Greg Apple is selling a lot of semiautomatic rifles.

Customers wandering through the Collectors West Gun and Knife Show last weekend pause to look at his 10-yard-long display of rifles, priced as low as $499. 

The guns on display at the Portland Expo Center are various models of the AR-15, the military-style rifle that one gun lobby says is "among the most popular firearms being sold.” 

The 41-year-old Apple sips a Pyramid beer and urges people to buy now. The state of Oregon or President Obama, he says, could ban these guns in a matter of days.

“I can’t guarantee that any of this will still be available on Monday,” he says. “You gotta get ’em while you can.” 

The pitch works like some kind of dream.

Two mass killings—the shooting in Clackamas Town Center on Dec. 11 and the slaughter of schoolchildren and educators in Connecticut three days later—have shocked the country.

But the national cascade of grief has had an inverse effect on buyers at the Portland gun show: The more horrified the nation became as news spread about Friday's shooting in Connecticut, the more heated the sales of guns—especially the AR-15.

"This is the busiest year in show history, from what I've heard from other sellers," says Apple, who works for Northwest Armory.

Police say both shooters last week killed their victims with AR-15-style semiautomatic rifles. So did the man who opened fire in a Colorado movie theater during a Batman premiere in July. So did the Beltway sniper 10 years ago, and the man who shot a ranger in Mount Rainier National Park last New Year's Day.  

The latest attacks have sparked calls around the country for a ban on these rifles. Gun-control group Ceasefire Oregon has signed at least 17 state legislators to co-sponsor an assault weapons ban. State Sen. Ginny Burdick (D-Portland) says she'll introduce a bill to outlaw sales of gun magazines that can hold more than 10 cartridges.

WW wanted to hear from the people who want these guns—and the people busy selling them. So we spent three days at the gun show and found Portland was seeing a run on these semiautomatic rifles in another kind of spree.

"There's a lot of first-time buyers," says Rob Heller, owner of Tactical Ammunition in St. Helens. "People are worried about people taking their guns away."

Shoppers entering the Expo Center pass by a gun-check table. Many patrons have hunting rifles slung over their shoulders. Others are carrying concealed weapons. But no loaded guns are allowed.

"If you hand me a loaded gun," a neon green sign on the table reads, "I KEEP THE AMMO!"

Inside the 72,000-square-foot hall, men holding clear plastic cups of Coors Light browse the vendor booths. Of the roughly 5,000 people in cavernous Hall D, about 95 percent are male.

More than 150 vendors have laid out their wares in 12 long rows as part of the gun show, held at the Expo Center about every two months.

The gun show serves as an outing for fathers and sons. Repeatedly throughout the day, dads affectionately squeeze their young sons' shoulders as they gaze at the tables of weapons.

One father at the Northwest Armory counter is buying three AR-15-style rifles with his son, who looks about 6. The kid complains of boredom.

"You're at a gun show," the father says reproachfully, "surrounded by weapons, and you're saying you're tired."

The shooting of 6- and 7-year-old children in Newtown is discussed obliquely within the Expo Center. The first reaction voiced usually isn't shock, but a defense that it wasn't the fault of guns. 

Repeatedly, people bring up an attack on an elementary school in China where the assailant used a knife. 

"Cut up a bunch of schoolkids," says a man in a maroon hunting jacket washing his hands in the bathroom. "And they try to tell us this country's full of crazies."

No one mentions that none of the children in China died.

Most people have business on their minds. A woman overseeing about eight tables of guns is asked Friday how her day is going.

“Could be better,” she says. What’s wrong? The credit card machine isn’t working. “They say it’s too much metal in the room.” 

Pistols, Glocks, shotguns, pink-barreled rifles, and 50-year-old pearl-handled Derringers—the choices stretch on. Shoppers can also buy camo-colored crossbows, freeze-dried peach slices, yellow plastic gold-panning buckets, swastika-emblazoned poker chips, potassium iodide anti-radiation tablets, and fudge.

One stand sells zombie torsos and heads made of biodegradable material filled with red paint. One looks like a zombie Osama bin Laden, a bullet hole in his cheek.

