Dick’s Sporting Goods has taken a hit to sales since announcing its new firearms sales policy, the company’s CEO said. (Rogelio V. Solis/AP)

When Dick’s Sporting Goods announced major changes to its firearm sales policies last month, the retailer was widely praised for taking action in the wake of the mass shooting at a Parkland, Fla., high school.

Two weeks later, Dick’s is worried sales could decline as a result.

During a conference call to discuss quarterly financial results Tuesday, Dick’s chief executive Edward W. Stack said it was too soon to fully grasp the effect of the retailer’s decision to stop selling military-style firearms and high-capacity magazines and limit sales to customers over the age of 21. But he was certain the impact on revenue would not be positive.

“Although the support has been overwhelmingly positive, there has been some negative pushback,” Stack said on the call with analysts and investors.

Stack noted that customers who buy firearms at Dick’s tend to buy other items as well, so the decision to stop selling one product had a wider effect.

“We knew that that was going to happen,” Stack said. “There were going to be people who just don’t shop us anymore for anything.”

The company says a sales decline in its hunting department could take a toll on its annual performance. Dick’s now projects same-store sales — a measure of sales at stores open at least one year — to remain flat, or fall, in 2018.

The announcement by Dick’s on Feb. 28 was spurred, in part, by the fact that the Parkland shooting suspect bought a shotgun from a Dick’s store in November. Even though that weapon was not the one used in the massacre that killed 17 people, Stack said at the time that “thoughts and prayers” were no longer enough.

“We did everything by the book, and we did everything that the law required, and he was still able to buy a gun,” Stack told “Good Morning America” host George Stephanopoulos.

Shortly after Dick’s changed its sales policies, Walmart and Kroger followed suit with new guidelines for the sale of firearms. The retailers joined a cascade of other companies that cut ties with the gun industry or the National Rifle Association after the Parkland shooting.

Lawrence Ring, a professor at the Raymond A. Mason School of Business at the College of William & Mary, cautioned against overestimating the effects of Dick’s new firearms policies on retail sales. Ring, who served on the board of the sporting goods superstore Sportmart in the late 1990s, said Dick’s is more likely to suffer from competition with Walmart, Bass Pro Shops or Amazon.com than from the consequences of its firearm policy change. (Amazon founder Jeffrey P. Bezos owns The Washington Post.)

“It’s really hard to show that [people] buy guns and buy basketballs,” Ring said. “Generally when people come to buy guns, they buy guns and bullets.”