The backlash was swift, and fierce. Readers threatened to cancel their subscriptions. Death threats poured in by email. His television program was pulled from the air.
Just days after the column appeared, Metcalf said, his editor called to tell him that two major gun manufacturers had said "in no uncertain terms" that they could no longer do business with InterMedia Outdoors, the company that publishes Guns & Ammo and co-produces his TV show, if he continued to work there. He was let go immediately.
"I've been vanished, disappeared," Metcalf, 67, said in an interview in December on his gun range here, about 100 miles north of St. Louis, surrounded by snow-blanketed fields and towering grain elevators. "Now you see him. Now you don't."
He is unsure of his next move, but fears he has become a pariah in the gun industry, to which, he said, he has devoted nearly his entire adult life.
His experience sheds light on the close-knit world of gun journalism, where editors and reporters say there is little room for nuance in the debate over gun laws. Moderate voices that might broaden the discussion from within are silenced. When writers stray from the party line promoting an absolutist view of an unfettered right to bear arms, their publications - often under pressure from advertisers - excommunicate them.
"We are locked in a struggle with powerful forces in this country who will do anything to destroy the Second Amendment," said Richard Venola, a former editor of Guns & Ammo. "The time for ceding some rational points is gone."
There have been other cases like Metcalf's.
In 2012, Jerry Tsai, the editor of Recoil magazine, wrote that the Heckler & Koch MP7A1 gun, with ammunition designed in part to pierce body armor, was "unavailable to civilians and for good reason."
He was pressured to step down, and despite apologizing, has not written since.
In 2007, Jim Zumbo, by then the author of 23 hunting books, wrote a blog post for Outdoor Life's website suggesting that military-style rifles were "terrorist" weapons, best avoided by hunters. His writing, television and endorsement deals were quickly put on hiatus.
Garry James, a senior editor at Guns & Ammo, said in a phone interview several weeks ago that its readers were the magazine's main concern and its editorial independence was not at risk. But, he added, "advertisers obviously always have power, and you always feel some pressure." He declined to discuss Metcalf's matter specifically, and the company did not respond to further phone calls and emails seeking comment on other aspects of the operation.
Metcalf said he was told that advertisers feared customers would boycott their products if they continued to advertise on TV shows and magazines featuring his work.
Two major advertisers with InterMedia are the gun companies Ruger and Remington Arms Co. Ruger's general counsel, Kevin B. Reid Sr., said in an email that it did have a conference call with InterMedia to discuss the column, but that it was informed "that the decision had already been made to part ways with Mr. Metcalf." He denied Ruger pressured InterMedia to fire Metcalf.
A spokesman for Remington did not respond to messages seeking comment.
Editors of gun magazines are unapologetic in acknowledging that their content caters to the gun enthusiasts who believe their rights are under constant threat, and to the firearms companies that account for much of their revenue. At some magazines, said Jan Libourel, a former editor of both Guns & Ammo Handguns and Gun World magazines, "the editors only want editorial content for some key advertisers."