STEVE INSKEEP, HOST:
It's a good time to be a gun-rights advocate. They've won victories in many states and the District of Columbia, making it easier to buy and carry firearms. Now a campaign has sprung up to ease restrictions on a different weapon - Chas Sisk has the story from Nashville, Tennessee.
CHAS SISK, BYLINE: This monthly gun and knife show at the Nashville Fairgrounds has just about everything a weapons collector could want - handguns and high-powered rifles, tomahawks and Tasers in colors that range from survivalist camo to hot pink. One of the bestsellers sits on the table of dealer Eva Simmons.
EVA SIMMONS: These are vintage switchblades from the '70s that I carry.
SISK: The kind with a black and silver handle and a Curly Q guard.
SIMMONS: It's just a one-button deploy, just like your regular switchblades that you see in "West Side Story."
(SOUNDBITE OF MUSICAL, "WEST SIDE STORY")
SISK: Gangs, street fights, Sharks and Jets. Knife enthusiast say that one Broadway musical gave switchblades a bum rap and took them off shelves for a generation. Blame Leonard Bernstein.
DOUG RITTER: Plays and movies like "West Side Story" fed the political hysteria to restrict these knives. There was never any rational basis for it, just as there isn't today.
SISK: That's Doug Ritter, an Arizona survivalist and knife designer. He's referring to a push that began in the 1950s when more than two dozen states banned knives associated with urban violence. Ritter is leading a knife-rights movement that's trying to repeal those laws. Seven states have done so since 2010, Tennessee became the most recent this past spring.
RITTER: The Second Amendment doesn't say firearms, it says arms. So why should people not be able to own the knives they want?
SISK: Knife crime has been on the decline for a decades. Last year, only 20 of the 337 murders committed in Tennessee involved knives. Terry Ashe, the leader of the Tennessee Sheriffs' Association, has a simple theory why.
TERRY ASHE: It's not as common as it was years ago because there are more guns now.
SISK: Still, police were cool at first to the idea of lifting Tennessee's ban on switchblades. Then lawmakers and knife rights activists compromised and made the penalties for knife crime tougher. Ashe adds, that when knives are used in crimes, switchblades are rarely the problem.
ASHE: Tons of knives at home that are all sizes, from steak knives to butcher knives, and most of the knife assaults you see actually happen in a domestic situation.
SISK: Knife advocates also argue switchblade laws are outdated. Tennessee's ban only applied to knives with internal springs. Manufacturers figured out a long time ago how to get around that restriction. Using other technologies, such as a lever, to open the blade.
CHRIS TENPENNY: And then just take your finger and just push that little flipper button on the back.
SISK: OK, great. Yeah, let me try that.
Chris Tenpenny owns a store called Nashville Sporting Arms. He says Tennessee's switchblade ban no longer made sense because most people couldn't tell the difference between a legal and an illegal knife.
TENPENNY: I've pulled out a knife before and I open it up, and somebody said oh, why are you carrying a switchblade? It's like, it wasn't even a switchblade, it was a regular knife. Yeah, there's just a lot of strange perceptions out there.
SISK: The easing of the laws has opened up the market for knives. When Tenpenny started four years ago, he carried fewer than 10 models, now he sells dozens of knives. They fill up two display cases and there are more piled up behind the counter - basic pocket knives Boy Scouts would use, a butterfly knife you might see in a Martial Arts film, high-end blades decorated with electric blue shocks with anodized titanium. But there's still one old-school weapon that you won't find on many shelves in Tennessee - brass knuckles. Those are still illegal, at least for now. For NPR News, I'm Chas Sisk, in Nashville. Transcript provided by NPR, Copyright NPR.