What do an elderly Oklahoma homeowner, a Virginia Citizen Militia member, and a Texas airline pilot all have in common these days?

They're all part of America's massive gun-and-ammunition buying spree – a national arming-up effort that began before last year's election of President Obama and continues unabated. Across the United States, it has led to shortages of assault-style weapons, rising prices, and a broadening of gun culture to increasingly include older Americans, women and – gasp – liberals.

The causes are varied – from fears over crime, both rational and irrational, to the concern that Second Amendment rights will be curtailed by a Democrat-controlled Washington. With the stock market deeply uncertain, some buyers simply think guns are a good investment. The run on guns suggests a shift in public attitudes about gun rights, and it presents a snapshot of a country that has historically turned to powder and balls in times of turmoil.

"There's the sort of stereotype that gun owners were middle-aged Republican white men who were fairly easy to isolate ... in order to regulate them out," says Brent Mattis, a shooting instructor in Florida. "Now that more women are owning guns, more liberals are owning guns, and just average everyday people who want to keep themselves and their family safe. It's turning into an incredibly strong political phenomenon."

This is most evident on store shelves. Select types of ammunition – ranging from the .308 caliber typical in self-defense guns to the .223 caliber usually associated with assault-style weapons – are nearly impossible to get in many parts of the country. Prices are up by more than half over last year. Assault-style weapons are back-ordered for months. Springfield, Mass., gunmaker Smith & Wesson is one of the few brights lights on Wall Street, its stock price up by 70 percent on the year. A few weeks ago, the gunmaker took orders of over $9 million in one day.

The FBI is hiring extra processors to deal with a glut of background checks that have increased by 25 percent year to year every month since November – a good indicator of sales. In the wheat-and-cattle corner of Oklahoma patrolled by Sheriff Bill Winchester, concealed-carry permit applications are up by 300 percent, including a request by an elderly man whose hands were so unsteady that he could barely scribble his name.

"There's just so many people that would never have knocked on our doors before that are now coming in," says Bob Roddy, a longtime clerk at Chuck's Firearms in Norcross, Ga., outside Atlanta. "There's a level of desperation which I don't ever recall seeing before."

It is not uncommon for gun and ammunition sales to cycle, sometimes dramatically. They spiked after the election of Bill Clinton in 1992, for example. Mr. Clinton had promised more gun control, resulting in the 1994 assault weapons ban (which expired in 2004). Mr. Obama, for his part, hasn't made any overt gun- control gestures. To the contrary, he has expounded on his support for the Second Amendment. Even recent court decisions are in gun owners' favor: The Supreme Court upheld the right of homeowners to keep handguns for self-defense in the so-called Heller decision last year.

Some gun-control advocates are bewildered by the uptick. "We find [it] disconcerting," says Juliet Leftwich, legal director for the Legal Community Against Violence in San Francisco.

Yet gun owners see some worrying signs. One proposed bill in Congress would mandate microstamping on bullet cartridges in an attempt to help law enforcement officials more easily track bullets used in crimes. But it also has the potential to raise prices and outlaw home reloading shops. South of the border, the pitched narco-war battles, partly fueled by US-bought military-style weapons, has brought renewed calls for regulation from gun-control advocates.

The buying trend, however, is far deeper and more prolonged than any knee-jerk reaction to an election or potential legislation, experts say. Though liberals still favor gun control at far higher percentages than conservatives, Americans as a whole are edging in the direction of more gun rights, according to a recent poll by Rasmussen Reports, an independent polling firm in New Jersey.

A major piece of the shift is the perception among many Americans that crime is rising rapidly. Nearly a third of Americans surveyed in the Rasmussen poll say crime has increased in their neighborhoods, and 72 percent say it's very likely that crime will grow in the near-term.

The FBI reported in January that, nationwide, violent crime was down 3.5 percent in 2008, robberies were down 2.2 percent, and car thefts declined by 12.6 percent. Those statistics contrast with 2006, when robberies, for example, jumped by nearly 10 percent.

The fears are in some cases taking on a Y2K-like fervor, forecasting total social meltdown. In times such as these, Americans have always reached for their guns, says David Kopel, research director for the Independence Institute, a free-market-oriented think tank in Golden, Colo. He digs up a clipping from a Massachusetts newspaper published three months before the "Shot Heard Around the World" that started the Revolutionary War. The article documented a vast gunpowder shortage blamed on "wolves and other beasts of prey" lurking about. Modern fears are fueled by the prospect of an apocalyptic economic failure.

"The logic is simple," says Tom Lee, a member of the Virginia Citizen Militia, which traces its roots to the Revolutionary War. "People are seeing a looming economic collapse that will lead to a prolonged and possibly worsening breakdown of law and order and, eventually, a We-the-People vs. armed-government-enforcers scenario. I'm sure I'm not the only one who sees through the Keynesian scam and sees the wisdom in preparing for the worst."

In Missouri, state police recently sent out a report on militia activity warning officers to be suspicious of, among other things, cars with Ron Paul bumper stickers. (The state subsequently removed references to politicians and political parties in response to an outcry.)

But while total numbers of guns sold is up in the US, some Americans wonder if the buy-up isn't more tied to business potential than fears of upheaval. Airline pilot Jim Hamilton, a member of the newly formed Liberal Gun Club in Dallas, describes watching a businessman in a red golf shirt and Dockers pants emptying a whole shelf of .45 caliber ammo into a shopping bag at a gun store.

"He had every intention of cleaning off the shelf, and he looked up at me and smiled like a kid with his hand in the cookie jar," says Mr. Hamilton. "I was expecting stockpilers to be kind of the ex-military guy in 'camo' burying it in his backyard for a zombie invasion. Now, I'm inclined to believe that people are not stockpiling for self-defense or civil unrest, but as an investment. Maybe they're not as worried about political issues as turning a profit."

Mr. Winchester, the sheriff in Enid, Okla., has the same thought. "Guns have always been a good investment," he says. "Guns are as good as gold."