An advocacy group, led by family members of people killed in the Clackamas Town Center mass shooting, is proposing a ballot measure that would require gun owners to lock away their guns while not in use and mandate people report lost or stolen firearms to law enforcement within 24 hours.

If it makes it to the November ballot, the initiative sponsored by Oregonians for Safe Gun Storage could be one of two possible gun control measures before voters in the fall. The other would ban the sale of assault weapons.

Ballot measures need to be supported by 88,184 signatures by July 6 to be placed on the official ballot.

"Today marks a critical step to reducing gun violence in Oregon," Gun Owners for Responsible Ownership PAC leader Jenna Yuille said in a statement announcing the measure. "Establishing clear standards for responsible firearm storage will save lives. Unsafely stored firearms pose an immediate danger. People who gain unintended access often cause harm to themselves and others."

Yuille and co-petitioner Paul Kemp both had family members who died in a 2012 shooting at the Clackamas Town Center.

The measure is one of several recent attempts to further regulate gun ownership. Several local and national retailers have either discontinued firearm sales or raised the minimum age to buy a gun to 21. The Oregon Labor Commissioner Brad Avakian vowed to propose legislation to formally raise the minimum age to buy guns or ammunition to 21.

Some gun owners have pushed back against these restrictions with discrimination complaints under Oregon law, which protects people from discrimination based on age.