Rep. Ken Buck (R-CO) tweeted a photo last week of him and Rep. Trey Gowdy (R-SC) posing with an American flag-patterned AR-15 rifle in a show of their Second Amendment bona fides.

Unfortunately for Buck, a Washington, D.C. attorney general’s office spokesperson told The Hill that it’s illegal to possess an AR-15 in the District. The spokesperson told the publication that the matter had been referred to the Metropolitan Police Department.

Buck told The Hill that Capitol Police approved of him bringing the rifle into his office, where he said he keeps it locked in a display case. He also said the firearm was “inoperable.”

“While safety protocols call for all guns to be treated as if they are loaded, this one isn’t,” he told the publication. “Further, a close inspection of the only public photo of the rifle will show that the bolt carrier assembly is not in the rifle; it is in fact in Colorado.”

“It is a beautiful, patriotic paper weight,” Buck added.

Earlier this year, the right-wing blogosphere cried foul after the conservative blog Legal Insurrection published evidence that police in the District had wanted to arrest David Gregory, the former host of NBC’s “Meet The Press,” for holding a gun magazine on-air in 2013. The attorney general’s office ultimately declined to prosecute Gregory.