The demand for guns grows. On Saturday morning, one gun salesman, Nick Miller, warns customers to expect delays. The usual 30-minute wait for the Oregon State Police to conduct a mandatory background check before a sale is getting longer because of the demand.

"The background check's probably going to take 45 minutes," Miller says, "so you probably want to start the paperwork now."

By midafternoon, the wait will balloon to as long as three hours.

And the biggest draw is the AR-15. 

Miller, 23, sells rifles and handguns for his family's business, Oak Grove Guns. His father is also a contractor, and the Millers own two Eugene farms with 60 miniature horses. "I can build you a house and barn," Miller says, "I can sell you the horses, and I can sell you the gun to defend the house and horses."

Since the recession started, Miller says his family has turned more to gun sales. He's happy to explain the allure of the AR-15, which he both owns and sells.

"Honestly, the appeal is that it's a military gun," he says. "The military has it, so people want it."

Invented in 1957 by a California weapons company called ArmaLite Inc., the AR-15 rifle was bought by the U.S. military, while an automatic model became famous as the M-16. The commercially available AR-15 is semiautomatic, which means the gun requires a trigger pull to fire each shot but mechanically loads a new cartridge in the chamber.

The rifle is also popular because it's endlessly customizable, Miller says, with thousands of accessories from scopes to flashlights. "You can turn it into something that can literally do any job," he says. "You can hunt bears with the dang thing with the proper bullet."

Miller volunteers that there's no practical justification for high-capacity gun magazines that hold more than 10 rounds.

The only reason people want them, he says, is to fight an invading army on U.S. soil.

"I'm not paranoid, so I don't think we're going to be invaded," Miller says. "That being said, I do think it is a deterrent. It's a comfort to know that if any government came knocking on your door, ours or otherwise, you'd have a way to stop them."

A nearby shopper, 27-year-old Andrew Dixon of Beaverton, bought his first AR-15 two weeks ago.

"They're the most fun to shoot," Dixon says. "You can shoot them up to 200 yards. And there's a bunch of attachments. You can customize 'em to you. It's just endless what you can do with it. It's the ultimate gun toy. I can't really explain."

One vendor, a skinny 18-year-old named Shane Neal, who enjoys firing the AR-15, tries to describe it.

"You feel like a boss," he says, grinning. "It just feels cool."

Greg Apple's sales pitch is paying off. 

By Saturday night, he estimates his employer, Northwest Armory on Southeast McLoughlin Boulevard in Milwaukie, has sold $40,000 worth of guns.

"People are still coming in," Apple says Sunday afternoon. "Everybody's paranoid, buying things at the price they're at now, instead of having to pay a lot more later."

Apple began working part-time at the Gun Broker in Tigard around 2008, while still a swing-shift supervisor at Advance Machining in Newberg. Then the machine shop ended its swing shift, and he became a full-time employee at Northwest Armory, where he can get health insurance.

Apple says he tries to educate gun buyers about firearms safety—but last week's shootings have not given him pause.

"How could I be responsible if they're on certain meds, or [for] their intelligence level?" he says.

Northwest Armory's tables feature semiautomatic rifles—models by Colt and Ruger, and a Smith & Wesson 15-22 zebra-striped in hot pink. Several shoppers say they already own an AR-15-style rifle and hadn't considered buying more until the Clackamas Town Center and Sandy Hook shootings.

"No intention of getting another one until this shit happened," says 18-year-old Nick Vanaken of Forest Grove, who buys a Core 15 .22—another AR-15 model—for $900. It's his third semiautomatic rifle. "Came back today because I figured our rights are going to be gone pretty soon."

"That, and people doing stupid shootings," says his friend Eric Schliebe, 19. "They ruined it."

By Sunday night, Miller is one of several dealers who have sold out of AR-15 model rifles. He thinks the rush to buy semiautomatic weapons is just another fearful tizzy, like the spike in gun sales after President Obama's 2008 election.

Nothing happened then, he says. And nothing will happen now. 

"Everybody's going to flip out for two or three days," Miller predicts. "And then we're all going to calm down, because Lindsay Lohan's going to get another DUI and we're all going to move on."