One of Mike Laymon’s AR-15s pictured at Boulder Rifle and Pistol Club in Boulder City, Nev. on March 14, 2018. (Photo by Bridget Bennett for The Washington Post)
Cari S. Babitzke is a PhD candidate in history at Boston University.

“They say guns are just tools like knives and are as dangerous as cars,” said Parkland High School student Emma González. “We call BS. They say no laws could have prevented the hundreds of senseless tragedies that have occurred. We call BS. That us kids don’t know what we’re talking about, that we’re too young to understand how the government works. We call BS.”

Gonzalez’s speech at a rally in Fort Lauderdale re-energized a decades-long debate over the availability of firearms such as the popular AR-15 — commonly referred to by gun enthusiasts as “black rifles” — to the general public. Gonzalez and her fellow survivors rightly point out that one doesn’t need to be able to gunsplain to have an informed opinion about the political inertia that allows mass shootings such as Parkland to occur time and again.

But — and this is a very big but — technical details matter. Over the past three decades, gun manufacturers and enthusiasts have relied on technical details and the aftermarket adaptability of black rifles to skirt federal efforts at regulation and boost business. Today, any regulatory option with actual teeth would need to focus on the one trait all civilian-market black rifles share: their semiautomatic reloading capability. Should the federal government decide to ban all semiautomatic weapons, far more small arms than just the black rifle might be off the market.

Figuring out how to regulate these weapons requires first untangling a bit of history: How did the AR-15 become a civilian gun in the first place and how did it become so popular with gun owners?

The development of a new style of rifle crafted from modern industrial materials began as a side project at the ArmaLite Division of Fairchild Engine and Airplane Corporation. At the height of the Cold War, Eugene Stoner, ArmaLite’s chief engineer and creator of the AR-15, envisioned his weapon as an American answer to the Soviet-developed AK-47. In 1958, the Army tested the AR-15 as a possible replacement for its M-14 rifle, but did not commit to adopting the firearm at that time. By 1959, financial trouble convinced ArmaLite to sell its AR project to Colt Industries.

In 1962, the Army purchased its first run of 8,500 AR-15s for testing. Colt modified the weapon for fully automatic and semiautomatic selective fire and renamed it the M16. Though not always the most reliable weapon under combat conditions in the early years of the Vietnam War — maintenance- and ammunition-related issues cropped up during its introductory period — it became standard issue for service members in the conflict.

To address the battlefield problems, Colt made modifications to the M16. By 1967, American armed forces had a keen ally in the field: the M16A1 made of steel, aluminum alloy and composite plastic. It was a cutting-edge, lightweight weapon capable of firing up to 30 rounds at distances up to 800 meters (almost nine football fields), with small-caliber bullets moving nearly three times the speed of sound, capable of creating devastating wounds.

Following the success of its military contracts, Colt began marketing the AR-15 to civilians.  Available to the shooting public only in semiautomatic configuration as an alternative to wooden stock hunting rifles, the weapon initially met mixed reviews. But by the late 1980s, with law enforcement agencies buying the weapon in increasing quantities, its rising popularity on film and television and in nascent survivalist and militia movements, the AR-15 and its small- caliber, high-velocity cousins began making inroads with enthusiasts. Over the next three decades, it would become “America’s Rifle.”

On Jan. 17, 1989, Patrick Purdy walked onto his childhood schoolyard in Stockton, Calif., and opened fire with a semiautomatic AK-47. In a scant few minutes, Purdy killed five children and left 32 others wounded before committing suicide. In the wake of the shooting, Colt suspended sales of its AR-15 out of concern that its domestic production might be included in the 1989 ban on semiautomatic rifle imports such as the Uzi and AK-47. But by 1990, the manufacturer reversed course, slightly modifying the weapon for the civilian market in an effort to keep ahead of a possible full ban on all “assault rifles.”

Purdy’s was but one of the earliest shootings in an ever-growing list: Luby’s Cafeteria in October 1991, 101 California Street in July 1993. Such violence intensified efforts at the federal level to address public concern about mass shootings committed by men with too-easy access to semiautomatic weapons and large-capacity magazines, ultimately resulting in the inclusion of the federal assault weapons ban in the Violent Crime and Law Enforcement Act of 1994.

But even with this legislation, thousands of black rifles and large-capacity ammunition magazines still made their way onto the market in the early 1990s as manufacturers doubled and tripled production before the provisions took hold. Because the ban included exemptions, exclusions and loopholes, it was still relatively easy for an individual to purchase a weapon or magazine purportedly banned by law. And after the law went into effect, manufacturers made cosmetic changes to the weapons whose sale was meant to be regulated by the law.

In short, the ban was largely toothless. Even so, since it expired on Sept. 13, 2004, efforts to renew or replace it have been unsuccessful — as the list of shootings continues to grow.

Even with a decade of regulation under the ban, sales of black rifles exploded over the past 30 years for myriad reasons. Threats of a ban only intensified demand. The rising popularity of first-person-shooter video games and Hollywood’s affinity for black rifles have increased their familiarity and visibility to the American public. Manufacturers of rifles and accessories also rely on “tacti-cool,” selling black rifles using military and law enforcement imagery to veterans of the forces and non-service members of the public. Finally, a subset of civilians increasingly concerned about the potential for governmental tyranny, regulation of black rifles and accessories or “SHTF events” — doomsday disasters — have been especially reliable consumers for firearms manufacturers from the turn of the 21st century to the present.

Today, black rifles come in multiple calibers and can be personalized into nearly infinite varieties: Very few owners shoot these weapons as sold “off the shelf.” Gun enthusiasts even have the option to purchase an 80 percent complete AR-15-style lower receiver — without a serial number — (or even 3D-print a lower) and use an aftermarket jig to mill the parts to build a black rifle at home. And because the Bureau of Alcohol, Tobacco, Firearms and Explosives does not classify the incomplete lower as a gun, federal firearms licensed (FFL) dealers aren’t required to run background checks on the purchaser of these parts. In fact, the buyer can choose to skip the storefront FFL dealer and purchase a new lower from an unlicensed seller at a gun show or on the Web.

In short, those with Internet access, a modicum of mechanical skill and a few tools have the potential to effectively bypass the entire regulatory system for firearms purchases.

Customizable and accessorizable to the nth degree, black rifles have become like Barbies for gun owners: Each owner can modify the rifle to suit his shooting style and tastes. These technical variations complicate efforts to regulate the weapons. The public may “know one when they see one.” But firearms manufacturers, organizations and black-rifle enthusiasts have and continue to rely on the minutiae of technicalities to effectively stymie efforts toward regulation.

And if the goal for gun-control advocates is a blanket ban on all black rifles, the regulation would need to be so broad to address the technical variety in this class of guns that it might sweep up all semiautomatic firearms — rifles and handguns, imported and domestic — into its provisions. Should the young people of the United States maintain the regulatory momentum they seek, responsible firearms owners who wish to keep their access to semiautomatic weapons would be well served to find a spirit of compromise on universal background checks or age restrictions instead.