The AR-15 has been called “America’s rifle,” a weapon emblematic of our national gun culture. But a new survey finds that in the country’s most populous state, a small contingent of hardcore collectors own the vast majority of ARs and other so-called assault rifles.

The research, published by the Violence Prevention Research Center at the University of California-Davis, found that four out of five assault rifles in the state are owned by people who own 10 or more guns. In total, the results suggest Californians own nearly a million assault rifles — or about 5 percent of all guns in the state. That’s roughly in line with national estimates of gun ownership.

The findings are the product of a broad survey of Californians and their relationship to guns. Among the survey’s other key findings: 25 percent of gun-owning respondents said they had purchased a firearm without going through a background check. California has required checks on all gun sales or transfers since the early 1990s.

In regards to assault weapons, respondents were asked whether they own a “rifle of the type sometimes called ‘assault rifles’, ‘modern sporting rifles’, or ‘modern tactical rifles’, including AR rifles, AK rifles, and SKS rifles.”

California law employs a narrower, more complicated definition: Any semiautomatic, centerfire rifle with that can accept a detachable magazine and has any one of several features, including a pistol grip or flash suppressor. The state also has a list of hundreds of weapons — many of them AR and AK variants — that are expressly labelled assault weapons. California law forbids the sale of new assault weapons and requires all existing ones to be registered with the state Department of Justice.

In response to the state’s assault weapons regulations — considered among the most stringent in the nation — many manufacturers offer so-called “featureless” or “California legal” versions of AR-15 or AK-47 rifles. These models often come with magazines locked in place, or creatively designed grips.

“California legal” guns aren’t subject to the state’s assault weapons law, but they would count for the purposes of the researchers’ survey. As a result of the discrepancy, the total number of assault weapons registered with the California Department of Justice is far lower than the total suggested by the survey. As of this July, Californians had registered or applied to register 226,388 guns.

The researchers conducted the survey online this October, questioning 2,500 state residents over the age of 18.

The researchers noted that people who said they owned assault weapons were demographically distinct from the rest of the population of the young, diverse state: 69 percent of assault weapon owners are over 45 years old, 84 percent are male, and 67 percent are white.

Past surveys of gun ownership have not asked who owns this particular controversial subset of weapons. The National Firearms Survey, released in 2016 by public health researchers at Harvard and Northeastern universities, was the most comprehensive national look at which Americans own which guns, but it only asked about whether respondents owned handguns or long guns — not specific models or styles within those category.

Without comprehensive data on assault rifle ownership, there’s no way of knowing exactly how many people own the weapons, which occupy a central place in debates over American gun violence and policy. But the survey released this week suggests a group of so-called super-owners may be fueling the demand for AR-15s and their counterparts, not the public at large.