Cameron Yancey, Anthony Painter, Mike Grob, Han Lee and John Morgan share third place at 5-under-par 67.
Play will be contested at both the Stadium Course and the Nicklaus Course throughout all six rounds of the tournament. There is no cut and the low 35 players and ties will receive their PGA Tour cards for 2003.
Barber opened on the back nine at the Nicklaus Course and collected six birdies over his first eight holes. That streak immediately put him at the top of the leaderboard but birdies at the par-5s on the front side, 4 and 7, sent him to 8-under and gave the outright lead.
Barber, who posted seven top-10 finishes on the Canadian Tour in 2002 and won that tour's money race in 2001, ran into trouble at the par-3 eighth. He knocked his tee ball into the water and double-bogeyed the hole to fall back into a tie for first place.
'On the back nine, I just started to make some loose swings, but I got away with it,' said Barber. 'You know with six rounds, no matter what kind of start you get off to, you still have to stay in the present. It worked today and I'm sure the nerves will be there the next few days.'
Gangluff, a PGA Tour rookie in 2002, also began his round on the second nine and played a more consistent round than Barber. He collected three birdies on each nine holes to match Barber in first at minus-6.
'I played well. I really did,' said Gangluff, whose best finish this season on tour was a tie for 19th at the FedEx St. Jude Classic. 'I played solid and just carried it over from the second stage. I played well there.'
Bob May, who lost an epic playoff battle to Tiger Woods at the 2000 PGA Championship, is part of a logjam in eighth place at minus-4.
Steve Pate, a two-time Ryder Cupper, and Andy Miller, son of television analyst Johnny Miller, are in a group tied for 36th at 2-under-par 70.
Full-field scores from the PGA Tour Qualifying Tournament