FAIRFAX, Va. — With gun sales plummeting after Donald Trump’s election victory, firearms manufacturers have set their sights on another way to boost business: a contentious proposal that would make the purchase of suppressors — more commonly known as silencers — easier and cheaper in the United States.

Trump hasn’t endorsed the bill but advocates — led by one of his largest campaign donors, the National Rifle Association — think they have found their most important ally in the fight: the president’s son.

Donald Trump Jr., an avid hunter who credits his Czech grandfather with getting him interested in the outdoors, headed up his father’s Second Amendment Coalition advisory group and counts himself a huge fan of the proposal, even pledging his father’s support in a video with the founder of the nation’s largest suppressor manufacturer, SilencerCo.

“I love your product,” Trump Jr. says in the 38-minute video interview with SilencerCo CEO Joshua Waldron, which was recorded before the election. “It’s just a great instrument. There’s nothing bad about it at all. It makes total sense. It’s where we should be going.”

Supporters say the bill introduced in the House of Representatives and the Senate — named the Hearing Protection Act — would guard the hearing of millions of hunters who don’t use earmuffs or plugs to shield their ears from their guns’ loud reports, which have been proven to cause hearing loss.

Opponents say, however, that reducing the sound is dangerous because potential victims won’t know to run or hide from shooters if they can’t hear the firing. They say making silencers easier to buy would benefit urban street gangs, whom quieter gunshots would allow to escape quick detection.

Trump Jr. did not respond to messages left at the Trump Organization, the family business he now runs with his brother Eric.

Donald Trump Jr. is a member of the Boone and Crockett Club, a hunting group founded more than a century ago by Theodore Roosevelt and named for Daniel Boone and Davy Crockett. He was photographed with his brother with dead animals — including an elephant, or at least its tail — on a hunting trip to Zimbabwe. And he helped his father select a secretary for the Interior Department, which manages lands, wildlife and national parks.

Silencers aren’t as effective in real life as the ones portrayed in James Bond movies. They may reduce the noise of a gunshot by an average of 20 to 35 decibels — similar to wearing earmuffs or earplugs — but the sound can still be as loud as a jackhammer, according to multiple studies. Hearing damage can still occur with a silencer, and shooters are encouraged to wear hearing protection while using them.