Karla Wagner lives in Marietta, but wearing a cowboy hat, chaps and double gun holster, she looks like she came straight from the Wild, Wild West.

And not only is the 15-year-old cowgirl skilled with a .45 caliber revolver, but she can shoot her target while she's on top of a galloping horse.

"You have to be able to ride pretty well," Karla said. "You have to have good concentration."

This past weekend more than 75 cowgirls and cowboys dressed in western wear brought their horses and revolvers for the Peach State Mounted Shooters monthly competitions. They drove their trailers to the Chicopee Woods Agricultural Center main arena in Gainesville, where the gunshots were loud and so was the cheering.

Organized mounted shooting has existed for nearly 20 years now, and it's popularity is on the rise.

"It's the fastest-growing equestrian sport there is," Peach State Mounted Shooters president Robert Derry said.

Mounted shooting involves a course with balloons, cones and a barrel. Riders gallop their horse through the course as fast as possible and attempt to shoot each of the 10 balloons.

There's a different course for each of the four stages, chosen randomly. Riders don't know what courses they'll be riding until the day of the event. And there's no time to try out the course before competing.

It's harder than it sounds. Karla has ridden horses since she was 9, and she's navigated courses and shot at balloons for the last two years.

"You try and do it the fastest way possible that will let you be able to shoot them all," she said.

Riders earn points for their speed and lose points when they miss balloons or deviate from the course.

Karla said the first course of Sunday's "Great Balloon Hunt" was pretty challenging.

Wearing their chaps, cowboy hats and holsters, riders galloped off and easily shot the first two red balloons, which were one after another and spaced well apart. The difficulty came with the next three targets, placed in a triangle pattern close together. Riders had to come to a near halt, shoot all three balloons, and perform a rapid gun switch while rounding the barrel for the next targets.

Riders must carry two guns to shoot all 10 balloons, and switching guns can prove difficult, particularly with Sunday's first course, Karla said.

"This one's a really fast gun change," she said.

Karla enjoys complicated courses. The horse she borrows, Prissy, follows her commands well, even when the course is challenging.

"It's fun leading your horse the right way. It's like a feeling of accomplishment when you've done something hard," she said.

The cowboys and cowgirls are of all ages, and the youngest riders complete the course without guns.

Nine-year-old Kayla Lewallen, of Trinity, N.C., loves competing with her pony, Ginger, in the "limited wrangler" class.

"You're traveling all over, meeting new people, making new friends," she said.

When Kayla turns 10 she'll be allowed to use a toy gun, and eventually a real gun as she gets older.

She plans to practice when school is out this summer.

Spectator Brandon Rion of Commerce, who recently began riding, was rather impressed with the mounted shooters.

"I just haven't actually seen someone shoot a gun and ride horses," the 10-year-old said, "It's really amazing."

Brandon came to the event with his sister, who is part of the horse club of the Jackson County 4-H.

They, along with the Hall County 4-H, use the event as a fundraiser, earning up to $,1000 a weekend each for helping replace balloon targets.

"We try to do a real good job at getting balloons," Jackson County 4-H program coordinator Penni Tench said.

Safety is a concern with all the gunfire going on in the arena. But Tench is comfortable having her young 4-H members there; the mounted shooters are look out for everyone like a family, she said.

"It's such a great, safe environment," she said.

A variety of horses are used in mounted shooting. They can be quarter horses, ponies, paso finos, anything.

"If you can get the acclimated to the gunfire, you can ride them," Derry said.

Unlike other equestrian sports such as hunting and jumping, there's no one scoring a rider's form.

"There's no judges," Derry said, "you can pull a horse out of your pasture and do this."

After seeing the mounted shooters on Sunday, Brandon thinks he'll try to get into the sport.

"The horses, they're really impressive because they're so fast," he said. "(It's) great to ride your horse and have a little bit of fun."