Now, almost a decade later, he continues to split his time between the satellite circuits and the Web.com Tour in the hope of eventually making his way onto the PGA Tour proper.
“I love it out here,” he says. “I feel really settled in Phoenix and I’m really enjoying my golf. The weather is the biggest difference. I can practice all year round.
I can go out to hit some balls at 5.30am and it’s already 95˚F
“You know, at the height of the summer, I can go out to hit some balls at 5.30am and it’s already 95˚F, which is, what, mid-thirties in Celsius?
“You just don’t get that opportunity in Scotland. A lot of the time, it’s too cold to do any proper practice. But in the States, it’s a bit like playing golf in a dome. Even in the winter, it’s about 75˚F (23˚C), so it’s perfect.”
The standard of the competition Gunn is coming up against would be easy for the average golf fan to underestimate. Easy, but stupid.
“It’s really competitive,” he adds. “Two years ago, when I played on the Web.com for the first time, you had guys like Tony Finau, Justin Thomas, Smylie Kaufman and that’s just to name a few.
“There are obviously loads more, and that’s to say nothing of the guys who have maybe been on the PGA Tour for a number of years but have come down onto the Web.com, so you’re playing against top, top players pretty much every week.”
Of course, the style of golf Gunn grew up playing in the Scottish Highlands is just about as far removed from modern American golf as it is possible to be.
He traded links golf, in often-windy conditions, for target golf, in near flat-calm glorious sunshine. That, in turn, required a change of approach.
I pretty much had to change my entire game
“The two styles are chalk and cheese,” he smiles. “When I played in Scotland, I used to hit a big draw with every club but I pretty much changed my entire game to start hitting cuts when I went over there.
“It’s just target golf in the States. You know, if the ball lands on the green, it’s going to stop on the green. Half the time, you’re worried about it spinning off the green.”
It’s slightly ironic, then, that his best result as a professional – and certainly his biggest pay-day – came on a links-style course… in America!
Gunn qualified for the 2015 US Open played at Chambers Bay. He was one of 20 players from the UK to take part in the self-styled ‘toughest test in golf’ that year; of those, only Rory McIlroy posted a better finish.