(CNN) When a killer gunned down 50 people this month at two mosques in Christchurch, New Zealand, it took lawmakers there 72 hours to ban assault rifles and high-capacity magazines .

After 26 people were killed at a US elementary school in 2012, there were widespread calls for universal background checks. More than six years later, they still haven't materialized.

Both countries have a culture of gun ownership and a strong gun lobby . But there are clear differences.

The right to own a gun isn't enshrined in New Zealand's constitution. And the aftermath of the Christchurch massacre shows there's a greater sense of urgency to enact national gun-control legislation in New Zealand after a mass shooting than in the United States.

Here's a look at some of the new laws enacted after US mass shootings, and how long each took.

Las Vegas

What happened: On October 1, 2017, a gunman opened fire from a hotel window on a crowd of outdoor concertgoers, killing 58 people in the On October 1, 2017, a gunman opened fire from a hotel window on a crowd of outdoor concertgoers, killing 58 people in the deadliest mass shooting in modern US history

Bullets pummeled the crowd of 22,000 with devastating speed due to bump stocks -- accessories that make semiautomatic guns fire quicker.

What's changed since: In November 2017, Massachusetts became In November 2017, Massachusetts became the first state to ban bump stocks after the Las Vegas mass shooting.

The Trump administration banned bump stocks nationwide on December 18, 2018. Owners were given 90 days to turn in or destroy their bump stocks.

How long it took: Massachusetts banned bump stocks one month after the Las Vegas massacre. It took 14 months for the federal government to do so.

Parkland, Florida

What happened: On February 14, 2018, a teen used an AR-15 rifle to kill 17 people at Marjory Stoneman Douglas High School.

What's changed since: Florida Gov. Rick Scott signed the Florida Gov. Rick Scott signed the Marjory Stoneman Douglas High School Public Safety Act

The new law raised the state's minimum age to purchase a firearm to 21; required a three-day waiting period for firearm purchases; banned the sale or possession of bump stocks; and allowed law enforcement officers to ask the court to temporarily prohibit someone from possessing or buying firearms.

One of the more controversial parts of the new law is known as the Coach Aaron Feis Guardian Program, which allows some teachers to be armed if both the local school district and local sheriff's department agree.

How long it took: Scott approved the new legislation three weeks after the Parkland massacre.

Newtown, Connecticut

Connecticut added more than 100 guns to its list of banned assault weapons , banned armor-piercing bullets, and limited gun magazines to a capacity of 10 rounds.

Kansas, by contrast, said federal gun laws would no longer be enforced and that any federal agent who tried to enforce federal laws would face arrest, jail time and a fine. The state also started recognizing concealed-carry permits from other states.

And while the Sandy Hook gunman had no criminal background and got access to guns through his mother, the shooting renewed calls for Congress to require universal background checks for gun sales.

How long it took: It took four months for Connecticut to pass sweeping gun control reforms.

Obama ordered the CDC research and called for universal background checks a month after Sandy Hook. But six years later, there is no federal law requiring universal background checks.

Sutherland Springs, Texas

What happened: On November 5, 2017, a gunman On November 5, 2017, a gunman killed 25 people and an unborn child at a Baptist church in Sutherland Springs.

Officials said the gunman shouldn't have been able to buy a gun . He had been previously convicted in a military court of assaulting his spouse and their child.

But the US Air Force said the conviction was not properly entered into the federal law enforcement database. So when the attacker went to a store to buy the gun, he was able to do so.

What's changed since: US Sen. John Cornyn pushed for the US Sen. John Cornyn pushed for the Fix NICS (National Instant Criminal Background Check System) bill. The bill didn't strengthen background checks , but instead incentivized state and federal authorities to report more data to the database