Editor's note: We asked for questions about gun laws and received more than 1,700. Today we’re answering the top choice as determined by a reader vote. That question was submitted by a reader who preferred to remain anonymous. Look for the next Ask Star Tribune Opinion early next month.

How effective was the last assault weapons ban?

That was the top choice in online voting when the Star Tribune Editorial Board asked readers to submit their questions about gun laws. It comes in the wake of another senseless mass slaughter of innocents — this time students at a Florida high school gunned down by a former classmate — that has renewed interest in stricter gun safety measures, including, increasingly, a ban on the assault-style firearms that have become the weapon of choice in such incidents.

The original ban was enacted under the Violent Crime Control and Enforcement Act of 1994, which prohibited the manufacture for civilian use of a variety of military-style firearms, along with magazines holding more than 10 rounds of ammunition. The ban survived several court challenges, but Congress allowed it to expire in 2004.

Its effectiveness was limited from the start because it exempted all the banned weapons and magazines already legally possessed by their owners. Another bedeviling factor: There is no technical definition of “assault weapon,” so the feds resorted to banning specific makes and models, along with certain features. That led to the manufacture of modified weapons that could evade the ban. The 1999 mass shooting at Columbine High School, five years into the ban, involved the use of such a firearm, which was later reclassified as an assault-style weapon.

But as imperfect as the ban may have been, the number of mass shootings and the accompanying death toll fell during the 10 years it existed. Between 1984 and 1994, the U.S. saw 19 mass shootings (defined as six or more killed), with 155 deaths. During the decade of the ban, there were 12 mass shootings and 89 deaths.

In the 10 years after the ban ended, 34 mass shootings across the country claimed 302 lives. Most were marked by the use of assault-style weapons with large-capacity magazines. In 2012’s Sandy Hook Elementary School shooting, the gunman used a Bushmaster AR-15 semiautomatic rifle equipped with magazines that held 30 rounds each to slaughter 20 children and six adults.

In Las Vegas last year, a shooter killed 58 people and wounded hundreds more in minutes with an arsenal of assault-style weapons and high-capacity magazines.

Gun rights advocates say the original ban did little to lower overall gun violence and gun homicides. That’s true because most gun deaths in this country involve handguns. The federal ban was not intended to address overall gun violence, but rather as a means to address mass shootings.

Gun rights groups also note that other calculations — for example using a standard of four or more deaths per mass shooting — yield different statistics. That in itself is part of the difficulty in addressing effectiveness. Policy discussions continue to be hampered by federal restrictions on funding gun research, which the Editorial Board has repeatedly called for lifting. Until then, varying definitions and a hodgepodge of statistics will cloud any assessments — exactly the intent of those who would prefer none or few.

Some facts remain unassailable, though. A recent analysis by the New York Times found that most of the weapons used in the last 19 mass shootings were purchased legally and with a federal background check. An updated federal ban could have prevented many of those purchases. Would the shootings have occurred anyway? It’s possible. But without the firepower of a combat-style weapon, the death tolls might have been lower.

With a ban similar to the 1994 law in place, “You would see drastic reductions in what I call gun massacres,” Louis Klarevas of the University of Massachusetts at Boston told the Washington Post.

Klarevas, who analyzed a half-century of data on mass shootings for his book “Rampage Nation,” also said that when large-capacity magazines capable of holding 10 or more rounds are regulated as they were in the 1994 ban, “you get drastic drops in both the incidence of gun massacres and the fatality rate.”

In joining the growing calls for a renewed assault-style weapons ban last week, the Minnesota Medical Association, which represents about a third of the state’s doctors, also added its voice to the plea for more and better research. In an interview with a Star Tribune reporter, Dr. Jon Roesler, head of the state’s injury epidemiology program, put it succinctly: “You can’t prevent what you can’t count.”