'You know, there's lot of birdies out there,' said Inkster, who bested Jen Hanna's record from last year by one shot. 'I got a little sloppy on the par-5s, so I think that's something I need to get better on tomorrow. But I'm happy. No bogeys, and I gave myself a lot of opportunities for birdies.'
Inkster owns a three-shot lead over Nancy Scranton and Dorothy Delasin, while Laura Diaz and Pat Hurst are a shot back at 10-under-par.
Two-time defending champion Annika Sorenstam rebounded from an opening-round 72 with a 66 on Friday. She is tied for 20th at minus-six.
Inkster collected three birdies on her front side and added another at 10. It was deep in her second nine that Inkster soared to the top of the leaderboard.
She drained a 12-foot birdie putt at the par-5 13th and made it two in a row with a 30-footer at No. 14.
Inkster, who won this title in 1999, wedged her approach to 10 feet to set up birdie at No. 17, and she capped her round with a two-foot birdie putt at Randolph North Golf Course's closing hole.
The Hall of Famer acknowledged that owning the lead midway through the tournament is nice, but she must continue her birdie assault if she wants to walk off with career win No. 27.
'Even though I've played really well for the last two days, I've got to keep playing well or I'm going to get lapped,' said Inkster. 'It's not like if I stay where I'm at, I'm going to win. I've got to keep playing aggressive.
'You see people shooting six or five-under a lot out there, so I've got to keep doing what I'm doing. There are a lot of girls behind me that could catch fire like I did today.'
Scranton had the lead in round two but she ran into trouble in the middle of her back nine, the front side at Randolph North. At the fourth, Scranton two-putted from four feet for bogey, and followed it up two holes later with another bogey when she failed to get up and down out of a bunker and fell to 9-under-par.
She fought back with birdies at Nos. 8 and 9 to get within three of Inkster.
'I feel good; we've been lucky and have done a good job with club selection this week,' said Scranton,. 'Sometimes you get lucky, then sometimes you talk yourself into thinking that it's not a good yardage even if it is.'
Delasin holed a six-foot birdie putt on her last hole to join Scranton in a tie for second.
Akiko Fukushima (65), Laura Davies (66), Maria Hjorth (67), Marisa Baena (67), Michelle McGann (68), Rosie Jones (68), Mhairi McKay (70) and Karen Weiss (70) are tied for sixth at 8-under-par 136.
Karrie Webb is part of a group at 7-under par.
Ashli Bunch shot 4-over 76, 12 shots higher than the 64 that gave her the lead in the first round. She slipped into a tie for 32nd place at minus-four.
The 36-hole cut fell at 2-under-par 142 with 75 players making it to the weekend.
Full-field scores from the Welch's/Circle K Championship