Former Ryder Cup star Oliver Wilson, 2011 Silver Medal winner Tom Lewis, and Richard McEvoy are joined by Chilean Mark Tullo and Frenchman Alexandre Kaleka.
All five began the event at St Andrews with eight-under 64s, while five other Brits are a shot behind on 65 - Tommy Fleetwood, George Murray, Mark Forster, Matthew Baldwin and Jamie Donaldson.
Wilson, a five-times runner-up on the European Tour who played in the 2008 Ryder Cup at Valhalla, said: "I'm playing a lot better.
"For the first time in probably over a year actually, I have some control over my shots and able to hit the shots and trust it under pressure, as well.
"I'm driving the ball way, way better, which is essentially the thing that disappeared."
Lewis, who captured the Silver Medal at Royal St George's in 2011 and then won the Portugal Masters on his third start as a pro, said: "I played well today. My putting was a lot better.
"The last couple of weeks, I've been struggling, even though I've shot some good scores, but today was perfect. If I can do some of that again for the next couple of days, then I'll be right up there for Sunday.
"Obviously I'm solid on the first 18; Friday is sort of my enemy. If I can try to get away from that this week, I'll be fine."