Americans to fore in Senior Open
Calcavecchia - one of three overnight leaders - made six birdies in his three-under 69 before being joined on seven-under by Rinker and Canada's Rod Spittle, whose afternoon 67s were the joint second-lowest rounds of the week at Walton Heath.
In-form Australian Peter Fowler is two shots back after a 68, with American pair John Cook (67) and Mike Goodes (70) together on four-under.
With players from the United States filling six of the top nine places - as well as 20 of the leading 31 - and three-time winner Tom Watson also getting back in contention with a bogey-free 68 for one-under, the likelihood of an eighth American winner in nine years was growing.
Langer isn't expected to be challenging tomorrow, though, after a four-over 76 left him nine shots off the pace.
Calcavecchia and Rinker live near each other in Jupiter, South Florida and are also childhood friends, playing junior golf from the age of 12. Their careers have taken different paths since then, however. While the 50-year-old Rinker is unknown outside the US and without a career victory to his name, Calcavecchia is best known for winning the British Open at Troon in 1989 and has 12 more victories on the PGA tour.
Calcavecchia is bidding to become the fourth player - after Watson, Gary Player and Bob Charles - to achieve the British Open double and has a great chance if he maintains his form off the tee this week. "That would be awesome company to keep. They're three Hall of Famers. That would be really special," said Calcavecchia.
Rinker, in his first season on the Champions Tour, only sealed his spot at Walton Heath with a top-10 finish at the Dick's Sporting Goods Open at Endicott, New York last month.
Fowler, a two-time winner on the Senior European Tour this season, is handily place on five-under after a 68 - aided by the holing of a pitch for birdie on No 16 - while Cook followed Rinker and Spittle in shooting a flawless round of five-under. That score was only beaten by England's Kevin Spurgeon, whose 66 contained eight birdies.
Australia's Mike Harwood and Zimbabwean-born Mark McNulty shared the overnight lead with Calcavecchia but carded 74 and 76 respectively to drop back. Langer also had a poor round, a double-bogey on the par-4 No 4 adding to three other dropped shots.