It is now illegal for people under 21 to purchase semiautomatic assault rifles in Washington state.

The ban, part of a ballot initiative approved in November by 59 percent of Washington voters, raises the minimum age limit from 18.

“It is a meaningful step in the right direction,” said Christian Heyne, legislative director at the Coalition to Stop Gun Violence. “Gun violence on the whole is such a complex problem. We need to have complex solutions, comprehensive solutions. This is a part of that conversation.”

Additional rules included in the ballot measure will take effect in July and will require gun dealers to wait 10 days before delivering semiautomatic assault rifles in an attempt to minimize spontaneous actions. The measure also requires people who purchase a semiautomatic assault rifle also to have gone to gun safety training within the prior five years, among other requirements.

The National Rifle Association has filed a lawsuit arguing the restrictions are unconstitutional.

[Also read: Commission investigating Florida school shooting recommends arming teachers]