Gun rights advocacy groups are challenging Maine's 72-hour waiting period for gun purchases, arguing that it’s unconstitutional.

A coalition of Maine gun rights groups is challenging a law requiring a three-day waiting period to purchase a firearm, a measure that took effect in August. It is one of several gun safety bills state lawmakers passed following the Lewiston shootings that killed 18 people.

A coalition of gun rights groups is suing Maine over a law requiring a three-day waiting period to buy a firearm, arguing that the new requirements violate the Constitution. The lawsuit, filed in U.S.