade. In the year that followed, he went into a spiral. He dressed in black clothes and combat boots and retreated to the online world — he was active on several social media platforms and also played violent video games, including the Call of Duty series (in which the Daniel Defense DDM4 V7 has appeared). “Most of his usernames and even his email address reflected themes of confrontation and revenge,” the report said. It added that he became fascinated with the idea of acquiring notoriety and developed an interest in school shootings. Some of his online peers jokingly nicknamed him “school shooter.”