After the mass shooting at Sandy Hook Elementary School in 2012, Congress stalled on passing gun control laws. Any efforts to curb ownership of assault-type rifles, like the AR-15 used in Newtown or the SIG Sauer MCX reportedly used last weekend in Orlando, also failed.
But that didn't prevent some states from taking action.
Less than a month after the Sandy Hook shooting, New York's legislature passed the Secure Ammunition and Firearms Enforcement (SAFE) Act, which banned the sale of new or used AR-15s, as well as other rifles with military-style features, including high-capacity magazines.
"People constantly say, oh, nothing's ever changed, we're at a complete stalemate on guns . And if you only look at Congress, that's right," says Adam Winkler, a law professor at UCLA.
The national ban on the sale of rifles like the AR-15 and the SIG Sauer MCX expired in 2004, and it hasn't been renewed.
"But since Newtown, we've seen a wave of legislation at the state level, including restrictive new laws in California and Washington, Oregon, Colorado, New Jersey, Maryland, New York, we can go on and on," Winkler says.
Winkler, who wrote a book on the gun control debate called Gunfight: The Battle Over the Right to Bear Arms in America, says about half of Americans now live in states where gun laws have tightened significantly the last few years.
That doesn't mean that AR-15-like guns have disappeared in these states, though. People who owned the weapons before the sales ban went into effect were allowed to keep them — they were grandfathered in, if they registered their rifles with state police. More than 45,000 New Yorkers are now in the state's assault weapon database.
Where gun laws are more permissive, such as Florida, AR-15-style guns have sold big.
"They've become extremely popular," Winkler says. "People who are gun hobbyists, who go to the shooting range every weekend, they love these firearms."
No one keeps accurate records of the total number of these firearms now in civilian hands. One industry group estimates that 1.5 million guns with military-style features are sold in the U.S. every year.
Some gun owners, like Steve Bizell of New York, are trying to figure out how they can beat the new state restrictions.
"It says sale of assault weapons banned in New York, so what if I go to Vermont and buy one and bring it into New York?" Bizell asks. "So I'm dead in the water. I could never have an assault weapon."
For Second Amendment activist Bob Schulz, that's a problem. Despite these mass-shootings, Schulz said weapons such as the AR-15 keep people safe.
"You know, what match does a homeowner have with a handgun against two, three, four people who decide to invade?" Schulz says.
Schulz, who sued unsuccessfully to overturn the SAFE Act, worries that mass-shootings might prompt other states to follow New York's lead.
"We could go too far," Schulz says. "This could be a very slippery slope."
There are currently no good studies, or clear data, on whether these state-level gun laws make people safer. The CDC is still prohibited from conducting research on gun violence.
New York Gov. Andrew Cuomo, who passed the state's gun control law, wants Congress to act and fill in the gaps.
"It does us no good as a state to outlaw an assault weapon when someone can get in a car and drive three hours to another state and buy it and drive it over our border," Cuomo said at a rally this week outside the Stonewall Inn, an LGBT landmark in New York City. "Until we have a national policy, none of us are safe."