When Lawmakers Try to Ban Assault Weapons, Gunmakers Adapt As the United States witnesses dozens of mass shootings each year, one proposal to limit the carnage turns up again and again: an assault weapons ban.

Even though military-style weapons are used in few shootings, they have proven to be the deadliest, and the most visible targets for legislation.

But the nature of today’s most popular rifles — and the determination of gunmakers, firearms hobbyists and Second Amendment enthusiasts — means weapons bans have worked better in theory than in practice.

Gunmakers and owners can modify guns in ways that keep the weapons legal but nearly indistinguishable from illegal assault weapons.

Modern sporting rifles, patterned after the Colt AR-15, are versatile platforms for accessories. Their tactical attachments help make them popular.

California was the first state to define and ban assault weapons, after an elementary school shooting in 1989. As in seven other states, it is illegal to sell or import high-capacity magazines for rifles that can hold more than 10 rounds.

California has also tried regulating guns with lower-capacity detachable magazines that make reloading faster — and potentially deadlier in a mass shooting scenario.

It is illegal for a rifle with a detachable magazine to have certain other features that lawmakers say belong on the battlefield .

Gun owners say those features are largely cosmetic and don’t necessarily make the weapon more dangerous. The proof, they say, is that the same features remain legal for rifles with a fixed , or attached, magazine.

Gun owners who wanted these features still valued the quick-change performance of a rifle with a detachable magazine. So gunmakers engineered a solution.

They added a magazine release that required a tool as simple as a bullet and made reloading easier.

In 2016, after the San Bernardino shooting, California lawmakers tried again. They banned bullet buttons and introduced a new definition for fixed magazines .

To replace the magazine, the gun must be “ disassembled ” and the firearm action opened. In theory, this requirement would slow reloading times.

It did not take long for gunmakers and third-party manufacturers to find a way to comply with the law while still offering consumers a similar product with all the same accessories.

Inexpensive modification kits on the market now make it quick and simple to “disassemble” the rifle.

These allow the firearm action to open slightly with the press of a button. The magazine can then be removed with a traditional release. The banned features become legal again.

As a result, the latest AR-15 patterned rifles are not that different from the assault weapons California banned in 1989.

Federal restrictions have seen a similar response from gunmakers.

After the 2018 Las Vegas shooting — the deadliest mass shooting in modern U.S. history — the Justice Department banned bump stocks , which the shooter used to fire more than 1,100 rounds in 11 minutes.

But a recent trigger adaptation, called a binary trigger , increases firing speed much like a bump stock and is legal in many states. It allows the firearm to shoot one bullet when the trigger is pulled …

… and one when it is released .

A 30-round magazine can be emptied in about three seconds .

A federal judge recently upheld California’s assault weapons ban, ruling that semiautomatic assault rifles were “ essentially indistinguishable ” from machine guns. Similar bills were introduced in the United States House and Senate this year.

Yet the modifications remain legal, and gunmakers will most likely respond to future restrictions with fresh adaptations.