In the last 10 days, two tragic mass shootings were carried out by 18-year-olds wielding semiautomatic rifles: 10 people were killed and three others injured in the May 14 attack at a supermarket in Buffalo, New York, and 21 people are dead, 19 of them children, after the May 24 shooting at Robb Elementary School in Uvalde, Texas.
Both teenage gunmen acquired their rifles legally, through federally licensed dealers. Federal law allows people as young as 18 to buy long guns, including rifles and shotguns, and only a handful of states have enacted laws raising the minimum age to 21. There’s no federal minimum age for the possession of long guns, meaning it’s legal to give one to a minor in more than half the country.
The Buffalo shooting suspect wrote in his online screed that his father gave him a hunting rifle for Christmas when he was 17, and that he bought the rifle used in his racist rampage — a Bushmaster XM-15 — from an upstate New York gun dealer shortly after he turned 18. Both transfers were in compliance with state law. The Uvalde shooter reportedly bought two semiautomatic rifles soon after he turned 18, on May 16.
Research has shown that adolescents are responsible for a disproportionate share of the nation’s gun violence.
Nonetheless, New York and Texas are among 44 states that allow 18-year-olds to buy long guns, including semiautomatic rifles, according to Giffords Law Center, which tracks state and federal gun laws. Only six states have raised their long gun purchasing age to 21: California, Florida, Hawaii, Illinois, Vermont, and Washington State. Americans are meanwhile not allowed to purchase alcohol or cigarettes until they are 21.
Possession laws are even more permissive. Twenty-nine states allow minors to possess long guns, including New York, Texas, Virginia, and Connecticut. Nineteen states set the minimum age at 18, including California, Florida, Michigan, and New Jersey. Only three states and Washington, D.C., set the minimum age at 21: Hawaii, Illinois, and Maryland (though D.C. exempts 18-year-olds with parental consent, and Maryland’s age minimum pertains to assault weapons only).
Experts have argued that adolescents lack the maturity to responsibly use firearms. Cassandra Crifasi, a gun violence researcher at Johns Hopkins and a longtime gun owner, wrote in a 2019 commentary piece for The Trace:
While an 18-year-old’s brain is similar to that of a fully mature adult, key cognitive processes continue to develop until age 26. These include impulse control, which can affect an individual’s ability to safely and appropriately use a gun.
According to a 2020 analysis of FBI homicide data by Everytown for Gun Safety, 18-to-20-year-olds are responsible for 18 percent of gun homicides despite accounting for only 4 percent of the population. (Through its nonpolitical arm, Everytown provides grants to The Trace. You can find our donor transparency policy here, and our editorial independence policy here.)
Higher age limits on gun sales are not well studied, especially when it comes to the effect they might have on preventing mass shootings. The RAND Corporation found some evidence that raising the minimum age for all gun sales to 21 could reduce youth gun suicide.
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Age requirements for long guns first gained national attention in 2018, after a 19-year-old was able to legally buy an AR-15 and kill 17 people at Marjory Stoneman Douglas High School in Parkland, Florida. Three weeks later, Florida’s GOP governor signed a law raising the minimum purchasing age to 21, though 18-year-olds can still possess long guns. The National Rifle Association immediately filed suit to reverse the law, but it’s been upheld by the courts. California also raised the age to buy rifles, shotguns, and semiautomatic rifles to 21 in the wake of Parkland, but earlier this month, a federal appeals court ruled that the semiautomatic rifle provision was unconstitutional. Federal legislation to raise the minimum age to buy semiautomatic rifles to 21 was introduced in the Senate in 2019, but went nowhere. Two similar bills are currently stalled in the House.
In the wake of Parkland, Walmart and Dick’s Sporting Goods said they would no longer sell guns and ammunition to people under 21, and Dick’s removed military-style semiautomatic rifles from its Field & Stream-branded stores. Nine months later, Dick’s settled a lawsuit brought by a 19-year-old in Oregon, but the company did not change its policy.
Assault-style rifles have been used in some of the deadliest mass shootings over the last decade, including Sandy Hook in 2012; Pulse in 2016; Las Vegas and Sutherland Springs in 2017; El Paso in 2019; Boulder in 2021; and Sacramento on April 3 of this year.