RENO, Nev. » Joe Sellers knew Chris Ault way back in the 1960s, when a pistol was just a gun, not a trendy football offense.

“He was a good teammate,” said Sellers as the full moon rose, the mercury dipped and players headed to the buses after the University of Hawaii football practice Thursday at Reno High. “He was a good leader on the field, a good sprint-out quarterback.”

Sellers, who played guard at Nevada, was at the Warriors practice to visit his old friend and Willamette linebacker nemesis, UH defensive ends coach Cal Lee. Sellers is a legendary coach in these parts, retired from Wooster High in Reno.

A few years ago Ault was retired from coaching, too, after building a Hall of Fame career at Nevada, where he’d seemingly transitioned happily into the athletic director’s post. Who would have guessed he’d return to the Wolf Pack sideline and change the way many teams play — at the high school, college and pro levels, by inventing a new offense?

Six years after its unlikely birth in an old gym on the Nevada campus (as Ault and then-running backs coach Jim Mastro used a helmet for a ball and tape for player positions), the pistol is still going strong and continues to proliferate. Just last week, Florida joined the ranks as offensive coordinator Charlie Weis needed a way to get the Gators going. It worked, as Florida beat Vanderbilt.

More than 40 colleges — including WAC-rival Hawaii, which plays here on Saturday — several NFL and untold number of high school teams have installed the pistol to at least some degree. There are many variations, the main formation constants being the quarterback lined up 4 yards behind center, and a lone running back right behind him.

“It’s pretty neat,” said Ault, who hosts several coaches each spring, sharing pistol basics. “I like to look and see what other teams are doing with it. It’s like any other offense. It’s got its weaknesses and strengths. We’ve learned from some of these other guys as well.”

Ault says he invented the pistol because he wanted to get quarterback Jeff Rowe “more involved in all the phases” of the offense. Another goal was to get the ball to running back

B.J. Mitchell faster.

“One day in January, he says, ‘Let’s go downstairs,’” Mastro recalled. “He says, ‘I’m the quarterback, you’re the running back. Let’s try this.’ We used a helmet for the ball and duct tape for positions. I thought it was crazy.”

Ault saw something in the new geometry he thought would work, and decided that every snap of spring practice would be done in the pistol. The logic is based in timing: If the center-quarterback exchange is completed faster, that means the entire offense can get off to a faster start.

Changing the distance of the center shotgun snap was what caused the most difficulties at first.

“It was Keystone Cops. The snaps were all over the place,” said Mastro, now the offensive run-game coach at UCLA, where the pistol is also run. “I told the other coaches it was time for us to update our resumes, we were all going to get fired. But 10 practices in, it looked like we might have something.”

It clicked, and Nevada is 56-30 since its installation. In 2009, the Wolf Pack led the nation in rushing and became the first team in college football history with three 1,000-yard rushers.

The rest is history, or mystery to most defenses trying to stop it. UH’s defense has muscle memory from last year’s 27-21 win, and UH defensive coordinator Dave Aranda has extensive video of the pistol. His collection goes back to 2005, when he and UH running backs coach Brian Smith were on the staff at Division III Cal Lutheran, and UH coaches shared what they had on Nevada’s offense.

But, like any great chef, Ault doesn’t give away all the secret ingredients.

“He never puts anything on paper. He shares, but he tells you what he wants you to know,” Mastro said. “Coach Ault never sleeps and is always reinventing himself. Some other coaches hate him, but that’s because he beats them.”

Reach Dave Reardon at dreardon@staradvertiser.com or 529-4783