Sales at Dick's Sporting Goods dropped in the past three months amid backlash against tighter gun-sale restrictions following a mass killing early this year at a Florida high school.

Revenue dipped 4.5 percent to $1.86 billion amid challenges in the company's hunting business during the quarter through Nov. 3. Sales at stores open at least 12 months – a key metric for the retail industry – fell 6.1 percent compared to the prior year.

Dick's raised the minimum age to purchase a gun to 21 and stopped selling AR-15 style rifles, also known as modern sporting rifles, last February. The decision followed a St Valentine's Day shooting in Broward County, Florida, that left 17 students and staff dead. The decision sparked opposition from conservative activists, some of whom had proposed arming teachers in response and threatened to boycott the brand, and prompted at least one employee to resign.

While Chief Executive Officer Edward Stack previously said the firearms policy brought in new customers and sales were reported as flat in August, Dick's has now warned that "negative reaction" could affect future results.

Despite lower sales, cost management and a higher margin helped the Pittsburgh-based sporting goods chain boost profit 2.5 percent to $37 million. Stack is investing in new bricks-and-mortar stores, opening six in the quarter, and bolstering the firm's e-commerce business, where sales climbed 16 percent.

"Our efforts have been focused on driving profitable sales and managing our business to deliver higher earnings," Stack said in a statement.

The company "accelerated freight coming in for January" in response to President Trump's tariffs on $250 billion in products from China and said it would, among other actions, raise prices on customers in 2019 to help mitigate the added costs. Trump has threatened to hike the tariffs from 10 percent to 25 percent and extend the levies to an additional $267 billion in imports.

Editor's note: This article has been amended to remove the term "assault rifle," which refers to a fully-automatic rifle or machine gun-type weapon that is tightly regulated by federal law and has never been sold by Dick's Sporting Goods.