Gage stands at 16-under-par 200 alongside overnight co-leaders Sonny Skinner and Bo Van Pelt, who each shot third-round 68s.
Craig Bowden stands alone in fourth place at 15-under-par 201. First-round leader Tom Carter and Bubba Dickerson are one shot back at 14-under-par 202.
Van Pelt grabbed the early lead at The Dominion Club as he rolled in birdies on each of the first two holes. Skinner also birdied the second to trail by one after two holes.
Skinner found himself in the lead shortly there after. Van Pelt bogeyed the fourth before Skinner birdied No. 5 to take a one shot lead. Van Pelt came right back to birdie the sixth and grab a share of the lead.
Gage, playing four groups ahead of the leaders, notched just two birdies on the front side. He birdied the 11th to start a strong back side. He burst up the leaderboard by rolling off four straight birdies from the 13th to climb to minus-15.
'You can't be impatient if you don't get it under-par early because there are plenty of opportunities,' said Gage, who has made just three cuts all season. 'Guys can just out there and find the 63s and 64s that are out there. I was pretty proud of myself for just staying patient today.'
Meanwhile, Skinner had gotten to 15-under with a birdie at the 10th but dropped a stroke at No. 13. He moved back to 15-under with a birdie at the 15th. After a string of eight straight pars, Van Pelt also birdied the 15th to get to minus-15.
Gage grabbed the clubhouse lead at 16-under when he birdied the 18th.
'It's been quite some time since I've played really well,' Gage said. 'I'm trying to get my game back in order where I can compete. That's why we play -- to get that feeling in your gut, to get on edge.'
Skinner and Van Pelt both parred Nos. 16 and 17 before birdieing the final hole to join Gage in the lead at minus-16.
'There are a lot of guys playing well right now and you can't stay in neutral,' Van Pelt said. 'If you're not going forward the whole time, you're going to get passed.'
'I feel real comfortable here. I like Richmond. I've had some good things happen to me here and I think there's some good things left,' said Skinner, who has made just 10 of his last 38 cuts. 'You've got to have four good days to have a chance to win a golf tournament and I'd like to think that right now I've got three, so I'm pretty pleased.'
Zach Johnson, Wes Short and Roger Tambellini share seventh place at 13-under- par 203. David Branshaw leads a group that includes Mike Brisky, Daniel Chopra, Erik Compton, Ken Duke and Lucas Glover one stroke further back at minus-12.