Freshman Rep. Tim Mahoney’s (D-Fla.) campaign got a boost Tuesday when the National Rifle Association endorsed him over his Republican challenger, attorney Tom Rooney.

In a race Roll Call has called a “tossup,” the endorsement could help Mahoney further shore up his conservative Democrat bona fides. He has already been endorsed by another Republican-leaning group, the U.S. Chamber of Commerce.

In a news release, NRA Political Victory Fund Chairman Chris Cox said the group gives Mahoney an “A grade for his work in Congress” on behalf of the Second Amendment right to bear arms.

Earlier this year, Mahoney signed on to a friend-of-the-court brief urging the U.S. Supreme Court to strike down a handgun ban in Washington, D.C.