Gun control efforts in California took a big hit on Thursday as the 9th Circuit Court struck down a state law requiring background checks to buy ammunition.

While some say this is a step back for gun safety, others believe this is part of common-sense gun laws.

The 2015 mass shooting at a San Bernardino County office killed 16 people, including both shooters who carried out the attack. The next year, California voters supported Proposition 63, which required background checks for those buying ammunition.

“To me, it’s peculiar,” said John Donohue, a Stanford Law Professor. “It really is a peculiar feature that these two federal judges are striking down the will of the people as well as the will of the California legislature.”

Professor Donohue feels the law made sense since roughly 400,000 guns were stolen last year.