"It makes me want to vomit," he bluntly says of a moment that marked his short NFL preseason stint in 2004. "To think I was just kicking a ball without any technical knowledge at all."
Things have come a long way since then.
Largely thanks to Chapman's Pro Kick Australia school, founded on the lessons he learned as an NFL hopeful, the country is cranking out punters to major US college programs and infiltrating the pros.
No fewer than 65 Pro Kick graduates will suit up for Division I schools this year, according to Chapman, and three are likely to stick on NFL rosters.
They include Seattle Seahawks rookie Michael Dickson, who skipped his senior season at Texas after winning the Ray Guy Award, given to college football's top punter.
Like most other Pro Kick students -- and like Chapman himself -- Dickson played Australian rules football and had little understanding of the sport the Aussies call "gridiron."
No matter. After a brief tryout -- which he attended on a whim with friend Oscar Bradburn, now with Virginia Tech -- Dickson enrolled in Pro Kick in March 2015.
By September, he was booming punt after punt for the Texas Longhorns in front of more than 80,000 at Notre Dame.
"I never really watched a full game of American football until I played my first game against Notre Dame," Dickson recently admitted to the Seattle Times.
"It took me two years to really fully understand (the rules)."
Dickson's talents shone in a win at the Texas Bowl in December, when he landed 10 punts inside Missouri's 20-yard line and walked away as the game's MVP.
Texas coach Tom Herman said he had never seen a punter affect a game that way.
"That's what we try to do," says Chapman. "We feel like our duty is to bring attention back to the punting game so that coaches realize, hey, if we've got a good one, we can attack more,"
Dickson will likely be joined in the NFL this season by fellow Pro Kick alumnus Jordan Berry of the Pittsburgh Steelers and Cameron Jo