Late February, and the parking lot is jammed with cars and RVs, some from as far away as Saskatchewan.

It's time for the annual Satellite Spring Grand American at the Tucson Trap & Skeet Club.

Before the weeklong event is over, more than 1,000 participants from all over the United States, Canada and Mexico will have aimed their shotguns at clay targets flying through the air. Repeatedly.

"We threw 903,000 targets during the event," club Treasurer Michael Braegelmann says. "It's our biggest event." But far from the only one.

Besides hosting other events throughout the year, the club has been designated by USA Shooting - the national governing body for Olympic shooting sports - as a regional Olympic training center and will host the World Cup in 2012.

"Every country that will be in the Olympics will be here in Tucson," says club President Lee Bachman.

Billed as one of the largest facilities in the country, the club, located on 80 acres at 7800 W. Old Ajo Highway, boasts 14 skeet fields, 25 trap fields, two five-stand sporting clay fields, a 5,000-square-foot clubhouse with a restaurant and 200 RV hookups.

Yet most Tucsonans, including yours truly - at least until recently - are unaware of its existence.

"We're the best-kept secret in Tucson," says Tom Moore, a member since 1961. The club began in 1948 on 40 donated acres at the southwest corner of East 22nd Street and South Pantano Road.

According to a history written by Moore, the only other facility in town back then was a soon-to-be-demolished two-trap layout at Randolph Park, next to the golf course.

Tucson Trap and Skeet's first clubhouse came from two barracks hauled to the site from Davis-Monthan Air Force Base and joined together. The shooting line had nine trap fields and two skeet fields.

Members paid $50 for a lifetime membership. Affiliated with the Amateur Trapshooting Association, the club lured so many to its "big shoots" that it was soon negotiating with a nearby sand and gravel plant to build four trap fields there. The fields were used only during big events.

In time, however, encroaching housing made the club's location untenable.

In 1973, Glenn Harrison, treasurer of the club, made a successful bid of just over $40,000 to the Bureau of Land Management for 80 acres on Old Ajo Highway.

Jim Pfersdorf, who also joined the club in the early '60s, remembers his first glance at the new property.

"I was pulling weeds at the club, and Glenn Harrison said, 'Let's go for a ride,' " remembers Pfersdorf. "I thought we were going to Ajo. He said, 'This is the site of the new gun club.' "

By early 1976, the club had become a reality. And nope, plunking it down on the opposite end of town didn't dint membership one bit, says Pfersdorf.

More than 900 now belong to the club, about evenly divided between life and annual memberships. Life memberships now cost $400; annuals goes for $75.

Nonmembers pay $7 a round for 25 targets. The club also rents out guns and ear and eye protection for those who "just want to come out and see what it's about," says Braegelmann.

Five days into the club's biggest annual event, the ground is littered with empty shotgun shells - but only temporarily. "The club picks them up at the end of the day and offers them to our members for reloading," says Braegelmann.

Meanwhile, the pulverized clay targets are ground up and mixed with the soil to control the dust, says Braegelmann. "And we drag the fields and mine the lead pellets every three years, for recycling."

The club also offers a gun-safety and shooting program for kids ages 9 through 18, with about 70 participants. All are taught by trained, certified and licensed volunteers.

Taz Gloria, 15, a freshman at Mountain View High School, is in his sixth year of shooting here at the club and is a winner of numerous sub-junior state events. "My grandfather got me out here," says Gloria, shouting to be heard over the blasts of 12-gauge shotguns.

Says Bachman, the club president: "This is how you come up the ranks."