First-round leader Deane Pappas managed an even-par 71. He was joined in a tie for second place at 9-under-par 133 by Erik Compton (65), Jason Schultz (67), Jeremy Anderson (65), Charley Hoffman (68) and Tom Scherrer (69).
Durkin opened with a birdie at the first on the North Course at Crestview Country Club. After four pars in a row, he stumbled to a bogey on the sixth.
The 31-year-old got that stroke back with a birdie on the par-4 seventh. Durkin made it two straight as he birdied the par-3 eighth before he moved to minus-9 with a birdie on the par-4 ninth.
Durkin parred the first four holes of the back nine. He got to 10 under with a birdie on the par-5 14th. After a par on 15, Durkin birdied the par-4 16th and parred his final two holes to finish at minus-11.
'I hit it pretty good today,' Durkin said. 'I'm finally making more putts too. I started working so hard on putting that it got maddening. I finally said the heck with it. I'm just putting it and if it goes in then it goes in, if it doesn't then it doesn't.'
Pappas played the back nine first on Friday. He birdied the 14th and 18th to make the turn at 11 under and went to 12 under with a birdie at the second. Pappas then bogeyed the par-4 sixth and double bogeyed the next to drop back to minus-9.
'I was playing pretty good until No. 6, my fifteenth hole,' said Pappas. 'I just couldn't see the lines today. Just about every putt looked like it could go both ways.'
Anderson also played the back side first in the second round. He birdied the 10th, his first.
The 27-year-old jumped to 6 under with an eagle on the par-5 18th. Anderson moved to minus-8 with birdies on the second and fourth. He joined the crowd at 9 under with a birdie on the ninth.
'It was very solid today. I didn't really put myself in any trouble', said Anderson. 'I was able to find my rhythm Thursday afternoon on the range and carry it to the course today.'
Compton birdied the second fourth to move to minus-5. He came back with a birdie on No. 7. The 25-year-old parred his next six holes before dropping in a birdie putt on the 14th.
The former University of Georgia Bulldog closed with birdies on 16 and 18 to move into a share of second place.
The cut line fell at 3-under-par 139 with 65 players moving on to the final two rounds. Among those missing out on the weekend were Dicky Pride (minus-2), Bill Haas (minus-2) and former Battlefield promotion winner Tom Carter (minus-1).