The Wyoming sun has just begun to set when Stuart Ruben opens up on the mini gun.

In 15 seconds the powerful weapon spews out 1,000 rounds of tracers, incendiary bullets and starburst ammunition. It's not exactly a subtle gun. Onlookers standing nearby feel, rather than hear, it fire.

Moments later, hundreds of shells casings lie at Ruben's shoes and an old sedan several hundred feet away bursts into flames.

The voice of range safety officer Bill Black booms over the loudspeaker.

"The line is hot, the line is hot. Everybody may start shooting now."

All along the firing line, dozens of people are shooting at targets set up on an empty prairie about 30 minutes south of Casper. They're participating in the North Rockies 10th annual Machine Gun and Cannon Shoot - a three day gathering of gun enthusiasts who enjoy the type of firearms you can't buy at Wal-Mart.

That includes World War II-era machine guns, 100-year-old cannon and mini-guns that can reduce a car to a pockmarked shell in a matter of seconds.

"Once you go to one shoot, you kind of get hooked on it," says Black, who's wearing a camouflage jacket and binoculars as he stands on a tower overlooking the range.

Below him, the shooters are firing at a variety of targets: empty propane tanks, old vehicles and even photos of Osama bin Laden.

Still, there's much more to the gun shoot than blowing things away with automatic weapons, participants say.

"I've always been a gun enthusiast," says John Sweeney, a Kemmerer man who works as an airline pilot. "What fascinates me are the mechanics of them."

Sweeney brought along six guns to the shoot, including a .50-caliber Browning machine gun and a Russian 1910 Maxim, which fires in the neighborhood of 600 rounds a minute.

Standing nearby, Sweeney's friend Dave McConkie explains that the historical nature of the weapons is a key draw of the shoot.

"It's not so much the shooting of the gun," he says. "It's the history of it."

Of course, for some, the attraction is more visceral.

"I love to shoot," says Gillette resident Brian Hamilton, as he sorts ammunition during a break in the action. "It's just a good time. Good people out here."

The backgrounds of those people run the gamut, from doctors to ex-military to woodworkers and even students.

"We are like everybody else," says Sweeney. "We just enjoy ourselves in a different way."

The gun shoot is sponsored by the Wyoming NFA Shooters Club, Inc., an NRA-affiliated gun club that's been in existence since 2003. Proceeds from the event benefit the Casper Mountain Volunteer Fire Department.

Although many of the guns at the shoot are more powerful than the typical firearm, they are all legal, says Ruben, who organized the event. Weapons like a mini-gun or Browning must be registered, and the owner must undergo a background check and an interview with the chief law enforcement officer in the area.

"This is not something that is secretive," Ruben, a Casper doctor, says. "It's not something we have ulterior motives about performing."

The weapons aren't cheap either. Some of the guns on the firing line cost $40,000, says Curt Lund, a South Dakota gun dealer who planned to spend the weekend at the shoot.

As the sun fades, 18-year-old Natalia Wilkins picks off targets with her AR-15 rifle. A red-haired teen with braces, she's one of the few women on the firing line. At age 10, Wilkins started attending shoots like this with her father.

"I kind of got hooked," she said. "It's all because of the .37-mm cannon."

Firing that cannon led to an interest in other weapons. The AR-15 is now her gun and she hopes to have other firearms someday.

"I like the accuracy and skill it requires to shoot and shoot well," she says, as gunfire crackles and booms in the background. "It's something that can be a lot of fun."

Reach Joshua Wolfson at (307) 266-0582 or at josh.wolfson@casperstartribune.net.