So should we give up on banning dangerous firearms? Absolutely not. The reason these laws have proved ineffective isn’t because a ban can’t work; it’s because none have addressed the underlying characteristic that makes some firearms so lethal in the first place: their ballistics.

After O’Sullivan’s death, Sacramento’s grieving police chief pointed out that “bulletproof” vests are no match for high-power rifles. He’s correct. According to FBI data, 471 police officers were feloniously shot and killed in the United States during the past decade. More than 100 were killed by rifles, 65 in the powerful .223, 5.56 mm and 7.62 mm calibers common to assault-style weapons. Rifles also figured in 20 of the 21 fatalities caused by rounds that penetrated body armor.

California, six other states and the District “ban” assault weapons. But these laws skirt around caliber. Instead, they focus on a weapon’s physical attributes. For example, California requires that semiautomatic firearms with external baubles such as handgrips have non-detachable magazines and limits ammunition capacity to 10 rounds.

Those characteristics, though, aren’t the main reason assault-style weapons are so dangerous. That’s fundamentally a matter of ballistics. High-energy, high-velocity .223-, 5.56- and 7.62-caliber projectiles have unbelievable penetration power. When these bullets pierce flesh, they produce massive wound cavities, pulverizing blood vessels and destroying nearby organs. Rifles can deliver this mayhem from a distance. That’s what happened in 2017 when an ostensibly law-abiding gambler opened fire with AR-15-type rifles from his Las Vegas hotel room, killing 58 and wounding more than 400 others.

Such massacres have become commonplace. On Aug. 3, a 21-year-old man allegedly used an AK-47-style rifle to kill 22 and wound more than two dozen at an El Paso shopping center. One day later, a 24-year-old man donned body armor, grabbed an AR-15-type rifle and burst into a Dayton, Ohio, nightclub, killing nine and wounding more than two dozen. Then came the carnage in West Texas, where another AR-15-style rifle was used to kill seven and wound 22, including three police officers.

Despite the deplorable toll, not one state has dared address ballistics. Why? Because it might offend hobbyists who get a thrill from tinkering with powerful guns, as well as citizens who want such weapons for self-defense. It would also threaten the interests of the gun industry, whose economic viability depends on producing and importing ever-more-formidable hardware.

So lawmakers have chipped away at the margins — say, by limiting ammunition capacity. But even 10 highly lethal rounds are an awful lot. With guns and gun parts readily available from private parties and through the Internet, restrictions on how weapons are configured are also easy to circumvent. Consider the 2015 San Bernardino massacre, when a married couple murdered 14 and wounded 22 with a pair of state-legal AR-15 clones. Both weapons had been modified to accept high-capacity magazines, in a simple process that’s described online.

Bottom line: Many semiautomatic firearms are exceptionally lethal whether they’re short- or long-barreled, have handgrips or extended magazines. What can be done? Following the examples set by Britain and, most recently, New Zealand, we could ban them outright. Or we could create a scale of lethality, assigning scores for penetration ability and wounding effect along with ammunition capacity, rate of fire and accuracy at range. Guns that wind up at the dangerous extreme could be prohibited, while others would be subject to a range of controls.

Of course, even the best-crafted scale won’t solve our epidemic of gun violence. By all means, expand background checks and implement “red flag” laws. But don’t use that as an excuse to keep ignoring what lies at the root of the mayhem: fearsome ballistics. Address that, and the toll will ease.