Greg Evers announced the giveaway barely a week after a shooting at a gay nightclub killed 49 people in Orlando, which is about five hours drive from the Florida Panhandle congressional district Evers seeks to represent.
"With terrorism incidents on the rise, both at home and abroad, protecting our constitutional rights has never been more important," Evers said. "With all that's happening in the world today, I've never felt stronger about the importance of the second amendment in protecting our homeland than I do now."
The NRA says the second amendment to the U.S. Constitution gives Americans a broad right to bear arms. Advocates of stricter gun control say the amendment doesn't mean citizens should have the right to own assault weapons.
The custom-built AR-15 rifle, which the Evers campaign says is the "Homeland Defender" collector's edition, will be given away to one randomly chosen person who has liked and shared Evers' page or signed up on his campaign website.
The rifle was made in Santa Rosa Beach, Florida, and displays the Second Amendment on a metal plate on the right side near the trigger guard.
Evers added that the giveaway had been in the works and that an announcement had been held until now.
"I've always been a supporter of the Second Amendment. Terrorism and ISIS is a constant threat," Evers said, mentioning the Islamic State group.
Evers is one of five candidates running in the August 30 Republican primary for the seat being vacated by Republican Jeff Miller. Evers' chief rival is state Rep. Matt Gaetz, who has also received an A-plus grade from the NRA.
