Besides his penchant for domestic abuse and his military background, another interesting connection emerged between the Sutherland Springs shooter and other recent killers. His weapon of choice was the AR-15, which seems to have become a favorite of mass murderers as of late. As Michael Skolnik pointed out on Twitter this week, the men behind mass shootings in Aurora, Orlando, Las Vegas, Sandy Hook, Umpqua Community College, San Bernardino, and now Sutherland Springs all used the rifle, a semiautomatic gun licensed to Colt but with variations produced by several other manufacturers.

USA Today notes that the weapon has exploded in popularity in recent years, more than doubling in the past 10 years to about 3.7 million rifles manufactured in 2015. But the AR-15 is still not as renowned as other semiautomatic rifles, and its popularity is dwarfed in comparison to the handgun. So why has this particular gun become so popular for mass shooters? It may be because the gun is particularly fetishized by men under 30, the demographic for many of these killers. The gun industry and pro-gun media market the semiautomatic rifles to the most juvenile of gun enthusiasts, fostering a dangerous obsession with deadly weapons among immature young men.

It's likely that the shooters all chose the AR-15 because they were modeling their behavior on other highly publicized killers before them. Master firearms instructor Dean Hazen, owner of the Gun Experts in Mahomet, Ill., told USA Today he thinks mass shooters prefer the AR-15 based on nothing besides a "copy-cat" mentality. "It’s really just a perception thing," Hazen said. "There are rifles that are more powerful and more dangerous than that, but they're not being used." Shooters also like that the semiautomatic rifle is a civilian version of the similar M-16, used by the American military.

While it’s certainly possible that mass shooters choose their weapon on a copy-cat instinct, there are important technical reasons why the AR-15 is so preferred. The AK-47 is more well-known in American culture, but while the two guns are similar, TacticalGear.com explains, the AR-15 is more user-friendly, as it shoots farther, fires more rounds per minute and is lighter than the AK-47. Thus, in many ways, it’s more fearsome.

These weapons are also easier for shooters to get their hands on, not due to any specific loopholes (it’s already incredibly easy to purchase a gun in some states), but because of the AR-15’s pricetag—it’s generally cheaper than other semi-automatic weapons. One version has a retail price under $800, according to Voice of America while some are available for as little as $500. As Guns and Ammo wrote in its review of the particular model of AR-15 used by the Sutherland Springs shooter, “the best part of all” when it comes to the rifle is that it is “manufactured in the USA, and you won’t have to refinance your house to own one.”

Gun enthusiasts agree that the wide variety of customization options makes the AR-15 even more appealing. In a write-up on the gun titled “Why the AR-15 is America’s most popular rifle,” the NRA blog explains that “AR-15s can be skinned or wrapped in all different types of colors and patterns,” such as this one, which appeals particularly to those who stockpile weapons in preparation for the zombie apocalypse:

The blog post encourages fans of the AR-15 to “Make it even cooler and #FightTheNoise – add a suppressor from SilencerCo.”

SilencerCo is one of Donald Trump Jr.’s favorite gun accessory companies. In a promotional video for the company, he cheerily advocates for gun silencers, claiming his own hearing has been damaged as a result of firing too many non-sound-suppressed guns, and insists on the importance of “getting little kids into the game” to protect them from a similar fate. Trump Jr. is one of the more prominent manchild gun lovers, but there are plenty of others like him, and they form a major subculture within gun enthusiasts that seems particularly linked to the AR-15.

The Week’s Matthew Walther sees a connection between the killers at Sandy Hook, Aurora, Orlando, and this week in Texas: all were men under 30 with a childlike obsession with semiautomatic rifles, part of the community of "revoltingly adolescent, video-game-addicted LARPers who think that their hobby of playing dress-up with murder weapons is a constitutional right.” Writing about what he terms the “adolescent cult” of the AR-15, Walther explains how AR-15 enthusiasts often fetishize their weapons, like one who reviewed the "'gotta have it' accessories that’ll turn your AR into something fierce.” The same review glowingly endorsed products such as a muzzle device that “looks stupidly sexy on even a bone stock gun” and will help you in “close quarters fighting or even shooting out of a vehicle.”

Much has been written about Hollywood’s glorification of guns over the years and the impact it has had on young mass shooters. The Columbine killers were teenagers notoriously obsessed with the Matrix who dressed in black trench coats like the movie's characters when they entered their high school to kill 13 people. Certainly, television and film glamorize weapons, especially in productions targeted at young men who think guns will make them appear more manly. But the gun industry has followed Hollywood's lead. For years, gun companies have been using the association between guns, toughness and masculinity in order to sell the AR-15. Bushmaster ran an ad campaign featuring a semiautomatic rifle positioned next to the tagline, “Consider your man card reissued.”

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(Photo Credit: Ammoland)

In 2016, a girls’ softball team in Oregon raffled off an AR-15 as a fundraiser. Then, just a week after the Las Vegas shooting, a Mississippi church used two of the rifles to raise money, and had children manning the raffle ticket table. An Oregon high school auctioned off the AR-15 to raise money for the booster club. Many of the parents who defend this behavior insist that fostering a love for guns in their children is part of the great American tradition of preserving the Second Amendment.

If gun culture isn’t busy marketing guns to children (and man-children) who salivate over them, it’s flipping the Oedipal narrative on its head, encouraging people to care for their AR-15s much as they would their own family members. In a piece on “Great Ways to Trick Out Your AR-15,” Guns and Ammo pays homage to the “Rifleman’s Creed,” which “emphasizes the importance of building a bond with your rifle, learning how it works and respecting it as a best friend or brother.”

The piece continues, “tricking out an AR-15 is the perfect way to personalize a rifle and simultaneously build a bond with it.” When describing a rifle purchase, the author draws a creepy analogy to welcoming a new baby into the home, writing, “Most folks who buy a new AR-15 usually have plans for how to accessorize it before they even bring it home.” The article is filled with rhetoric that personifies the AR-15, encouraging readers to “transform it into something you can proudly call 'my rifle.'”

Considering the lonely, alienated nature of mass shooters, it’s no wonder they’re drawn to weapons the gun industry promises will become their new “best friend.”