For many years, you could walk into America’s most ubiquitous retail store and walk out with a military-style assault rifle. That will soon be impossible. Walmart announced this week that it will discontinue sales of “modern” sporting rifles, which are often fashioned to look like military weapons. It will also cease sales of any other gun that can carry high-capacity ammunition rounds.

The store claims the shift is a response to sales; a spokesman told Newsweek simply that “customers weren’t buying them.”

But there are serious reasons to question that justification, and instead to see a notable moment in evolving American views and standards on gun control.

Nationwide, gun sales are going up, not down, according to FBI data on background check requests. That’s the most reliable barometer of gun sales nationwide. While it doesn’t capture online sales or others where background checks are not required, Walmart does run them.

Analyses of the gun industry consistently show that assault rifles are a popular choice for consumers. The National Sports Shooting Foundation said in congressional testimony last year that there were 5 to 8.2 million assault rifles in the United States. Gun shop owners explained that if assault-rifle sales tail off at all, it’s because customers most likely owned one at some point. “The market is saturated. The market is flooded with them,” one gun merchant told USA Today late last year.

Walmart doesn’t report detailed sales numbers, and it’s possible there’s something idiosyncratic about Walmart gun customers that makes assault rifles unattractive. That would make them unlike gun customers nationwide—and Walmart is the country’s largest gun retailer, as we reported in detail in late 2012.

We also know gun sales are a big moneymaker for the retailer. A Walmart executive vice president told shareholders in 2012 that gun sales were a staple of improving sales numbers, and that gun sales increased 76 percent over the 26 previous months.

That’s all to say: Walmart’s explanation for stopping assault-weapons sales is not terribly convincing. More likely, the store is responding to increased concerns about gun control, and realizing that selling military-looking weapons three aisles over from diapers is untenable in a country where mass shootings continue to increase, and where more than half of shooters use assault weapons or high-capacity weapons. When I was working on the 2012 story, I contacted Walmart to request comment on the fact that they were selling the same gun Adam Lanza had just used during the shooting at Sandy Hook Elementary School in Newtown. The gun quickly disappeared from Walmart’s site, only to reappear later.

But Walmart executives had to be worried about another similar scenario—maybe even where the shooter buys their gun from Walmart directly.

People are often (and rightfully) frustrated with the lack of progress on gun control at the national level, but smaller victories at the state and municipal level are often overlooked. Several states from Washington to Connecticut instituted tougher gun laws since Newtown, and it’s become an increasingly potent message for big-city mayors.

This is the new reality Walmart is probably responding to—especially since the store’s new growth plan involves pushing into urban centers where, until now, there haven’t been many Walmart stores. (That may also explain Walmart’s quick decision to do away with Confederate flag products after the massacre in Charleston.)

Mayors often used Walmart’s gun sales as a reason not to approve a location, even if the company pledged not to sell weapons at that particular prospective store. New York City is even considering divesting from Walmart because of its weapons sales.

So while Walmart still remains the country’s largest gun retailer, their self-imposed assault-weapons ban can fairly be seen as a small victory for gun control advocates: It’s a new world Walmart finds itself selling in.