Fleet Farm quietly changed its gun marketing last month.

The retailer stopped all advertising and promotions for assault-style rifles and high-capacity magazines but it will continue to sell them, Derick Prelle, Fleet Farm's chief executive, said in an e-mail interview.

"In response to customer input, we made the ad decision a month ago," he said. The policy was fully implemented through March, he said.

Other gun sellers such as Dick's Sporting Goods, Walmart and Fred Meyer quit selling assault-style rifles and high-capacity magazines and raised the age limit for anyone purchasing guns or ammunition to 21. The larger magazines allow for multiple ammunition rounds, in some cases 20 or more, to be fired without reloading.

Fleet Farm also changed its background-check policy. Currently, federal law allows a sale to take place if the gun seller receives no response from the FBI within three days. Fleet Farm changed its policy so that "no sale will occur unless we receive a positive 'OK to sell' response from the FBI."

Typically, when federally licensed firearms dealers request a background check of a prospective purchaser, they get one of three answers — approve, deny or further review. If the dealer doesn't hear an answer within three days, even if it's under further review, they tend to assume it is OK to sell to the customer.

In Minnesota, prospective buyers of semiautomatic assault-style rifles from a federally licensed dealer must also obtain a permit to purchase from a local police department or sheriff's office.

To ensure 100 percent compliance with its new background policy, the company instituted a software change that provides an extra layer of security. Prelle said the extra security should be in place within the next few weeks.

Companies that have made changes to their gun policies do not always make them permanent. After the Sandy Hook shooting in 2012, Dick's halted sales of assault-style rifles but then started selling them at its Field & Stream stores a few months later. When asked on "Good Morning America" at the end of February if the company might later start selling assault-style rifles again, Chief Executive Ed Stack said, "We have eliminated these guns permanently."

Several retailers that sell guns have not made recent changes, including Bloomington-based Gander Outdoors, Cabela's and Bass Pro Shops.

Although the company still uses the name "Mills Fleet Farm" in its advertising, the Mills family no longer has significant involvement or ownership. More than a year ago the Mills family sold the firm to KKR, a New York investment firm, for a reported but unconfirmed $1.2 billion.

John Ewoldt • 612-673-7633