Americans Are Slow Learners

Other countries banned many firearms when the human toll of allowing them to be legally available became clear. But, Americans are apparently slow learners.

United States

Most firearm-related homicides in the United States involve handguns. A 2019 Pew Research study found that 4% of US gun deaths were caused by semi-automatic rifles, a category which includes AR-15 style rifles. According to a 2013 analysis by Mayors Against Illegal Guns, 14 out of 93 mass shootings involved high-capacity magazines or assault weapons. Nevertheless, AR-15 style rifles have played a prominent role in many high-profile mass shootings in the United States and have come to be widely characterized as the weapon of choice for perpetrators of these crimes. AR-15s or similar rifles were the primary weapons used in half of the 10 deadliest mass shootings in modern American history: the 2012 Sandy Hook Elementary School shooting, the 2017 Las Vegas shooting, the 2017 Sutherland Springs church shooting, the 2018 Stoneman Douglas High School shooting, and the 2022 Robb Elementary School shooting. 

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Australia

Following the use of a Colt AR-15 rifle in the Port Arthur massacre, the worst single-person shooting incident in Australian history, the country enacted the National Firearms Agreement in 1996, restricting the private ownership of semi-automatic rifles. (Category D). 

New Zealand

As a result of the Christchurch mosque shootings with an AR-15 during Friday Prayer on March 15, 2019, the New Zealand government enacted a law to ban semi-automatic firearms, magazines, and parts that can be used to assemble prohibited firearms.

Canada

After the 2020 Nova Scotia attacks, the deadliest rampage by a single person in Canadian history, Canada banned a class of firearms, including the AR-15.

From here.