Initiative 1491 would allow family members and law enforcement to petition a judge to temporarily suspend a person's access to firearms if the court finds that he is a threat to himself or others.
The "extreme-risk protection orders," modeled after domestic violence restraining orders, would require a court hearing and due process protections to remove guns from a person in crisis.
Opponents fear the protection orders could be misused by vindictive ex-partners.
The National Rifle Association's Institute for Legislative Action urged members, their family and friends to vote "no" on I-1491 in November.